Shogi Variants | Dr Eric Silverman

Nov 20 2021

11×11 Shogi, Part I: Shinjuu Shogi

If you’ve read this blog in recent years, you’ll be well aware that I consider Shogi one of the finest games ever created, surpassed only by its larger cousin Chu Shogi, which I believe to be the greatest traditional Chess-like game on the planet. As I’ve been working with Stephen Tavener and his Ai Ai software to slowly and laboriously bring Shogi and its modern variants to life as well as the fascinating historical variants, I’ve been inspired to build on what I’ve learned about the historical Shogi variants and create a modern variant that brings the unique flavour of the ancient large Shogi games into the 21st century.

In this article I’ll talk a bit about the process of creating this variant, my design goals for the game, and my own evaluation of what makes a Shogi game feel like a Shogi game. As this variant has evolved through constant, endless playtesting and experimentation, I feel I’ve learned a lot about what makes the Shogi family work so well, so I decided to share this here to generate discussion and hopefully help others who may be experimenting with Shogi variants of their own.

The Birth of Shinjuu Shogi

While testing the various historical Shogi variants in Ai Ai, I spent quite a bit of time with Wa Shogi. Wa Shogi is an 11×11 game with 27 pieces in each player’s army, and like Tori Shogi it uses a completely different set of pieces from the normal Shogi assortment, including different Pawns and Kings (though with the same moves). Wa Shogi is an excellent game in its modern form, in which it’s played with drops, but I felt the game lacks a certain intensity compared to the other historical variants, because the pieces are generally weak:

While there are a few pieces with ranged moves in Wa Shogi, the majority of the pieces have short-range stepping moves only. That means the game works very well with drops as in modern Shogi, but it also gives the game a slower, less intense tactical experience than the other historical variants, which are generally pretty packed with powerful pieces. I sometimes felt that tactical fights in Wa Shogi were too localised, and the more powerful pieces could mostly just avoid the masses of much weaker stepping pieces. In perusing the few recorded games of Wa Shogi between strong players, I was also surprised to find that most of them were shorter than a typical game of 9×9 modern Shogi (the average tournament Shogi game lasts about 120 moves).

That inspired me to try to make my own take on an 11×11 modern Shogi variant, but this time incorporating a range of pieces from the large historical variants. My goal was to generally increase the power level of the pieces, allowing for sharp tactical play, but to balance the piece array so that the games would also be a bit longer than Wa Shogi. Ideally, the game would serve a dual purpose as both a fun game in its own right, and an enticing preview of the creative and unusual piece types present in the old Shogi variants; with luck, perhaps players of this new variant might be inspired to take a look at the games that originally housed these interesting pieces.

I felt the best way to achieve the second goal would be to capture some of the interesting cultural elements that exist in the old Shogi variants, so I decided to centre the game’s armies on four mythological creatures we find on the board in Tai Shogi: the Blue Dragon, White Tiger, Vermillion Sparrow and Turtle-Snake. In Japan these beings are called Divine Beasts, or Shinjuu, and hence Shinjuu Shogi was born.

Design Goals

The dual design goals of developing an enjoyable modern Shogi variant and an inspiring selection of ancient Shogi pieces meant that I’d need to break down the essential properties that make for a good Shogi game, and the aspects of the historical variants that could feasibly be transferred into a modern Shogi framework. In my view the key aspects that make Shogi so compelling are these:

Asymmetric pieces biased toward forward movement — If we take a look at the piece types present in the starting array of modern Shogi, we can see that only the Bishop and Rook have symmetric moves. The Pawn, Lance, Silver General, Gold General, and Knight are all asymmetric, and most or all of their movements are pointed directly forward. This aspect contributes to the generally aggressive feel of the game, because retreat is often not really an option.
Slow opening and aggressive endgame — Part of the appeal of Shogi stems from the distinctive way in which play evolves over the course of the game. In Chess, the opening is very sharp, because the board is small and packed with long-range pieces that can start causing trouble instantly. In contrast, endings tend to be intricate, strategic affairs requiring intense calculation due to the lack of mating material left on the board. In Shogi, however, openings tend to be slower and more flexible; players aim for advantageous middlegame positions, but due to the size of the board and the slower pieces, following precise move orders is less critical than in Chess. Meanwhile, Shogi endings are savage and explosive — both players have most or all of their pieces still on the board, thanks to the drop rule, so the end of a Shogi game is typically a tense race to checkmate as both players mount vicious attacks with drops and promoted pieces.
Minor and major piece promotion — In Shogi every piece except the King and Gold General is able to promote upon reaching the enemy camp, unlike in Chess where only the Pawns promote. Promotions happen frequently, given that reaching any of the opponent’s three ranks allows a promotion, and pieces can be placed in the promotion zone when dropped. The ability of nearly every piece to power itself up again increases the intensity of Shogi tactics, and also complicates the concept of material value in the game as compared to Chess. Promoted pieces hold extra value because if your opponent captures them they get a weaker piece instead. We see this reflected in Shogi proverbs like ‘a central Tokin [promoted Pawn] cannot lose’. In other words, the Tokin is a great way to hold the centre of the board, since it controls a number of squares, but when taken it only gives your opponent a Pawn.
Promotion can be deferred — Sometimes, a Shogi player will defer promotion of a piece, because not all promotions are directly upwards-compatible with the original piece; in other words, the promoted piece may not include the moves of its ancestor in its arsenal. For example, a promotable Knight may be left as-is even if its eligible for promotion, because the owner needs the Knight’s aerial threat, which goes away if the Knight promotes to Gold General. In fact, deferring Knight promotion is so commonplace that there’s another Shogi proverb about that, which simply states ‘Don’t promote the Knight!’

So, in order to make a fun modern Shogi variant that would capture and retain the interest of Shogi players, I felt I would need to capture all of these elements in some fashion in Shinjuu Shogi. However, the ancient Shogi variants (other than Wa Shogi) are all played without drops, and simply adopting the drop rule transforms those games into endless slogs; the many powerful pieces keep returning to the board and building powerful defensive castles around their King, making checkmate exceedingly hard to achieve. That meant I’d need to think about the fundamental aspects of large Shogi that give these ancient games their distinctive character, and try to work out which of those could be transferred intact to the modern Shogi battlefield:

Lots of powerful pieces — As we can see in the summary of the Chu Shogi army above, the initial position of the game is filled with powerful attackers. The Rook and Bishop of 9×9 Shogi are present, but this time in pairs, along with pairs of their promoted forms, and multiple other pieces that are substantially more powerful still. The same dynamic persists in the other large variants, with each larger game bringing in even more powerful pieces. These power pieces help maintain tactical excitement in these games even when playing on these gigantic battlefields.
Thematic richness — Many of the larger Shogi variants incorporate pieces linked to classical Japanese and Chinese mythology. Alongside the Divine Beasts, we find pieces like the White Elephant (bringing to mind the white elephant the Buddha’s mother saw in a dream before his birth), the Lion Dog (the creature that defends many temples throughout Japan), the Teaching King (thought to symbolise the Lotus Sutra) and many more. This thematic element and the tendency to link powerful pieces to mythological or religious figures immerses the players even more in the battle unfolding on the board.
Even more asymmetry — While modern Shogi does have an asymmetric starting position, due to the Rook and Bishop only being present as singletons rather than pairs like the other pieces, the large variants take this much further. Wa Shogi is the most extreme example, where only the Sparrow Pawns are present in multiples in the starting position; Dai Dai Shogi is similar, with most of the starting position’s 64 piece types existing as singletons, leading to a heavily asymmetric setup. This asymmetry not only adds tactical variety and intricacy, it also lends a certain additional Japanese-ness to the game; asymmetry is highly valued in traditional Japanese arts.
Different approaches to promotion — In modern Shogi all pieces promote to Gold General, except for the Rook and Bishop. In the ancient variants, we see much more varied takes on promotion. For example, we tend to see weaker pieces gain very significantly in strength when promoted, as a reward for marching them all the way across these huge boards. In a few cases we have pieces that actually demote, pushing players to maximise the utility of the piece’s original form. We also see pieces that are very direct enhancements of the original piece, like in Maka Dai Dai Shogi where single-step pieces promote to ‘free’ versions of themselves that may slide unlimited squares in the same directions their original form could step. Maka Dai Dai also has the unusual Buddhist Spirit and Teaching King, which if captured transform the capturing piece into a copy of themselves, ensuring that they hardly ever leave the board permanently!

In order to bring the ancient Shogi feel to the modern Shogi battlefield, I’d need to somehow combine these different properties of these two sub-genres of the Shogi family. However, I was unsure whether some of these properties could be reconciled at all: could I increase the power levels of all the pieces without unbalancing the game or trivialising Shogi’s rich tactics? Would it be feasible to adopt different approaches to promotion in a drops-based game, or would Shogi’s explosive endgames be too quickly curtailed by the opportunity to generate strong promotions shortly after a drop?

The only way to judge these points would be through experimentation. So I began constructing possible initial positions for the game, with the four Shinjuu pieces taking up flank positions and the centre providing a home for strong pieces that could both mount damaging attacks and defend the King when called upon to do so. Then I embarked on a long, meticulous testing process, investigating dozens of possible starting arrangements and playtesting over and over again, discarding piece selections and positions that failed to produce appropriately modern-Shogi-like gameplay.

Thankfully I’m going to spare you all the details of that process, and instead show you the result! What you’ll see below is the 62nd version of Shinjuu Shogi (!), but I’m finally at a point where I’m ready to release it soon.

Meet Shinjuu Shogi

Shinjuu Shogi starting position with traditional kanji pieces.

Let’s be clear on this from the start — Shinjuu Shogi is a big game. The board is an 11×11 grid with 121 squares, substantially bigger than modern Shogi’s 81-square board. Players start with 27 pieces in their armies, nearly all of which can promote, giving us 28 different moves to remember — the same number as in 12×12 Chu Shogi. Wa Shogi is also an 11×11 game and has 25 moves to remember; the additional moves exist here thanks to the presence of the Dogs in addition to the normal Pawns, and the two additional pieces in the starting array.

The selection of piece types references most of the historical variants:

The Pawn, Gold General and the King are present across all variants (except Tori and Wa).
The Phoenix, Kirin, Ferocious Leopard are everywhere in the large variants, but for me they mostly bring to mind Chu Shogi.
The Divine Beasts — Blue Dragon, White Tiger, Vermillion Sparrow and Turtle-Snake — come to us from Tai Shogi, but here we use the Taikyoku Shogi moves for the Blue Dragon and White Tiger, and the Tai Shogi moves for the Vermillion Sparrow and Turtle-Snake. The White Tiger and Blue Dragon promotions also come from Taikyoku Shogi.
The White Elephant and Fragrant Elephant come from Dai Dai Shogi, and their moves are vertically mirrored versions of each other.
The Dog comes to us from Tenjiku Shogi, as well as its promotion to Multi General.
The Fierce Eagle and Old Kite join us from Tai Shogi, with their moves drawn from the Japanese sources rather than the move promoted in The Shogi Association rules.
The Mountain Witch and Wizard Stork join us from Dai Dai/Maka Dai Dai, as the promotions for the Vermillion Sparrow and Turtle-Snake, respectively.
Various pieces and promotions come from Taikyoku Shogi: Great Standard; Walking Heron (promoted Fierce Eagle); Bird of Paradise (promoted Old Kite); Wooden Dove (promoted Phoenix); Free Boar (promoted Gold General); and Copper Elephant (promoted Ferocious Leopard).
The Golden Bird, the strongest promotion in the game, originates in Dai Dai/Maka Dai Dai but uses the Taikyoku move, which gives it the ability to leap over up to three pieces while sliding along the forward diagonals.

Shinjuu Shogi therefore contains references to most of the large Shogi variants, with the notable exception of Ko Shogi. Ko Shogi is a fascinating game with incredibly creative and complex piece movements, but the most interesting pieces in that game are simply too powerful to have a place in a game the size of Shinjuu. Similarly, the infamous Fire Demons and jumping Generals of Tenjiku Shogi can’t appear here either, as they would dominate the board completely.

I’ve built this game to try to capture the quirky character of the large Shogi variants:

Asymmetry — The starting position is asymmetrical, with the Blue Dragon, Turtle Snake, and Old Kite starting on the left side, and the White Tiger, Vermillion Sparrow and Fierce Eagle on the right. The pieces themselves also have asymmetries in their movements, including both the step-moving pieces like the Old Kite and Fierce Eagle and the various sliding pieces like the Divine Beasts and the Elephants.
Promotions — The Pawns promote to Tokin (Gold General), which is a nearly universal truth across the whole Shogi family. The other promotions here are specifically inspired by the large Shogi variants. The short-range pieces tend to gain significant power on promotion, graduating from single-step movers to long-range attackers. The Dog becomes a sliding piece that slides in the same directions it could step. The four Divine Beasts are straight upgrades of the unpromoted pieces, gaining additional sliding directions and retaining their previous moves as well.
Promotion quirks — The Fragrant Elephant and White Elephant are vertically mirrored versions of each other, and their promotions are both strong but have a trade-off: in each case, the promoted form gains substantial power but loses their original two sliding moves, meaning that in some cases you may want to defer promotion. Similarly, the Kirin and Phoenix gain enormous mobility on promotion, but their jumping moves change. The Old Kite and Fierce Eagle gain vertical slides and some new options, but the Old Kite loses horizontal movement while the Fierce Eagle loses the rear diagonals. All these quirks mean that promotions sometimes must be deferred to make use of the unpromoted piece’s subtle differences.
Powerful pieces — The amount of attacking power on the board is massively higher than in Wa Shogi. The starting array includes multiple-square step-movers, several different sliding pieces, and two leapers. The promoted pieces add some powerful threats: the Wooden Dove is able to leap and then slide afterward, providing dangerous long-distance attacking potential; the Golden Bird is able to leap over up to three pieces in certain directions, enabling deadly cross-board strikes; and the Great Dragon has a sideways 2- or 3-square leap that is lethal in certain close-quarters situations.
Pacing — Piece placement has been optimised to generate a pace of play that follows the modern Shogi model. The opening position offers 39 possible first moves, which will hopefully reduce the likelihood of very deep opening analysis developing. All Pawns are protected at the start of the game, preventing any super-early tactical shots, and the longer-range pieces are tucked behind the Pawns and thus require additional moves to be developed. The result is a relatively deliberate and strategic opening phase leading up to a very active middlegame. The middlegame itself is more intricate than Wa Shogi, given the higher piece density and greater piece mobility, which allow for complex and varied tactics to emerge. The endgame is characterised by dynamic and aggressive play, with frequent drops supported by powerful long-range attacks from promoted pieces.
Thematic appeal — The Divine Beasts are the thematic core of the game, and the other pieces have been chosen to amplify the feel of an epic battle between mythological forces. The Dogs, Old Kites and Fierce Eagles are the vanguards, leading these armies of beasts and gods into battle. The King is protected by a Great Standard, which effectively guards the second rank and has strong forward attacking potential when given the opportunity. The Phoenix and Kirin (Unicorn) provide nimble leaping attacks that can complicate enemy attempts to secure their King. The Fragrant and White Elephants are stalwart defenders that blossom into vicious airborne attackers when given an opening; their promotions are thematic, with the White Elephant of Buddhist mythology transforming into a Golden Bird symbolising enlightenment, while the Fragrant Elephant matures into a Great Elephant, losing some forward attacking power in exchange for strong rearward sliding capabilities.

The result of all this is, I hope, a game that combines the dynamism of modern Shogi with the creative character of the ancient large Shogi variants. To give it a distinct personality I included pieces with unusual moves and abilities:

The Wooden Dove may jump 3 squares diagonally, then optionally slide an additional 1-2 squares outward.

These kinds of unique moves are characteristic of these old games. Perhaps the most iconic piece of the large Shogi variants is the powerful Lion that can move and capture twice in a turn, but the Lion and its many cousins are simply too strong to live happily in a drops-based game. So instead I selected pieces with unusual sliding modes from Tai and Taikyoku Shogi, which are still strong and unique but not overpowering. These pieces also add further dynamism to the game by providing moves that neatly ignore dense defensive formations, forcing players to adopt flexible defences. I found that having a few leapers in this game also helped counterbalance the much higher attack density, and prevented games from dragging on for too long due to an overabundance of defensive power.

I should note that I made a possibly controversial decision with this game to have nearly all pieces promote to a piece type that is not present in the initial position. Pawns promote to Tokin, which moves identically to the Gold General, but otherwise all pieces upgrade to something new. This was a conscious choice, which I made to ensure that Shinjuu would maximise the opportunity to showcase a wide variety of different pieces from the ancient variants. This does mean players need to familiarise themselves with more moves, but I tried to choose promotions that have some vaguely logical connection to their unpromoted forms, particularly for the shinjuu themselves. As you’ll see in future posts, some of my other 11×11 designs do have more pieces promote to something present in the initial array.

In my defence, many Shogi variants have promotions that don’t appear in the initial position, including Shogi itself (the Dragon King/Dragon Horse); here I’ve just extended that to its logical extreme!

Gameplay

Shinjuu Shogi is a big game, much bigger than standard Shogi, but much like Chu Shogi and its larger cousins, a few games will quickly solidify the piece movements in your mind. The major conceptual obstacle to overcome is the substantially increased asymmetry in the moves compared to standard Shogi; many pieces in this game have odd mixes of stepping, jumping and sliding moves. To play this game well, players must master all these distinct movement modes for these pieces, and this can be a challenge at first.

I was careful to select pieces that all have weaknesses in certain directions; we have no equivalent of the Queen here. Many pieces in Shinjuu cannot move in some directions at all, and even the strongest pieces have some directions with limited movement capability, which opens them up to long-range attack. These weaknesses mean that pieces generally have to be used in concert for maximum effect, and no one piece is able to fully dominate the board. In addition, these weak spots open up opportunities for fun tactics — a clever drop in an opposing piece’s blind spot can be an effective way to regain the initiative.

The general feel of the game is high intensity, and very dense. Despite the piece density being about the same as modern Shogi — in modern Shogi 40 of the 81 squares are occupied at the start, and here 58 of 121 are occupied — the game feels more dense, perhaps because the sheer number of pieces creates the impression of being constantly surrounded by threats. However, in practice the game board offers plenty of space for manoeuvre, and rarely will a player struggle to find a way to improve the positions of their pieces. In addition, once players hold a few pieces in hand the number of possible moves each turn escalates massively (over 500 possible moves is not uncommon!). This means that strategic and positional thinking is critical, because in a complex middlegame position it will be impossible to calculate out all the possible tactical variations your opponent may choose. Players have to survive by developing sound positional fundamentals and maintaining whole-board vision.

Unfortunately, I’ve yet to have the opportunity to play this game against strong opposition, but in my test games so far I’ve found a typical game will last between 200-300 moves. This is substantially more than Shogi and Wa Shogi, but on a similar level to Chu Shogi. This game length is right around the 250 move mark that I was aiming for throughout the design process. The typical game of Go is about 250 moves long, and something like ~50 million people play Go on this planet, so I felt that was a good target to aim for that would satiate my thirst for long, involved games but would not feel particularly excessive. On rare occasions I had games just over 400 moves long, but in subsequent analysis I found they could’ve ended much sooner with some sharper play.

On the whole I’m sure opinions will vary on this game and my design principles, but so far I enjoy the result. The game is big, complex, and jammed full of possibilities, but it also feels like Shogi and never slows to a crawl. The larger board and longer games create an expansive feel, and the thematic pieces drawn from ancient Shogi help create a quirky narrative feel in the game. Realistically I suspect very few people will ever play this game, but if nothing else I feel I’ve made progress on my design goals and have learned a lot in the process.

The Pieces of Shinjuu Shogi

Shinjuu Shogi is a big game, and given that I want it to be a showcase for unusual historical Shogi pieces it contains few pieces that will be familiar to modern Shogi players (just the King, Pawns and Gold Generals). That means there’s a bit of a learning curve, so I’ve put together a quick reference sheet, where each piece is paired with its promoted form:

A PDF version for printing or reference is available here. Note that the top of the sheet also has some reminders of the pieces with special moves, which are various types of leaping moves.

The four shinjuu themselves are perhaps the hardest pieces to remember initially. However, it may help to realise that the moves of the Turtle Snake and Vermillion Sparrow are related — just take the forward slide and backward step of the Turtle Snake and invert them, and you have the Sparrow! Likewise, the White Tiger has the same move as the Blue Dragon, just rotated 90 degrees counterclockwise, and the same is true of their promoted forms. The Turtle Snake and Vermillion Sparrow promotions are easy to remember too, as they both simply replace the backward diagonal steps with unlimited slides, while keeping the rest of their unpromoted moves the same. Similarly, the promoted White Tiger and Blue Dragon replace one two-step move with an unlimited slide.

Players familiar with large Shogi will notice that some of the promoted pieces here are quite powerful, in particular the Golden Bird and its ability to leap over up to 3 pieces while sliding diagonally forward. However, promotions are more difficult to achieve here than in the ancient games, thanks to drops; throughout the game the number of pieces on the board remains largely constant, so any piece attempting to promote is likely to encounter a heavily-guarded promotion zone. Attackers should be more cautious about pushing for promotion here, and spend time setting up substantial weaknesses in the opponent’s defensive formations beforehand.

The generally stronger promotions mean that minor pieces are more valuable in Shinjuu than in standard Shogi. In particular the Gold Generals gain six unlimited sliding moves when they promote, but they’re also very useful for defending one’s King so deciding when or if to promote them is often challenging. Promoting a Gold General commits you to the attack, because it can only retreat one square. Meanwhile, the Kirin and Phoenix are interesting to use in this game, as their unpromoted moves include very useful leaps. Their promoted forms are dangerous aerial attackers, given they can leap 3 squares over defending pieces. Beware of these pieces when defending; the King will need escape squares, or you may end up in a smothered mate situation.

Of the major pieces, the Fragrant Elephant and White Elephant are perhaps the most dangerous. Their standard moves are strong already, but in promoted form they become highly mobile as well. Players must always be aware of any Elephants attempting to promote, and in the endgame having a couple of Pawns in hand to buttress the King’s castle against airborne Golden Bird threats can be helpful. The Great Standard is very strong but also has limited retreating moves, plus it is one of the few pieces that can slide sideways and is therefore useful for protecting the promotion zone. The White Dragon can also serve well in this role, while the Blue Dragon can guard against edge attacks and support advancing Pawns. The Turtle Snake and Vermillion Sparrow are perhaps the most active attacking major pieces, as their forward-facing slides allow them to generate a variety of long-range threats, and in promoted form they can retreat very effectively too. The shinjuu have fairly mild promotions in general, so players may be more willing to use them for daring sacrifices; in contrast, handing your opponent extra Elephants can be seriously risky!

At this early stage in the game’s life it’s difficult to judge the best approach to defence. One’s instinct may be to surround the King with a thick wall of defensive pieces, but in practice this can be very dangerous. Leaping pieces can bully the King around even from outside your defensive structure, and handing the initiative to your opponent without generating counterplay may allow them to dominate elsewhere on the board and develop opportunities for deadly promotions. My approach has been to shift the King to one of the flanks of the board, keeping him guarded by the Leopards, Golds, White Tiger and Great Standard. My frontline attackers have been the Turtle Snake, Vermillion Sparrow, and Fragrant Elephant, with the Kirins and Phoenixes providing support.

On the whole, the pieces in this game have unusual moves, and don’t fit cleanly into our pre-existing notions of what we might do with more typical Chess or Shogi pieces. I’ve found it enjoyable to try and understand the best use of these pieces, as each has a distinct personality and clear weaknesses that must be taken into account. Over time I hope to deepen my understanding of how to use these pieces effectively.

A Closer Look

Let’s take a moment to examine the last portion of one of the sample games shown in the GIFs above. This game was played against the AI (120 seconds/move thinking time), and playing as Sente I won after 181 moves:

Bear in mind I’ve played this game a lot, so I’m quite familiar with the AI’s foibles, and I’d emphasise that Gote’s defence is not optimal. Nevertheless, hopefully this brief discussion of a sample endgame can give you a bit more of a idea of how the game plays.

In this game I decided to press home my advantage and play for the win around move 139:

Until this point I’d been focused on securing the centre of the board, with an eye toward prying open Gote’s position on the left side. Gote’s right flank has the two Kirins and several Dogs providing additional protection, so the more lightly-defended left offered a bit more of an opportunity. I’d also developed a strong material advantage, with six pieces in hand ready for dropping.

I started my plan by pushing the freshly-dropped Pawn on d6 forward, while Gote responded by advancing pieces out of the right flank to pressure me from the other side:

On move 145 my Pawn has promoted to Tokin, putting pressure on Gote to respond. Gote elects to exchange the Vermillion Sparrows, so I recaptured with my Fragrant Elephant, which Gote then took with their White Tiger. Rather than take that, I elected to press the Tokin forward, punching a hole in Gote’s defensive formation around their King:

Here the AI elects to press forward with its White Tiger, threatening to fatally weaken my Pawn line in the centre. I prevent this by taking with the Turtle Snake, and then the AI attempts a distraction by dropping a Fragrant Elephant near my King. I ignore this and take the Ferocious Leopard with my Tokin, then sacrifice my Turtle Snake in exchange for the Gold General, creating a serious weakness in Gote’s defences:

The White Tiger now pins the Phoenix to Gote’s King, and it’s time to start hurling my massive material advantage into the meat grinder. I do have to be cautious, because Gote does hold several good defenders in hand, and if I allow Gote any room to breathe they could still cause trouble around my lightly-defended King.

Gote proceeds to attempt exactly that, taking my Gold General with their Fragrant Elephant and forcing me to retake, then dropping a Turtle Snake in prime position in the centre. However, this is fine for me, as I can take Gote’s Phoenix with my White Tiger, forcing a recapture with the Kirin and opening a diagonal toward Gote’s King. Rather than exploit this immediately I drop a White Elephant next to the Phoenix, which can’t attack orthogonally adjacent pieces, and promote to a deadly Golden Bird:

This forces Gote to drop a Gold to block, and then I can drop a Vermillion Sparrow on that key diagonal. Gote is now firmly on the back foot, with only two droppable pieces left, and it’s time for me to end the game in a hail of drops.

There’s no way out for Gote, and their King ends up checkmated by a deadly combo of Mountain Witch and Great Elephant:

Granted, I’m no Shogi master, and the AI is struggling on without a specialised evaluation function for this game, but hopefully you can see that Shinjuu offers interesting checkmating sequences that feel very Shogi-like. Despite the larger board, bigger armies and wackier pieces, the general strategic themes feel very reminiscent of the modern game. Battles for central control, prying open weaknesses in the position with drops, and building up pieces in hand for a final assault — all these aspects of Shogi play are still present.

The moment-to-moment tactics do feel distinct though, as the pieces are generally quite powerful, so choosing the right moment to attack is crucial. Pieces like the Elephants can protect a large number of squares, so using your leaping pieces and strong promoted pieces is important to get around solid defences.

The other sample game has an example of this aspect. In that game, a crucial moment happens on move 250:

Here Sente has had its King forced into the centre, but it’s completely cocooned by a deep fortress of strong defenders. However, Gote drops a Phoenix and promotes to Wooden Dove, which puts the King in check via its 3-square leaping slide! This shows us the danger of having a dense fortress — the King can be forced out via leaping attacks, and in this case if the King hadn’t had this one escape square, this move would have been checkmate.

From there, Gote launches a vicious attack that completely bypasses Gote’s massive central castle, and Sente’s desperate counterattack fizzles due to Gote’s more flexible defensive structure on the back ranks. As Sente’s offensive splutters and dies, Gote seizes the moment and forces an unusual checkmate with Blue Dragon, Great Dragon and Fierce Eagle:

So, while some basic Shogi principles do transfer over, the presence of many strong pieces and leaping attackers changes attack and defence significantly. While Sente could have defended better here, that check on move 250 was a nice refutation of Sente’s attempt at King safety, and once the King was isolated on the back ranks it was difficult to defend against Gote’s assaults. Gote, in contrast, kept the King out of the centre with a looser defensive formation, enabling them to absorb counterattacks well and maintain more escape squares to protect against leaping attacks.

In any case, I hope that some Shogi fans out there might be convinced to give this game a try, as I’d love to see what strong players could do with this game. On more than one occasion I’ve had very exciting endgame attacks in this game, where the path to victory was a spectacular sequence of 20+ drops with both Kings getting pushed all over the board. A tense battle between two strong players could provide quite a spectacle!

Lessons Learned

When I started working on this game, I hoped that I’d have a chance to really test some of the standard assumptions one encounters in discussions about Shogi variants. There are a couple of widely repeated concerns I’ve seen relating to drops-based variants:

Games with drops should have weak pieces — This point is often justified by pointing at Shogi, Tori Shogi and Wa Shogi, all of which are excellent games and all of which have generally weak pieces. However, a few other examples of larger drops-based games like Okisaki Shogi and Futashikana Shogi seem to show that more powerful pieces don’t break the game, and of course Crazyhouse uses the strong Chess army on the tiny 8×8 board and is still great fun to play (though White has a nice advantage).
Drops-based games won’t work on large boards — I’ve seen this brought up often in passing; people will say things like ‘imagine playing 12×12 Chu Shogi with drops, that would be preposterous!’ Of course they’re completely right about this, but I wasn’t sure that the general point follows; after all, Chu Shogi is completely crammed with super-powered pieces and the start position is much higher density than modern Shogi (66.7% vs 49.4%).

Having spent ridiculous amounts of time on Shinjuu Shogi at this point, and a number of related drops-based variations during testing, I’ve convinced myself that both these issues are not as bad as they seem and the pitfalls they identify can be avoided.

Firstly, powerful pieces seem quite at home in drops-based games, so long as they have weaknesses that prevent them from dominating the board. In Shinjuu, I accomplished this by using pieces with clear blind spots. The selection of weaker pieces helps here, and ideally some of those pieces should provide an effective countermeasure to the strong pieces. Okisaki and Futashikana Shogi replace the Shogi Knight with the strong Chess Knight, which I think works well because the Knight can attack the Queen from squares it can’t see (and conversely, Knight + Queen is a potent attacking combination).

As far as large boards go, again I found this to be a matter of balance and piece density. The general approach in large drops-based variants seems to be to lower the density relative to modern Shogi, but I’ve found it equally playable to keep the piece density around 50%. Having done extensive testing on 11×11 with anywhere from 23 to 33 pieces per player, I found that lower densities tended to lead to less exciting tactics and somewhat shorter games, while higher densities were packed with tactical shots but were either overly long (due to an overabundance of defensive resources) or overly short (due to an overabundance of powerful pieces that could checkmate with a single drop), depending on other factors like piece selection. The sweet spot was right in the middle, at or near the 50% density of modern Shogi.

I’ve since begun experimenting with a 12×12 drops-based game called Yuudai Shogi (Grand Shogi) which follows these principles, and the results have been interesting:

Yuudai Shogi initial position with traditional kanji pieces.

The sample game above is actually unusually long; most test games so far have been under 300 moves (against AI with 120 seconds of thinking time). The piece density is much less than Chu Shogi (precisely 50% in Yuudai), and the piece selection is very different as well. Again I selected pieces with limitations, and there are no super-powered monstrosities like the Lion of Chu Shogi.

This game is still very much in development, but so far it’s quite playable. Games are over in a reasonable amount of time, given the board size and number of pieces, and play maintains momentum and intensity despite the huge armies protecting each King. I imagine that between two very strong players, some games might top 500 moves. Having said that, if someone is willing to spend the time necessary to master a huge 12×12 game with 35 types of pieces, I suspect they’ll have the patience needed to fight such an epic battle!

I should stress that I’m still at the early stages of these experiments, and I may end up finding that there are pretty hard limits on board size or other elements when building drops-based games. But for the time being at least, I think there is a lot of promising and mostly untapped design space here that should be investigated further.

If I were to revise the general wisdom on drops-based games, I would just soften it a bit, and say that when building games of this type on large boards with strong pieces, just be prepared to do a lot of work. Chess is a generally remarkable game category in that the basic framework remains robust and playable even when we use extremely powerful pieces and/or go nuts with board sizes and other aspects (Tenjiku Shogi is a fine example of this phenomenon). For better or worse, this has allowed Chess variant design to be pretty wide open, given that one can place just about anything on the board and the resulting game will probably still work. But when we introduce drops and pieces keep coming back to life, suddenly things get a lot more brittle, and relatively small changes can have large effects.

Given the nature of drops, perhaps this isn’t so surprising; a capture in a drops-based game constitutes a significant swing in material value between the two players, and allowing any piece to suddenly materialise nearly anywhere on the board necessarily amplifies its potential impact. Combine that with complicated positions allowing hundreds or even thousands of possible moves (when using large boards), and we can see why certain non-linearities of effect start coming into play.

So, at this point my (very) basic suggestions are:

Drops-based games on large boards need armies where pieces have weaknesses and blind spots (note that pieces having weaknesses isn’t the same as a piece being weak!).
Piece density should be at or around 50% to avoid overcrowding and games dragging on too long, or ending too suddenly under a hail of super-powered drops.
Even small changes in the composition of the armies can have large effects when drops are involved, so when you make a change, test, test, and test again!

Over time I hope to build on these principles and develop more detailed tips, but for now, I hope at least some other Shogi variant designers might be inspired to give larger drops-based games a try and share their experiences.

Of course, these ideas are built on the assumption that we will keep drops exactly as they are in Shogi, but this doesn’t need to be the case. What might happen, for example, if we took Chu Shogi, chopped out a few pieces to reduce density and added drops, but Lions, Free Kings, Dragon Kings and Dragon Horses were permanently eliminated from the game when captured? Or what if we introduced a system like Kamikaze Mortal Shogi, where captured pieces degrade in power until eventually they fade away completely? Or what if we restrict drops to only one’s own half of the board? Or what if we allowed only a small number of captured pieces to be held in hand for drops, with any additional captured pieces being removed from the game instead? So far as I know, few of these ideas have been tried with large-board drops-based variants. At this point I’m fairly convinced that, with a bit of clever engineering, drops could be used in nearly any size of Shogi variant.

Next Moves

Now that testing is mostly done, I plan to release Shinjuu Shogi in a future Ai Ai update. At that point, I’d welcome any feedback from players, and of course I’d be happy to play games with readers of this blog via Ai Ai’s online functionality.

During the construction of Shinjuu Shogi I’ve learned a great deal about the challenges of designing larger drops-based Shogi variants, so I’ve been applying this experience to my development of 12×12 Yuudai Shogi. Over the next few months I plan to put this game through an intensive testing regime as I did Shinjuu Shogi, and hopefully at the end of all that I’ll have a game worthy of release.

While working on Shinjuu I also constructed several other 11×11 modern Shogi variants, all of which incorporated pieces from Taikyoku Shogi. Each game focuses on a particular thematic category of pieces, like dragons, cats, and so on. I’ve been testing these in tandem with Shinjuu, and have found them to be fun introductions to the wild piece selection of the enormous Taikyoku Shogi. In the future I will feature these games as well, in particular Shouryu Shogi (Rising Dragon Shogi) and Puppy Shogi, which I believe to be the most promising games.

Tagged 11x11 Shogi, Shinjuu Shogi, Shogi, Shogi Variants

May 13 2021

4 Comments

Chess, Games, Shogi

Ancient Shogi Revival, Part II: The Big Ones

UPDATE 6 Nov 2021 — More sample games updated — Dai Dai Shogi, Tai Shogi, Mini Tai Shogi.

UPDATE 25/10/2021 — Some of the sample game GIFs on this page broke, possibly from WordPress again changing the size limit for displayed images. I’m slowly replacing the sample games for Maka Dai Dai Shogi, Tai Shogi and Mini Tai Shogi with new, smaller GIFs. These games were generated with much longer thinking times (120 seconds) so the games are also higher quality.

USEFUL TIP: WordPress handles GIFs in a weird way. When you want to see/download the full-size GIFs, click the image and then click the (i) button, and finally click the link to view the full-size GIF in another tab.

Since my previous post on our addition of multiple variants of Shogi to the Ai Ai general game-playing software, Stephen and I have been hard at work implementing even more ancient Shogi games. If you thought the giant 15×15 Dai Shogi was over-the-top, you’ll be amazed what we’ve brought to you this time!

Before I show off what we’ve done, a few points to keep in mind when you download the new Ai Ai version with all these amazing games:

We’ve done a huge amount of work in a relatively short period of time, and have done everything we can to catch mistakes and bugs, but some bugs will still be present! If you find a bug or incorrect piece movement or something, please do point it out to us, and we’ll do our best to resolve the problem. Also, some rules are still not quite there (repetition rules, for one), so please be patient.
The AI is very much a work in progress! Some of these games are truly gigantic, and as a result getting strong play out of the Shogi engine in Ai Ai is really, really difficult. When you do play against the AI, be sure to give it plenty of thinking time; at an absolute minimum, give it 30 seconds per move for the 16×16/17×17 games, 1 minute for 19×19, and 2 minutes or more for 25×25. If you have an old computer with a slow CPU you may need to amp those times up significantly. If the thinking times are too low, you may find the AI repeats moves a lot as it struggles to find useful continuations.
For those games which have a playing community and multiple possible rulesets (Tenjiku Shogi), we have not attempted to resolve any long-standing rules disputes, but instead have opted for being comprehensive. All the games have options to choose different rules interpretations, piece movements, etc. Essentially I decided to include a rule proposal or piece movement when that interpretation had been played before, and/or had some historical plausibility, and tried to remain neutral on the long-standing rules disputes in some of these games. The hope is that players may try all these different variations in Ai Ai, and hopefully use those experiences to choose the best ruleset to play as a community.

With that out of the way, let’s get to the games! For each one I’ve included some details about the options available to players in Ai Ai. At the end of the article there is an FAQ section, so please check that for some additional useful tips and tricks for using Ai Ai, and some general questions about our Shogi implementations.

Tenjiku Shogi (16×16)

Tenjiku Shogi initial position with kanji pieces.

Tenjiku Shogi (天竺大将棋, or Tenjiku Dai Shogi in Japanese) is a remarkable historical Shogi variant that is one of the most popular of these ancient games among modern players (alongside Chu and Dai Shogi). Tenjiku Shogi is played on a 16×16 board with each player starting with an army of 78 pieces of 36 different types. The game stands out not only among Shogi variants, but among Chess-like games in general for its extreme tactical sharpness and super-powered pieces. The word ‘Tenjiku’ means ‘Indian’ but is more often translated as ‘exotic’, because at the time of Tenjiku’s invention (sometime in the 16th-17th century, most likely), India was seen as a mystical and exotic place, the birthplace of Buddhism and the home of marvellous creatures like tigers and elephants. Tenjiku certainly lives up to its name, and has some very unique pieces that give the game a distinctive flavour:

Fire Demon — for a start, this incredibly powerful piece is very mobile; it can slide unlimited squares in six directions, or take three successive King-like steps in any direction to dodge around obstructions. But much more notable is its ability to burn opposing pieces — when the Fire Demon ends its move, all adjacent enemy pieces are immediately removed from play. This means the Fire Demon may kill up to eight pieces in a single turn (one on its destination square, and seven in the surrounding squares). This ability even functions on the opponent’s turn; any enemy piece that ends its move next to your Fire Demon is immediately burned and removed from play, and that doesn’t count as your turn! If your opponent lands their Fire Demon next to yours, their Fire Demon is burned, and it doesn’t get to burn any of your pieces before it is removed from the board. Fire Demons can still be captured by any piece that lands directly on its square.
Range-Jumping Generals — Four pieces in Tenjiku, the Great General, Vice General, Rook General, and Bishop General, have the ability to make range-jumping captures, where they may leap over any number of friendly or opposing pieces to land on an enemy piece and capture it. To keep this amazing ability under control, these pieces are subject to a hierarchy, and may not jump over pieces above them in that hierarchy; this allows players to block these powerful jumps with careful defensive placement. In the two main Tenjiku rulesets there are two different interpretations of this ability; more on that in the discussion of game options below.
More powerful Lion pieces — Tenjiku includes all the pieces present in Chu Shogi including the remarkable Lion, which may move and capture twice in a turn. In Tenjiku the Lion can promote to an even more powerful piece, the Lion Hawk, which may move as a Lion or a Bishop. Tenjiku also includes the Free Eagle, a piece that may slide an unlimited number of squares in any direction, or may make a Lion-like double-move but only diagonally.

Combine all these powerful pieces and you get a game that despite its size is remarkably fast-paced and violent, with deadly tactical combinations possible right from the beginning of the game. Most large Shogi variants have quite long and subtle openings, but in Tenjiku one opening mistake might lead to an embarrassingly early checkmate. These unusual properties have enabled the game to develop a small but dedicated Western playing community, and as a result numerous resources are available for prospective players, including opening guides.

Sample game of Tenjiku Shogi (68 moves, PBEM ruleset).

Rulesets and Options

Tenjiku Shogi has had a lot of attention over the years since it was introduced to the West in the 1980s by George Hodges. Unfortunately, as with many of these ancient games, some important rules questions remain unresolved. Modern players have developed two main rulesets that are in use, both of which are available in Ai Ai:

Richard’s PBEM Server ruleset: the yearly Tenjiku Shogi Championship tournament is played on Richard’s PBEM Server, and uses this ruleset. In brief, the main distinguishing features here are: Fire Demons may slide unlimited squares diagonally or vertically; range-jumping generals may capture Kings or Princes while jumping, allowing for some very early smothered mates to occur; and the Heavenly Tetrarchs do not have a vertical sliding move (and in fact use an odd set of movements that seems to be a mistake, so you may want to use the TSA Tetrarch variant instead). Early checkmates are very common in this ruleset.
Wikipedia/Chess Variant Pages ruleset: these rules have been promoted by HG Muller, and produce a somewhat less violent Tenjiku experience than the PBEM ruleset. In this ruleset: Fire Demons may slide unlimited squares diagonally or horizontally; range-jumping generals may not capture Kings or Princes while jumping, eliminating the early smothered mates; and the Heavenly Tetrarchs have a vertical sliding move, making them a clear upgrade over the Chariot Soldiers from which they promote.

Various spirited arguments have taken place, and continue to take place, over these key rule interpretations. In Ai Ai we have chosen instead to implement both options, to give players a choice of how they want to play — simply load TenjikuShogi(PBEM).mgl for the PBEM ruleset, or TenjikuShogi(WP).mgl for the Wikipedia/Chess Variant Pages rules. In the hope of helping the community to resolve these rules discussions, we have also included a customisable version (TenjikuShogi(Custom).mgl), which allows players to customise their ruleset with the following options:

Fire Demon move — you may choose whether the Fire Demon slides diagonally and vertically (PBEM version), or diagonally and horizontally (WP version).
Range-Jumping Generals — you may choose whether they can capture the Royal pieces (King and Crown Prince) by jumping (PBEM) or not (WP).
Heavenly Tetrarchs move — you may choose from four (!) different move options for the Heavenly Tetrarchs:
1. PBEM move — no vertical slide, may never move to the eight adjacent squares, may capture without moving on adjacent squares, adds a three-square vertical jump (which seems like a mistake)
2. Wikipedia/Chess Variant Pages move — vertical slide, may never move to the eight adjacent squares, may capture without moving on adjacent squares
3. TSA move — the original move advocated by The Shogi Association — no vertical slide or vertical jump, may never move to the eight adjacent squares, may capture without moving on adjacent squares
4. Sho Shogi Zushiki move — vertical slide, may never move to the eight adjacent squares, and may NOT capture without moving on the adjacent squares
Lion Hawk move — you may choose two variants of the Lion Hawk:
1. TSA move — the Lion Hawk does NOT have Lion Power, but instead may move as a Bishop or step twice as a King in any direction, but may only capture once during this two-step ‘area move’
2. Modern move — the Lion Hawk moves as a Bishop or a Lion, with full Lion Power
Free Eagle move — you may choose two variants of the Free Eagle:
1. TSA move — the Free Eagle may move as a Free King, or may jump two squares orthogonally
2. Modern move — the Free Eagle may move as a Free King, or may make two successive one-square diagonal steps, which can include making two captures, capturing an adjacent piece and moving back to the starting square (igui capture), or passing a turn by moving to a diagonally adjacent square then back to its starting point.
Allow Zone-Passing — you may choose whether or not to allow zone-passing; if zone-passing is allowed, that means that Lion-Power pieces may promote if they make a Lion-style move into the promotion zone and immediately back out again on the same turn.
Water Buffalo promotion burn — if Water Buffalo promotion burns are allowed, that means that when a Water Buffalo promotes to Fire Demon, it may immediately burn all adjacent enemy pieces on the move where it promotes. This is suggested in the Wikipedia/Chess Variant Pages ruleset.

That’s a lot of options! I’m 100% sure that some members of the Tenjiku community would prefer that I adopted only their preferred ruleset/piece movements, but again I have tried to avoid wading into any long-standing rules disputes here. I opted to go over all Tenjiku-related materials I have and simply include any rules/movements that have some historical backing, or have been played before, or advocated seriously as a proposed change to the rules, so that players may try them all and make an informed choice. I did decide not to include the original TSA rules for the range-jumping generals, however, as these have been shown to give an easy win to Sente.

Promotion Rules and 50 Move Rule

Note that I have decided to offer all three main Tenjiku variants with the Chu Shogi promotion rules; this is mainly because there seems to be some momentum lately to adopt these rules in the PBEM Server version, and the Japanese Wikipedia rules state the Chu Shogi promotion rules are applied in this game. If anyone wishes to use modern Shogi promotion rules instead, simply open the appropriate .mgl file in a text editor, and find a line that looks like this:

“promotionRule” : { “rule” : “ChuShogi”, “allowIguiPromotion”:false },

Remove the “rule” : “ChuShogi”, part and you will be using modern Shogi promotion rules.

I also decided not to include any equivalent to the 50-move rule in Chess, mainly because these rules are a modern invention and definitely not part of ancient Shogi, and also because we have no idea what a good move threshold would be in these huge games. However, if the community does want to use a 50-move rule equivalent, this can be added to any Shogi variant by opening the appropriate .mgl file, finding the section called “endCondition”, and within the square brackets adding another line that looks like this:

{ “condition”:”boredom”, “who”:”all”, “result”:”draw”, “moves”:50 },

Simply change the move number to your preferred option, and that’s it!

In any case, I’m a strong believer that debating game rules without playtesting them is pretty pointless, so I’m hoping that having all these options available will help the various rules debates to eventually get resolved. With these different rules variations now playable online as well as against the AI, players may thoroughly test them and decide together how they want to play Tenjiku in the modern age.

Tenjiku Sub-Variants

For players who are interested in playing Tenjiku but find the full-sized game intimidating, we’ve also included two smaller modern variants of Tenjiku Shogi:

Nutty Shogi (13×13)

Nutty Shogi initial position with kanji pieces.

Nutty Shogi was invented by HG Muller in 2015, and is a very enjoyable reduction of Tenjiku Shogi to a more compact 13×13 board. All rules remain the same, so it’s a straight subset of the full game. In this implementation players may choose from the options present in the custom Tenjiku Shogi version, in order to match their preferred ruleset for the larger game. Note that the game seems to have been designed to use the Wikipedia/CVP rules, so I recommend using those options.

Makyou Shogi (12×12)

Makyou Shogi initial position with kanji pieces.

I’m a fan of Nutty Shogi, but find it mildly inconvenient in that no historical Shogi variants use a 13×13 board, so it’s not easy to play physically even with my collection of Shogi variant pieces and boards. So I created Makyou Shogi, a reduced version of Tenjiku designed to fit on a 12×12 Chu Shogi board. Makyou is a Japanese word meaning ‘demon-infested place’, which felt appropriate for this tight board packed with powerful pieces! Note that the piece mix is a bit different from Nutty Shogi. Also, this game is still being tested, so the starting array may change over time.

Makyou Shogi allows players to tweak any of the rules/piece options present in the Tenjiku Shogi customisable implementation; having said that, I strongly recommend using the Wikipedia/CVP rules in this game, as the PBEM pieces make the game too tactical with little room for strategy.

Dai Dai Shogi (17×17)

Dai Dai Shogi initial position with kanji pieces.

With Dai Dai Shogi, we enter the realm of the truly gigantic Shogi variants. Players start the game on this huge 17×17 board with 96 pieces each of 64 different types (4 additional types appear only via promotion). Among those pieces are the ultra-powerful hook-moving pieces — the Tengu and the Hook-Mover — which may make two successive moves as a Bishop or a Rook respectively, making a right-angle turn after the first one (but may only capture once).

Dai Dai Shogi is the smallest of the ancient Shogi games to use a promotion-by-capture rule. Instead of promoting upon reaching the enemy camp, pieces in Dai Dai Shogi promote immediately after they capture any opposing piece (if the piece has Lion Power, the promotion happens at the end of their complete move). Promotion by capture is mandatory and cannot be deferred. Unusually for a Shogi variant, most pieces in Dai Dai Shogi do not promote, including Pawns; this relative lack of promotable pieces together with the promotion-by-capture rule gives the game a quite different feel from the other historical Shogi variants. The promotion-by-capture rule has a profound impact on tactics, too, as players must now be careful that any capture exchanges don’t leave the opponent a strong promotion at the end of the fight.

The Dai Dai Shogi starting array is packed with pieces and very asymmetric, with many pieces only appearing once rather than in pairs. The initial position is also arranged quite differently from the other large Shogi variants (with the exception of Tai Shogi, to an extent) — the strongest pieces are at the back of the player’s army, rather than the front. This means opening play is quite slow and subtle, as players try to develop their pieces soundly without leaving any easy captures for the opponent to use for promotion, while also trying to free their most powerful pieces. The endgame can become pretty hectic, as the hook-moving pieces finally come out to play and their incredible mobility makes them a deadly threat. All told the game is thoroughly engrossing, deeply strategic and yet filled with rich tactics:

”This is the writer’s personal favourite of the [large Shogi variants], owing to the tremendous variety of pieces, the wealth of strong pieces and weak pieces with strong promotions, and the asymmetrical opening setup…. What often happens in practice is that the entire board opens up into the most complex tactical struggle seen in any of the forms of Shogi.” (R. Wayne Schmittberger, writing in Shogi Magazine in 1981)

Rulesets and Options

Fortunately, unlike Tenjiku Shogi there are relatively few major rules disputes in Dai Dai Shogi, if only because very few people have played it. As a result our implementation has just two main incarnations: one which includes the troublesome Great Elephant piece in four variations (DaiDaiShogi(complete).mgl); and another which excludes the Great Elephant piece entirely, which apparently is the case in two historical sources (DaiDaiShogi(noGE).mgl). In both versions the player may choose between two variations of the Furious Fiend’s move, as well.

This version of the Great Elephant may leap over up to three pieces when sliding.

Alongside the Elephant variants described in the translation notes article, in this final version we also included a variant move sometimes used in Tai Shogi, which allows the Great Elephant to move as a Lion Dog or slide up to 5 squares horizontally or diagonally backward. This move is recommended by the Japanese Chu Shogi Association (Chu Shogi Renmei).

Sub-Variant: Cashew Shogi

Cashew Shogi initial position with kanji pieces.

Invented by HG Muller in 2015, Cashew Shogi is a reduction of Dai Dai Shogi onto a smaller 13×13 board. This variant includes most of the characteristic pieces of the larger game, but substantially reduces the number of moves one has to remember. Despite the size reduction, the AI vs AI test games I’ve tried are often not that much shorter than the full-sized games of Dai Dai Shogi, and sometimes are substantially longer! I suspect this is mostly due to the size difference, however; the much larger board size in Dai Dai Shogi gives the AI a hard time, so it tends to make more serious blunders during play. In Cashew Shogi the AI can find stronger moves, and is less likely to blunder its way into a quicker loss.

Our Cashew Shogi implementation allows players to choose their preferred form of the Great Elephant and Furious Fiend, as in Dai Dai Shogi.

Maka Dai Dai Shogi (19×19)

Maka Dai Dai Shogi initial position with kanji pieces.

Let’s get my biases out there straight away — Maka Dai Dai Shogi is a very cool game, and I’m overjoyed that it’s now playable in Ai Ai. This is a truly immense game, played on a 19×19 board with 96 pieces of 50 types in each player’s starting army, and it uses a promotion-by-capture rule like Dai Dai Shogi (more on this below). What makes Maka Dai Dai Shogi stand out is the presence of several unique mechanics and pieces that give this enormous game the feel of a giant mythical battle; this is no coincidence, as the game is clearly heavily influenced by Buddhist mythology:

The All-Powerful Emperor — unlike the other Shogi games, in Maka Dai Dai the King can promote! If your King captures an enemy piece, he may promote to Emperor, perhaps the most powerful piece in any Chess-like game. The Emperor can instantly jump to any square on the board, including squares occupied by enemy pieces, but it may not enter protected squares or capture a protected enemy piece. Checkmating the Emperor seems impossible, but the hook-moving pieces can make it happen.
The Deva/Dark Spirit/Teaching King/Buddhist Spirit — At the start of the game the Kings are flanked by a Deva and a Buddhist Spirit, two incredibly weak pieces with very awkward asymmetric 1-square moves. But when a Deva captures an enemy piece, it becomes a Teaching King, a super-powered piece that may move as a Lion Dog or a Free King; likewise, the Dark Spirit becomes a Buddhist Spirit, which moves as a Lion or a Free King. More intriguingly, these pieces are contagious — that means that if an enemy piece captures your Deva or your Teaching King, it immediately becomes a Teaching King, or if it captures your Dark Spirit or Buddhist Spirit it immediately becomes a Buddhist Spirit. Consequently these pieces are very difficult to eliminate from the board permanently, unless they are taken by another Teaching King/Buddhist Spirit or by a royal piece (King, Emperor or Prince, who ignore the contagious aspect and simply promote normally). Some Shogi historians believe the Buddhist Spirit and Teaching King may represent the Buddha and the Lotus Sutra, respectively.
Promotion by Capture — as in Dai Dai Shogi, pieces in Maka Dai Dai Shogi promote when they capture something, so there are no promotion zones (or, alternatively, we can consider the entire board the promotion zone). However, there are two variants of this rule: in one version, suggested by Wikipedia and the Chess Variant Pages, the capturer may choose whether to promote or not, unless the captured piece is promoted, in which case they must promote; in the other, suggested by the TSA rules pamphlet and Japanese Wikipedia, pieces must promote when they capture, as in Dai Dai Shogi. In either case, Maka Dai Dai moves away from the Dai Dai Shogi model and allows nearly all pieces to promote, more like the other historical variants. Many short-range pieces promote to ‘Free’ versions of themselves, which move in the same directions but extend all one-step moves into unlimited sliding moves.

These elements combined give Maka Dai Dai Shogi the strategic depth and nuance of the other large games, but punctuated with moments of extreme dynamism: the Emperor can teleport around the board savaging his enemies; the two powerful, mystical spirits stalk the board and never stop hounding one player or the other; and even the weakest pieces can promote into powerful board-spanning threats. I honestly can’t recommend this game enough, it’s huge and crazy but very very interesting and enjoyable to play, and just packed full of cool pieces. Here are my picks for the top ten coolest pieces in Maka Dai Dai Shogi, from strongest (Emperor) to weakest (Free Bear):

Fortunately, it seems I’m not the only one who developed a bit of an obsession with this game. In the historical documents there is a long chant given that helps players to remember the opening setup, which suggests the game was popular enough that players developed these kind of mnemonics to help them get the game started more quickly. A research group in Osaka, led by Professor Tomoyuki Takami, has been studying this game for years, generating a lot of lively debate about its origins, influences and rules; Professor Takami has also invested a lot of effort in promoting the game. I have a fervent hope that one day these pockets of interest in Maka Dai Dai Shogi will blossom into a full-blown playing community, and this Ai Ai implementation is my attempt to help that process along.

As a side note, Prof Takami’s group has developed a set of rules for what they believe to be an earlier form of Maka Dai Dai Shogi, which they call Maka Dai Shogi. This game also seems very interesting, but we haven’t included this in Ai Ai because it would involve programming numerous variant rules and pieces, and the rules are not stable and seem to change fairly frequently as Prof Takami finds new evidence in the historical documents. At some point we may include it, when I have time to reach out to Prof Takami and get a comprehensive set of rules.

Rulesets and Options

Maka Dai Dai Shogi has relatively few options to worry about when starting a game:

Promotion Rule — players may choose whether promotion on a capture is compulsory, or whether it is generally optional but becomes compulsory when the captured piece is promoted.
Furious Fiend move — as in the other large games featuring this piece, players may choose the old TSA Furious Fiend move (Lion + 3-step slide move) or the more current interpretation (Lion + Lion Dog).

That’s it! Note that the old TSA rules included a variant Teaching King move which was nonsensical, as it had the piece moving like a Free King or using a 3-step slide, which completely overlap. The one historical Japanese source I have available clearly indicates a Lion Dog move plus Free King move, and all other sources I can find suggest this move, so I’ve opted not to include the TSA move here.

Sub-Variant: Macadamia Shogi (13×13)

Macadamia Shogi initial position with kanji pieces.

Invented by — you guessed it — HG Muller in 2015, this 13×13 reduction of Maka Dai Dai Shogi retains all the most distinctive pieces in the game and removes most of the weaker ones. The consequence is a quite intense game, where a nerve-wracking opening phase tends to develop into a rather intricate middlegame as the players try to outfox one another with their remaining nimble power-pieces. I’ve enjoyed my time with this game quite a bit, and definitely recommend trying it.

Our implementation of Macadamia Shogi allows players to select the same options as the main game (promotion rule and Furious Fiend move).

Sub-Variant: Hishigata Shogi (19×19)

Hishigata Shogi initial position with kanji pieces.

Hishigata Shogi was invented by Sean Humby in 2005, and attempts to slim down Maka Dai Dai Shogi in a different way. In this game the full-size 19×19 board is retained, but the initial position excludes nearly all the weaker pieces, and the King is placed much closer to the centre of the board and surrounded by his army. The result is an extremely fast-moving game, as the power-pieces swoop dangerously around the board, picking away at the enemy King’s dense pack of protectors until they can find a fatal weakness.

Personally I substantially prefer the original game to this variant; Maka Dai Dai Shogi shines partly because the deadly power-pieces are embedded in vast armies of weak-yet-still-important short-range pieces, balancing out their ridiculous power somewhat thanks to the levelling effect (referred to in my first post on our Ai Ai implementations). Hishigata abandons much of that, and I feel the result is a bit less nuanced. However, I can imagine some players will vehemently disagree with me and will enjoy the frenetic tactical explosion this variant offers, so of course I include it here for everyone to try for themselves!

Upon starting a game of Hishigata Shogi players may choose the promotion rule to use, but there is no choice of Furious Fiend moves as that piece doesn’t appear in this game.

Tai Shogi (25×25)

Tai Shogi initial position with kanji pieces.

Tai Shogi is a truly immense game, and is the second-largest Chess-like game ever created (36×36 Taikyoku Shogi being the largest). On its vast board of 625 squares, players battle it out with dense armies of 177 pieces each, with 93 different piece types present in the initial position. Tai Shogi essentially combines the pieces present in Dai Dai Shogi and Maka Dai Dai Shogi, and adds an additional nine new types of pieces.

Until now I haven’t had the opportunity to play a full game of Tai Shogi, so I’d always seen it as phenomenally impressive, but probably too big to be truly playable. However, since implementing it in Ai Ai I’ve played with it quite a bit, and I have to say I was wrong; Tai Shogi may be huge, but it’s definitely playable! Not only that, the sheer size and scale makes the game feel quite epic, and I’ve enjoyed my time with it so far. For those of you out there who are familiar with Dai Dai Shogi and Maka Dai Dai Shogi, please do give this game a try; the learning curve will be small, since there are only nine new pieces, and you’ll be able to develop some basic strategies based on your experiences with those games.

Tai Shogi has a couple unique properties of note:

No Kings on the board — instead of starting with a King, players in Tai Shogi start with both an Emperor (!) and a Crown Prince on the board, both of which must be captured to win. Since the Emperor can jump instantly to anywhere on the board, that means it effectively serves as a potential extra protector for every friendly piece, adding an additional tactical wrinkle to any battles taking place. Games also tend to run long (2,000 moves is a typical length for a game), since the Emperor is far too powerful to get checkmated in the early stages when few pieces are developed and available to attack it.
Full complement of hook-movers — Tai Shogi players have at their disposal the Hook Mover (double Rook), Capricorn (double Bishop), Tengu (double Bishop + single orthogonal step) and Peacock (double Bishop, but only forward). With six hook-moving pieces on each side of the board, long-distance captures are always a threat, especially later in the game as the board empties out a bit. However, players must use these pieces cautiously — some will demote on capture, and they can’t be spent carelessly as otherwise checkmating the opposing Emperor will become very difficult!

Playing Tai Shogi is quite an experience, and it’s most definitely the most wargame-like of the many Shogi variants I’ve played so far. The starting armies are so huge that the board tends to have multiple local skirmishes happening at the same time, and the advancing Pawn lines backed by swarms of generals and mythical beasts reminds one of the clash of phalanxes of ancient soldiers. The game clearly has scope for incredibly varied strategies, so I’m looking forward to playing more so I can begin to appreciate its subtleties.

Rulesets and Options

Tai Shogi has two main rulesets in use, which substantially change the gameplay:

Japanese Wikipedia rules — These rules essentially combine Dai Dai Shogi and Maka Dai Dai Shogi in their entirety. Most of the pieces from both games are included, and they promote as they do in their parent games, meaning that nearly all pieces in the game promote. Promotions are compulsory upon capturing an enemy piece, as in Dai Dai Shogi.
TSA rules — In the TSA version of the game, promotions are limited to about 1/3 of the pieces in the starting array, similar to Dai Dai Shogi (Pawns don’t promote here, either). Promotions are also compulsory on capture, like Dai Dai Shogi and the Japanese Wikipedia rules.

The additional 60 or so promotions available in (1) make the game feel substantially more hectic than the TSA rules, and since I don’t have the historical sources available to decide on way or the other, I decided to include both rulesets in separate files so that players may choose for themselves. Ruleset (1) is in TaiShogi(JWP).mgl, and ruleset (2) is in TaiShogi(TSA).mgl. Try them both and see what you think!

Note that English Wikipedia has yet another set of promotions, but the entire page appears to be in a state of flux and so I don’t consider those suggested promotions reliable enough to include as a third option. Similarly, the German Chu Shogi Association appears to suggest yet another variant where Crown Princes may promote to Emperors, but I can’t find much support for this idea elsewhere.

Players may also choose between variant piece movements for several pieces:

Great Elephant — this has the same four move options as in Dai Dai Shogi
Furious Fiend — this has the same two variants as in other games including this piece
Fierce Eagle — players may choose between the TSA move given for this piece and the Japanese Wikipedia move
Great Dragon — players may choose between the TSA move and Japanese Wikipedia move

Given the sheer size of this game, I wouldn’t worry too much about which moves you choose; the changes between each option are minor and will have little to no impact on the course of a full game on this massive board, particularly when there are numerous other pieces with substantially more power flying around.

Sub-Variant: Mini Tai Shogi (15×15)

Mini Tai Shogi initial position with kanji pieces.

This work-in-progress variant is my own creation, and is an attempt to shrink down the Tai Shogi experience onto a smaller 15×15 board. The most exciting pieces from Tai Shogi are all present, and players start with Emperors on the board and multiple hook-movers, plus Poisonous Snakes and Old Kites that can promote to hook-moving pieces in the endgame. My test games thus far have lasted anywhere between 400 and 1,000 moves, so still a long haul but substantially shorter than Tai Shogi.

At the start of the game, players may choose variant moves for the Great Dragon, Furious Fiend and Great Elephant. Players can also decide to replace the Emperors with Princes, if they want a less mind-bending endgame; however, I strongly recommend using Emperors to get the full Tai Shogi experience!

As with Tai Shogi, there are two versions of Mini Tai Shogi — one following the promotions set out in Japanese Wikipedia, the other following the TSA rules. The Japanese Wikipedia version has nearly all pieces promoting, while the TSA version has more limited promotions available.

Mini Tai Shogi is definitely a work-in-progress, but so far I’ve found it enjoyable to play. Tai Shogi is such a huge game that reducing it down to 15×15 means eliminating a huge number of pieces from the board; over time I will experiment with different piece choices and arrangements for Mini Tai, and may even produce a second smaller variant with a very different set of pieces drawn from Tai Shogi.

Emperor Endgame Trainer

Maka Dai Dai Shogi and Tai Shogi add a new endgame twist over the other ancient Shogi games — the mighty Emperor, who can jump instantly to any unprotected square on the board. At first this piece is very confusing to deal with, and checkmating it can seem almost impossible. To make the transition to Emperor endgames a bit easier, and to open up a way to have some quick fun with all these crazy Shogi pieces, we added an Emperor Endgame Trainer to Ai Ai that helps you learn how to cope with Emperor endgames.

When you load up the trainer (EmperorEndgameTrainer.mgl), you’ll be given a menu where you may choose five different pieces for Sente to use to try and checkmate Gote, who starts with an Emperor and two Gold Generals. If you have Ai Ai play as the Emperor side, you can experiment with different piece combinations and learn how you can checkmate in these wild new endgames.

Sample starting position with kanji pieces.

Rulesets and Options

Upon loading the trainer, you will be able to choose five pieces for Sente to use, from the entire current list of available Shogi pieces in Ai Ai. However, to keep things applicable to the actual games that use the Emperor, only the pieces available in Maka Dai Dai and Tai Shogi can promote, and they use the promotion-by-capture rule. At the start you may also select whether to have promotion-by-capture as compulsory (like Tai Shogi) or optional (like Maka Dai Dai Shogi).

You may also choose whether one or both sides have a King or an Emperor, if you just would like to gain some experience with some of the Shogi variant pieces in more normal endgame situations. The board size is configurable too.

Note that if you leave piece selections on ‘Random’, you may occasionally get starting positions where the enemy Emperor/King can be captured immediately; for example, selecting a Bishop hook-mover like a Capricorn, Tengu or Peacock as Sente Piece #2 will cause this. If that happens, you can click the Game menu and select Game Parameters to choose different pieces and try again.

Shogi-Inspired Chess Variants

For those die-hard Chess players who miss the classic FIDE pieces and those wonderful FIDE Pawns, don’t fret! I’ve also put together some highly experimental Chess variants that try to capture the large Shogi feel in a distinctly Chess-flavoured package. These games use Chess pieces and popular fairy pieces, but adopt large Shogi conventions like very dense starting setups, promotions for many other pieces besides Pawns, and eschewing castling in favour of starting the Kings in strong fortresses right from the beginning.

All three games are really just intended for fun, so please don’t take them too seriously; having said that, I have playtested them quite a bit and they’re playable and not obviously broken. The starting positions have been tweaked and tuned to avoid any obviously weak squares for either side to target in the opening, the piece mixes have been adjusted following test games, and promotions have been swapped around in each game to try and encourage the use of certain pieces.

Rider Romp (10×10)

This game is sort of a bridge between 10×10 Chess variants like Grand Chess and Opulent Chess and the large Shogi experience. The opening setup is denser than most 10×10 Chess variants, and the pieces are more powerful and many are capable of promotion. The four middle Pawns have been replaced with Stewards, variant Pawns that can move and attack in four directions, which are quite robust defenders; in early testing, a line of ten normal Pawns proved to be somewhat feeble resistance against the onslaught of all these power-pieces.

The name comes from the game’s theme of promoting one’s pieces to stronger forms that include additional ranging moves. Some of the promoted pieces are ‘rider’ pieces, a term originating from fairy Chess which means they extend a basic move by allowing the piece to perform it repeatedly. Nightriders are a classic example — they are Knights that can perform repeated Knight leaps in the same direction in one turn.

Rider Romp starts out fairly tactical, with long-range attacks flying everywhere; just mind the Steward Pawns in the middle four files. Once the board empties a bit promotion really becomes a focus. These games use promotion zones like the large Shogi games, so players will have to try to advance their own pieces to achieve strong promotions, while trying to guard their own huge promotion zone against incursions from enemy pieces with high-impact promoted forms. In my tests a game played out to the bitter end takes about 150-250 moves (using Shogi-style move counting, not Chess style!).

Neutronium Chess (12×12)

Now things get a bit crazier. Neutronium Chess gets its name from the ridiculously dense material that makes up neutron stars, because this game is absolutely packed to the brim with pieces at the start of the game, and there are 33 distinct piece types available for use. The piece lineup includes various strong leaping pieces, some with additional orthogonal or diagonal step options to add flexibility, and powerful sliding pieces as well.

My favourite pieces in this game are the Griffon and Manticore, which are bent slider pieces — the Griffon takes one step as a Bishop then can slide unlimited squares outward as a Rook, while the Manticore takes one step as a Rook and then can slide outward as a Bishop. This gives them some very surprising attack options, but also gives them a fundamental asymmetry; Griffons and Manticores can’t retreat the same way they advanced, so they must be deployed with finesse. This game (and Dai Chess) also contains other bent pieces, including the Crooked Rook and Crooked Bishop that move in zig-zag patterns, and the Ship (invented by Jean-Louis Cazaux here), a vertical-only Griffon.

As with Rider Romp, many pieces promote in Neutronium Chess, so watch out for strong pieces getting even stronger in the endgame. In play this game has an unusual feel, with the phases of the game proceeding in a Shogi-like progression, but the high-powered pieces create complex, long-range tactical shots more reminiscent of Chess. I’m still not sure it’s ‘good’, as such, but I do have a lot of fun playing it. A typical game lasts anywhere from 200-400 moves; the sample game shown above is on the shorter side, finishing at 261 moves.

Dai Chess (15×15)

Dai Chess takes the next logical step and increases the board size to a massive 15×15. This game uses the exact same starting squares for pieces as Dai Shogi, but with all different pieces. All Pawns start the game protected, so there are no immediately obvious weak points to target in the opening. Players start play with 65 pieces each, and there are a total of 46 piece types available for use. Given the larger board size I wanted to try for a more strategic feel in this game, so some of the more powerful pieces from Rider Romp and Neutronium (like the Griffon and Manticore) now only appear via promotion, calming the early stages of the game somewhat. One aspect I’m still working in is the placement of the colourbound pieces, which is troublesome due to the board having odd dimensions rather than even, so keep an eye on that in future revisions.

Dai Chess really amps up the large Shogi feel of this series of variants, not just by using the Dai Shogi position but also by adding more promotions. Nearly every piece promotes, and in keeping with what we expect from Chess, all promotions are an improvement in strength; I’ve avoided any demotions in the style of Dai Dai/Tai Shogi. This game makes use of a lot of leapers, so good tactical vision is necessary to avoid early loss of strong pieces. In the endgame, sliding pieces become dominant as they can promote much more easily, which again is reflective of the large Shogi inspiration.

A typical game of Dai Chess lasts about 400 moves, sometimes substantially more; the sample game above lasted 495 moves. Ai Ai can actually play this game reasonably competently at 15-30s thinking time, but it can end up being a bit greedy in the opening; if you want a greater challenge, trying playing a cautious, positional opening for Ai Ai before turning the AI on. Be careful though — for human players all these weird leaping pieces can make it hard for us to spot good moves, but the AI doesn’t have that problem!

Expanded Chess/Get Bent/Symmetric Sissa

If you’d like to experiment with those interesting bent-slider pieces some more, you can also check out my variant called Get Bent, also added to Ai Ai in this release, which includes a whole mess of them on a 10×10 board; it’s a very fast-paced tactical game. I mainly made it to get familiar with these odd pieces, so it’s just for fun. Pawns promote to extremely powerful Griffon/Manticore compound pieces, so watch out for that!

We have also included Expanded Chess, a nice variant by Daniel Zacharias which has Griffons and Manticores as well, and Symmetric Sissa, a showcase for the multipath Sissa piece, which on each move must take the same number of steps as a Rook and a Bishop (in either order).

None of these three variants have anything to do with Shogi, but since they’re in the new release I felt it was worth highlighting them anyway!

Next Moves

Sorry for the insanely long post, but as you can see, Stephen and I have done a whole lot of work on these games over the last few months. As I mentioned at the beginning of this article, bugs will very likely remain in one or several of these games, but we’ve at least reached a stage where the games all function and we’ve incorporated every rule/piece option that seems plausible.

From here, we hope you Shogi fans will give these games a try, let us know how you find them, and maybe organise a tournament or two. If/when any bugs crop up, please let us know of course!

I’m sure some folks would prefer there were less options to deal with in each game, but honestly I can’t see any other way to go; the alternative would be to decide unilaterally how these games should be played, but the information we have on the historical rules is very fragmented, so I don’t feel qualified to do that. I also don’t want to take sides on the online debates regarding these rules, which have been going for far longer than I’ve known about these games. In any case, my hope is that these options can be trimmed over time as the community tests them out and reaches a consensus on what pieces/rules are most enjoyable. Similarly, as I get my hands on the historical sources I’ll revise things here and there as needed.

After this release we’re taking a little break from Shogi programming, but at some point down the line we do hope to bring in the legendary Taikyoku Shogi as well. That will take a lot of research on my part, given there seem to be major differences in the rules in each of the three main historical sources, but I look forward to learning more about that massive game along the way.

In the meantime, go play some ancient Shogi, and have fun!

Frequently Asked Questions

“How can I choose a Shogi variant to play?”

On the File menu in Ai Ai, click ‘Choose Game’. A new screen will open with a file browser on the left and a preview display on the right. Open the ChessFamily folder on the left, then open the Shogi sub-folder. Within that you will modern 9×9 Shogi, and two sub-folders, one for Historical variants and another for Modern variants. Pick your favourite, double-click it and Ai Ai will load it up!

Alternatively, hit Ctrl+Shift+F (Cmd+Shift+F on Mac) and start typing the name of the game, and you should be able to load it that way.

“How can I play online?”

Instead of running ‘ai ai.jar’, run ‘online.jar’ which is included in your Ai Ai folder. Once it starts up, click the button on the left to create an account, then click the link in the subsequent confirmation email (check your spam folder if you don’t see it). Once your account is confirmed you can login and start playing! Ai Ai supports correspondence-style online play.

“I’m playing Tenjiku Shogi, how do I use igui capture with my Heavenly Tetrarchs?”

Click and drag the Tetrarch on top of the adjacent piece you want to eat, and when you let go of the mouse button that piece will be igui captured.

“I can’t visualise these crazy moves! Can Ai Ai show me where my pieces can go?”

It sure can! There are three main options for this:

On the ‘Settings’ menu, turn on ‘Show available moves’. This will highlight any pieces on your side that have available moves on your turn, and if you click and hold on that piece, Ai Ai will show you what squares it can legally reach.
Also on the ‘Settings’ menu, turn on ‘Highlight moves from position’. When this option is on and you click and hold on one of your pieces, Ai Ai will dim the rest of the board and show you where your piece can move using arrows and will highlight the possible destination squares.
On the ‘Game’ menu, choose ‘Available moves…’ and a window will open up that will show you a visual depiction of every possible move in the current position; you can choose your move by clicking through the different options and clicking OK. Alternatively, simply press Ctrl+M (Cmd+M on Mac) to open that display.

There are many useful display options on the Settings menu, so do make use of them to help you get started with these games.

“How can I change the AI settings?”

On the AI menu, you can choose whether to play an AI vs AI game, human vs human, or human vs AI. You can also use the buttons on the bottom left of the screen to select these options. Click on ‘Set thinking time (s)…’ on the AI menu to determine how long the AI may think about each move.

“How can I see all the piece types present in each game?”

On the Reports menu, click the ‘List Pieces (Chess family only) option. After a few seconds, Ai Ai will generate an HTML table showing all pieces present in the current game you have loaded, including their names, piece graphics, abbreviations in the notation, and Ai Ai’s estimate of their material value.

“Why are the piece abbreviations in the move notation different from the previous convention?”

In Ai Ai we need to define promoted and unpromoted forms of pieces separately. A Lion that appears in the starting position is defined as a separate entity from a Lion that appears when another piece promotes. In most previous implementations, promoted pieces appear in notation as ‘+[piece promoted from]’, so when a Kirin promotes in Chu Shogi, for example, the resulting Lion is notated as ‘+Kr’. However, piece promotions often vary across this set of games, so if we wanted to maintain that we’d need to make lots of duplicate pieces to account for these various promotions.

So instead, we opted to abbreviate a piece that appears after promotion as ‘[promoted piece abbreviation]+’, since this allows for consistency across all the games, and no additional duplication of pieces in the code. So our friend the Lion appears as ‘Ln’ when he starts on the board, and as ‘Ln+’ when he appears by promotion, regardless of what piece he promotes from. In these historical variants this works fine, because promoted pieces never unpromote, so we don’t particularly have to care what piece they promoted from anyway.

This also means that if new large Shogi variants arise in the future, we can easily add in games with new promotions without needing to add duplicate pieces. That in turn makes it possible for enthusiasts to make new variants with different promotions without asking Stephen or I for help writing additional code.

However, the situation changes in games with drops, like Tori Shogi, modern Shogi, or Wa Shogi. In these games, pieces in hand will demote to their previous form, so we *do* need to know what pieces the promoted pieces used to be. So, in these games pieces maintain the standard notation.

“How do I make those cool animated GIFs of my games?”

At the end of your game, click the Game menu and choose the ‘Review…’ option. Once the game review screen opens, click the icon that looks like a strip of film to create an animated GIF.

“How can I tinker with the AI and try to improve it?”

On the Settings menu, choose ‘Select Role…’ and give yourself the ‘Superuser’ role. When you next start Ai Ai, you will have a greatly expanded array of menus and options, many of which will allow you to perform various analyses on games, generate heuristics, test different AI methods and settings, etc. There’s a lot to play with, Ai Ai has many powerful features for game analysis 🙂

“I have a great idea for a modern variant of these games! Can you make it for me?”

If you take a look at the .mgl files that define each game, you can see that creating a new variant is pretty straightforward, so long as it can be constructed out of components (pieces and rules) that Stephen has already implemented. Give that a try first, and if you struggle to get it working, then I can help you to fix it.

“I don’t like the default options you chose for some of these games, and I’m tired of changing them every time. Can I change them permanently?”

Absolutely. Just open up the appropriate .mgl file for that game in a text editor, and find the section at the end called “parameters” — this section defines the options that appear when you load the game. Each option as a default setting, and if you change that to one of the other options listed in the “optionNames” line of that parameter, you will change that default setting permanently.

Just make sure that you save the changed .mgl file with a different name, and keep a backup copy somewhere; otherwise if you copy a new Ai Ai update into the same folder that file will be overwritten by the Ai Ai update.

“Why does the AI struggle with these large Shogi games?”

Ai Ai is a general game-playing framework, and excels at using variants of Monte Carlo Tree Search. Chess-like games don’t suit these kinds of algorithms very well, so Stephen has added a general Chess-playing engine to make them playable. However, because of his engine’s amazing flexibility and generality, each specific Chess or Shogi variant has to be optimised separately to get these best out of the engine, and this takes a lot of time and effort. At this stage we are mainly concerned with getting the games functional, so we haven’t yet engaged in any game-specific optimisation (that will be my job in the months to come).

The main issue though is simply that these games are huge! Every position has a large number of possible moves to search, and the AI is simply not able to search as deeply as it can in smaller games. Extending thinking times does help, but even getting 4-5 moves deep requires far, far longer than in smaller games. Eventually I hope to experiment with using other AI methods for these games, but this will take a lot of time.

So, for now at least, please be patient and give the AI as much time to think as you can stand 🙂

“Hey Eric, why didn’t you include [my preferred rule]? It’s clearly superior because….”

I completely understand that some modern players would prefer I chose one set of definitive rules, but the problem here is there’s no consensus on what those definitive rules should actually be, and some of these arguments have been going on far longer than I’ve been involved in the Shogi variant world. That being the case, I’ve decided to opt for a preservation approach, where any rules proposals that are plausible given the historical information we have on these games are kept alive in these implementations and given as an option.

My hope is that over time, the Shogi community will try these various options and decide on a ruleset for each game that we can consider the modern standard. At that point, I would be happy to revise these implementations to have one ‘standard’ version for each game, and preserve old options in a secondary, customisable implementation, for posterity.

“Hey Eric, why did you include stuff nobody plays anymore, like Hodges’ moves for the Lion Hawk and Free Eagle?”

If a move or rule has been played extensively and is plausible in some way, then I’ve tried to include it, regardless of its popularity. I initially wasn’t going to include Hodges’ moves, given the modern Tenjiku community seems to have rejected them, but then I read this old correspondence of his on that very issue:

“I well remember my and John Fairbairn’s discussions with our good friend Maruo all those years ago when we were discussing the more exotic variants in his house. He was absolutely adamant that [the Lion Hawk] does NOT have Lion Power. There are several points to make. Firstly, his interpretation is in our mind in no doubt whatsoever. Secondly, translated text … says words to the effect “…moves like a Lion…”, now this is simply a short way of describing a two-step mover in all directions. Lion power is something quite different.”

He went on to explain why appeals to logic (“why would the Lion promote to a weaker piece?”) and symmetry don’t work, because plenty of ancient Shogi games include demotion and substantial amounts of asymmetry.

I found this argument reasonably compelling, and given that George was a scholar with connections to Shogi history researchers in Japan and had direct access to the historical sources, we can reasonably assume his opinions on these matters were well informed. Therefore, I had to consider those moves plausible, and decided to include them as an option.

“Hey Eric, why didn’t you include my Shogi variant?”

We might do that later, but for now the focus is on the historical variants. Modern variants, particularly modern variants that are already playable elsewhere, are of much lower priority because they don’t need our help to be preserved and made playable. Also, speaking for myself I prefer to work on variants I have personal experience with, and I am deeply obsessed with large Shogi and much less so with smaller modern variants 🙂

Tagged Ai Ai, Cashew Shogi, Dai Chess, Dai Dai Shogi, Expanded Chess, Get Bent, Macadamia Shogi, Maka Dai Dai Shogi, Makyou Shogi, Mini Tai Shogi, Neutronium Chess, Nutty Shogi, Rider Romp, Shogi, Shogi Variants, Symmetric Sissa, Tai Shogi, Tenjiku Shogi

Apr 22 2021

5 Comments

Games, Shogi

Shogi variants: translation notes (I)

One of the many challenges of working on the large Shogi variants is the language barrier. Not only are the historical documents explaining these games in Japanese, they are in medieval Japanese, and medieval Japanese is written very differently from the modern form of the language. For a start, many texts were written using only Chinese characters (kanji), and without the helpful hiragana and katakana syllabaries found in the modern language. On top of that, the usage of kanji has evolved over time, and as with any other language, over the centuries the style of writing has evolved too.

Combine these factors with the generally terse writing style of these old documents, and a natural tendency for Shogi fans to feel quite passionate about their particular interpretations, and we end up with fairly frequent disputes over some rules and piece abilities in these games. Just to be clear about this, for aspiring Shogi researchers: DO NOT use Google Translate on these old documents! Google Translate understands modern Japanese (sort of), but has very little idea of what is being said in these old texts. Even native Japanese speakers have great difficulty interpreting these documents.

Below is an example of the challenges we faced in implementing Dai Dai Shogi, a 17×17 Shogi variant with a large array of 96 pieces of 64 different types for each player. Somewhat remarkably, most of these pieces have largely agreed-upon powers, but there are two in particular with some disputed abilities: the Furious Fiend, and the Great Elephant. These are my notes on these pieces that I put together for Stephen, cleaned up and with a bit more explanation. I share them here as I thought it might be interesting for some of you to see the work that goes on behind the scenes as we try to bring these games to life.

Ultimately we opted to preserve the versions of these pieces that have some historical justification, and allow the player to choose the one they prefer. As you will see, the pieces change quite a bit depending on which source you use!

——-

: The Lion’s move

: The Lion Dog, which only appears in Shogi variants larger than Tenjiku Shogi

Furious Fiend (promoted Lion)

The Furious Fiend is the promoted form of the Lion in Dai Dai Shogi and Maka Dai Dai Shogi. Many of you will remember the Lion from Chu Shogi, where this unique and powerful piece dominates the board; for those new to these games, here’s a brief summary of it’s prodigious powers:

The Lion may move twice in one turn like a King — one step to any adjacent square
This double-movement power allows numerous unusual abilities:
- The Lion may step to an adjacent square, then back to its starting square — effectively passing its turn
- It may capture a piece on an adjacent square, then move back to its starting square, appearing to capture an adjacent piece without moving — this is known as igui, ‘stationary eating’
- It may capture two pieces in one turn
The Lion may also jump to any square within the 5×5 area around its starting point (but this then is its entire move for the turn)

In the diagrams you’ll see in this article (and in Ai Ai when using the diagrammatic piece sets), orange squares represent places the piece may step to; the stars represent squares a piece may jump to; an exclamation point indicates a square where capturing without moving is possible (igui); and a red arrow indicates the piece may move unlimited squares in that direction.

Having all of these movement possibilities gives the Lion immense power and flexibility, but in the larger games, the Lion is far from the strongest piece! One of its beefier cousins is the Lion Dog, which we also need to know about in order to understand the Furious Fiend and the Great Elephant:

The Lion Dog has a three-step ‘Lion-Power’ move, but restricted to one direction only. Once the Lion Dog chooses one of the eight possible directions for its move, all of its subsequent moves must take place along that same direction of movement, and the Lion Dog may not move backward past its starting square.
With its three-step Lion move, the Lion Dog may:
- Jump directly to the third square (and capture any enemy there)
- Jump to the second square, then proceed to the third, or backward to the first, potentially capturing two pieces
- Step outward along that direction up to three times, capturing up to three pieces
- At any point it can stop, the Lion Dog is not required to use all three Lion-power moves.

So the Lion Dog extends the Lion’s power by allowing potential triple-captures, but its flexibility is reduced somewhat as those captures must all take place along the same line.

In Dai Dai Shogi and Maka Dai Dai Shogi, there are compound pieces that combine Lion and Lion-Dog moves with the moves of other pieces. One of those is the Furious Fiend, the promoted form of the Lion itself.

: Furious Fiend with a Lion move + 3-step slide in the eight orthogonal/diagonal directions

: Furious Fiend with a Lion move and a Lion Dog move

There are two main versions of this piece:

Lion + an option to slide three steps in any of the eight directions
Lion + Lion Dog

The evolving consensus at this point is that (2) is the correct move. (1) is likely a relic of a misunderstanding that pervaded the English literature on these games for a long time, where the Lion Dog was thought to have a three-step move in any direction without Lion power, but that’s considered a misapprehension now. For those of you who may have physical Dai Dai Shogi sets from The Shogi Association, the manuals included in those games include this version of the Lion Dog; for that reason, this version is sometimes referred to as being part of the ‘TSA rules’.

So, when that non-Lion-powered move was prevalent, and the old texts said Furious Fiend moved as ‘Lion + Lion Dog’, when you combine these moves you end up with (1). But with our corrected understanding of the Lion Dog, we get (2). In our Ai Ai implementation, we have allowed players to choose which version of the Furious Fiend to use in Dai Dai Shogi and Maka Dai Dai Shogi, since both have been used in modern play.

——-

Great Elephant

Some Shogi scholars suspect that Maka Dai Dai Shogi had some fans back in the day — it’s the most consistently-described of the very large games in the historic sources, with few discrepancies despite the texts being written years apart by different people. Players also developed a chant in Chinese that they’d use to remember the initial setup, so that’s an indication it was being played some amount. This can be helpful when questions arise about other games, because if that same piece appears in Maka Dai Dai we may be able to get a more consistent picture of how that piece should work.

The Great Elephant, however, does not appear in Maka Dai Dai Shogi and instead only shows up in Dai Dai Shogi (and the 25×25 Tai Shogi), where it is the promoted form of the Lion Dog; in Maka Dai Dai Shogi, the Lion Dog is one of the strong pieces that demotes to Gold General. The Great Elephant is described in very different ways in the available historical sources that explain the rules of Dai Dai Shogi. These are the main options, according to the sources I’ve seen before:

The piece doesn’t exist at all (!) [two sources don’t have the Lion Dog promote to anything, so this piece doesn’t exist in Dai Dai Shogi in those documents]
The piece moves as claimed in a note on Japanese Wikipedia: Steps 1-2 squares diagonally forward, or unlimited slide in all other directions *and* it may jump over up to 3 pieces, friend or foe, and continue its slide on the other side
The piece moves as described in (2), except that it *cannot* jump over pieces
The piece moves as in Taikyoku Shogi: steps 1-3 squares diagonally forward, or unlimited slide in all other directions and it may jump over up to 3 pieces and continue sliding on the other side of them.
The piece may step 1-5 squares sideways or diagonally backward, or 1-3 squares in the other directions [this move is widely discredited now, given that it’s based on the old TSA interpretation of the Lion Dog].

However, in an effort to further develop our understanding of this disputed piece, I obtained a copy of the ancient document Shogi Rokushu no Zushiki from the Japanese National Diet Library, and have gone through every scrap of info on Dai Dai Shogi in there. This is document includes the Great Elephant as the promotion for the Lion Dog. After deciphering the notation based on the text descriptions of various pieces’ movements, and examining the diagram of the Great Elephant’s move:

GE_SSZ_diagram

I believe this diagram from the text indicates the following move:

Lion-Dog-style 3-step Lion Power in the four orthogonal directions and diagonally backward
Or it may slide unlimited squares in the four orthogonal directions or diagonally backward
Or it may step 1-2 squares diagonally forward.

The key is the three slashes over the longer lines. The text very clearly states that the long lines indicate unlimited sliding moves in those directions. There is only one other piece that is given a text description that has the three slashes overlapping the longer lines, and that is the Teaching King in Maka Dai Dai Shogi’s section in the text, and that text says the Teaching King functions as Lion Dog + Free King. So, we can infer from this that those three slashes indicate Lion Dog moves in those directions:

: Teaching King move diagram

: Text: “Deva promotes to Teaching King, which moves as the two pieces the Lion Dog and the Free King…”

Here we have the source of some confusion. The Lion Dog’s move is described in this text using the word ‘odoru’, which means ‘dance’, and depending who you ask, ‘odoru’ in this context either means a Lion-Power move, or a leaping move where you can jump over some number of other pieces.

So that leaves us with two plausible options, depending on how we interpret ‘odoru’:

if ‘odoru’ means ‘leap over stuff’: that’s the Japanese Wikipedia move, (2) above
if ‘odoru’ means ‘Lion Power move’: that’s my interpretation above

However, I consider (2) to be the more plausible interpretation, and easier to place among the rest of the Dai Dai Shogi army. That move would make the Great Elephant a promotion above the Lion Dog, given the added mobility, but reducing the Lion-Power directions to six makes it less powerful than the Teaching King/Buddhist Spirit. This makes some intuitive sense, as the Teaching King and Buddhist Spirit are the strongest Lion-Power pieces in Maka Dai Dai Shogi, and typically the larger games introduce additional, more powerful pieces over their smaller cousins. Meanwhile, (1) would require a new mechanic that only appears for this single piece, and does not otherwise appear in Dai Dai Shogi at all, so it does not seem likely. However, Dai Dai Shogi does introduce two hook-moving pieces that can perform double Bishop or Rook moves, so it’s perhaps not impossible that the creators would introduce another form of movement as well.

I should mention that Shogi Rokushu no Zushiki is known for having a lot of differences in how pieces move in all the games it covers, and that includes Dai Dai Shogi. However, the power-pieces in each game do seem to agree with other sources from that period. The beginning of the text opens with the author complaining about transcription errors and incorrect piece names in other documents about Shogi, so he is presenting himself as correcting the historical record, but today we consider many of his claims to be questionable. In any case, I feel it’s worthwhile to try to understand the Great Elephant move presented in this text and see whether it fits in the game as we know it today, and give players a chance to try it for themselves*.

The English/Japanese Wikipedia seems to have simply removed the Lion Dog moves from the Shogi Rokushu no Zushiki move and given the Great Elephant the six ranging moves and diagonally-forward stepping moves only. This is nice and simple but I don’t think this is a correct interpretation of this particular text. However, this move has been widely used until now, and certainly is a playable variation with some historical justification.

The Final Move Choices

: (1) Great Elephant move from Shogi Rokushu no Zushiki (my translation)

: (2) Great Elephant move from English/JP Wikipedia

: (3) Great Elephant move from the notes on Japanese Wikipedia

: (4) Great Elephant move in Taikyoku Shogi

We are left with three main usable interpretations of the Great Elephant in Dai Dai Shogi/Tai Shogi, after we discount the one related to the old TSA Lion Dog move, plus one variant for use in Taikyoku Shogi only:

1. Steps 1-2 squares diagonally forward, or slides unlimited squares in the four orthogonal directions + diagonally backward, or 3-step Lion Power move in those same six directions [my translation of SRZ]
2. Steps 1-2 squares diagonally forward, or slides unlimited squares in the four orthogonal directions + diagonally backward [English/JP Wikipedia]
3. Steps 1-2 squares diagonally forward, or unlimited slide in all other directions *and* it may jump over up to 3 pieces, friend or foe, and continue its slide on the other side [JP Wikipedia move in the notes]
4. In Taikyoku Shogi it moves as (2), except it may move 1-3 squares diagonally forward instead of 1-2. Hopping-ranging moves are commonplace in Taikyoku Shogi, so that move is uncontroversial in that game.

Given the lack of consensus, we opted to implement all three possible moves for Dai Dai Shogi and Tai Shogi (1, 2 and 3 above), and allow the player to choose. So at the start of the game, you may choose your preferred move of the Furious Fiend and the Great Elephant before starting play. The Taikyoku Shogi move will be relevant once we get to that game!

We also include an alternative implementation of Dai Dai Shogi which does not include the Great Elephant, since two historical sources indicate that the Lion Dog does not promote at all.

As for the diagrams, for the range-jumping move in (2) and (4), we use a numbered circle to indicate how many pieces may be jumped over in one move. In Taikyoku Shogi this number varies between pieces, so we will continue to use this notation when we start working on that game and more range-jumping pieces appear.

Conclusions

So, after all that work, we ended up with a robust implementation of Dai Dai Shogi which we think covers all the main bases for the Great Elephant: the long-distance sliding piece espoused by English Wikipedia; the long-distance jumper suggested in the notes on Japanese Wikipedia; and the powerful Lion Dog compound suggested by the text of Shogi Rokushu no Zushiki. Players may also choose between either version of the Furious Fiend. Finally, we also allow players to ditch the Great Elephant entirely.

Having experimented with these variations myself, here are my impressions (note that I’m excluding the Taikyoku Shogi version, which will feel very different in that game, given the enormous 36×36 board and the presence of other range-jumping pieces):

Great Elephant move from English/JP Wikipedia

This piece is highly mobile, which makes it very useful in the endgame, where mobility becomes very powerful as the board starts to empty of other pieces. However, the lack of Lion Power does mean that players have to consider their strategic aims when deciding whether to promote this piece. In a congested middlegame position, for example, one may want to avoid promoting the Lion Dog early so that the Lion Dog still presents a powerful capturing threat. In a late-game situation where enemy defences have thinned out, then making a capture and promoting the Lion Dog may be well worth it, as the new-found mobility will come in handy.

Great Elephant move from the notes on Japanese Wikipedia

This piece is amazingly fun to use! Given the congested, high-density setup of Dai Dai Shogi, having the ability to leap any distance over three pieces is hugely helpful. Promoting this piece loses the Lion Dog’s multi-capture abilities, certainly, but in exchange you gain incredible flexibility, plus the option of threatening the enemy King even over a dense wall of protective pieces. I’d imagine that few players would hesitate to promote their Lion Dogs if this promotion is available; the piece just gives you so many new options when on the attack, and as the only long-range jumper on the board, it’s very hard for your opponent to chase it down.

I have had so much fun with this beast that I’m getting very excited to work on Taikyoku Shogi further down the line, where lots of these range-jumping pieces will appear.

Great Elephant move from Shogi Rokushu no Zushiki (my translation)

This piece ends up feeling surprisingly well-balanced, in my opinion, with the rest of the power-pieces available in Dai Dai Shogi. When promoting to this from Lion Dog, one loses the option to perform multiple captures in all eight directions, but in return gains significant mobility. However, that mobility is less useful on the attack, as the forward diagonal moves are only two-square steps.

The result is a piece that feels like an upgrade from the Lion Dog, but nevertheless requires finesse to use effectively. The Great Elephant also proves to be a powerful and mobile defender, able to move backward into a defending posture quickly and mop up several opposing attackers at once. To me it’s an interesting piece to use, and it feels like a viable addition to the game.

In my testing, the presence of the more powerful Elephants, either the SRZ version above or the range-jumping variant from Japanese Wikipedia, has not significantly influenced the length of the typical game. Dai Dai Shogi is a big game with lots of pieces on the board, and even the most powerful pieces have to bide their time until their powers can flourish; otherwise they have to run away from constant threats of capture from the hordes of weaker pieces**. So the stronger Elephants have a big influence in the endgame, but overall don’t feel overly unbalancing. In my opinion, though, the SRZ version is the one I would advocate if you want a stronger piece than the English Wikipedia version; the range-jumping Elephant feels a bit out of place with its highly unusual movement abilities, whereas the SRZ variant feels more at home amongst the other Lion-Power pieces on the board.

: Furious Fiend with a Lion move + 3-step slide in the eight orthogonal/diagonal directions

: Furious Fiend with a Lion move and a Lion Dog move

As for our furious friend the Furious Fiend, both versions are a straight upgrade from the Lion, and I don’t think either one makes a significant difference in the overall shape of the game. The Lion + Lion Dog version can make additional captures in some circumstances, but against a good opponent this is unlikely to come into play very often — a good player will never allow three of their strongest pieces to be in range of a Furious Fiend at the same time!

In this case the choice comes down more to personal preference. I like the more powerful Lion + Lion Dog variant, as it feels like a more significant upgrade over the Lion, which adds incentive to move the Lion into battle in the first place. I also feel it’s more likely to be the intended move, given that the old documents position it as Lion + Lion Dog and we now understand the Lion Dog move to have multi-capture abilities.

Next Moves

So, at this point we are close to finishing our time with Dai Dai and Maka Dai Dai Shogi, so you can look forward to a more detailed look at those games on this blog in the near future. In the meantime we are getting started on Tenjiku Shogi, which is an exotic and exciting game with a lot of disputed rules and pieces to sort through, so I may do another ‘translator’s notes’ article on that game once we complete it.

I hope some of you out there may give these games a try in Ai Ai when you have a chance; they really are unique games in the history of the Chess family, and deserve your attention! Though these games are many centuries old, they have unique ideas and pieces that still stand out today, even amongst the thousands of Chess variants that have been constructed since. Give them a try, and you may find you enjoy the sheer immensity and creativity of these fascinating games.

UPDATE: I’ve been really pleased to discover that the Dai Dai Shogi page on Wikipedia has been updated with a diagram of the move I suggested from my interpretation of Shogi Rokushu no Zushiki:

wp_great_elephant_update

I’d like to give a hearty thank you to HG Muller and Wikipedia user Double Sharp for taking note of my arguments here and presenting this move as one possible interpretation on the Wiki page, I very much appreciate that my work on this was recognised. I also agree with both of them that this piece is seriously confusing, and we’ll probably never be able to definitively decide whether it should even be in the game at all!

* I suspect some readers may be wondering: why did I pick out this one piece and elevate it to the status of a plausible move, when the rest of the source text is viewed with skepticism (and justifiably so)? My answer is that the Great Elephant in particular is a mysterious piece, sometimes existing and sometimes not, and when it does exist, every source seems to have different opinions about its moves. While Shogi Rokushu no Zushiki has a lot of move descriptions that don’t match other sources, it *is* a source that actually contains the Great Elephant, and so I decided to investigate it. I found that the move looked more complex than I’d expected, and yet the positioning of the stepping and sliding moves exactly matched the diagram provided on Wikipedia. That led me to think that it would be worth looking more deeply at this move, and what I found seemed potentially interesting to try within the current agreed-upon Dai Dai Shogi ruleset, even when taken out of the context of the SRZ account of Dai Dai Shogi.

I left the other moves from SRZ aside, as the other pieces in Dai Dai Shogi have a consensus regarding their moves and abilities, so in that context I don’t see a need to replace them with moves from a single divergent source. That’s not to say some of them aren’t interesting; SRZ gives the Golden Bird almost the reverse of the Great Elephant move, with Lion Dog moves on the front diagonals and limited 3-step retreating moves (without Lion Power). But that piece exists in Maka Dai Dai Shogi and the moves appear to be consistent across the other sources, so I can’t see a justification for replacing it with the SRZ move.

In short, I wanted to know more about the Great Elephant, and found the move in SRZ to be both plausible and interesting, so I wanted to give players a chance to try it!

**This phenomenon of stronger pieces sometimes being a liability is seen in all Chess-like games and was dubbed the levelling effect by great Chess variant explorer Ralph Betza. Put simply, because different pieces have very different levels of power and influence on the board, a threat against our weaker piece from the opponent’s stronger piece is often no threat at all, because if those pieces are traded off we still end up ahead in material strength on the board. However, a threat against a stronger piece from a weaker piece must be defused immediately, because if we allow that trade of material we hand the opponent a strength advantage. This is why the advice in the Chess opening is never to bring the Queen out too early: your opponent can attack it and chase it away with their weaker pieces, as you’re forced to retreat it to avoid a bad exchange, leaving you under pressure and lacking initiative.

The levelling effect is also evident in large Shogi variants, where the board tends to be thick with dozens of pieces, many of them weak. The powerful pieces therefore have to be deployed cautiously, given the sheer number of possible threats from the opponent’s huge army.

Some large Shogi pieces are not quite so vulnerable to this however, simply because they are ridiculously powerful. Tenjiku Shogi’s Fire Demon is a good example — the Fire Demon instantly destroys all adjacent enemy pieces, even on the opponent’s turn, so threats against it have to be made at a distance. Similarly, the various Lion-Power pieces cannot be chased away by single-step-moving pieces, because those pieces have to be adjacent to threaten to capture, and the Lion-Power piece can simply take them at will with an igui capture.

Note that the SRZ Great Elephant does have vulnerable areas along the front diagonals, where it cannot make a Lion Dog move! This reduces its attacking presence, as there are several weak pieces with short movement ranges (2-3 squares) that could make credible threats along those diagonals, forcing the Great Elephant to retreat or be captured.

Tagged Dai Dai Shogi, Furious Fiend, Great Elephant, Maka Dai Dai Shogi, Shogi, Shogi Variants, Tai Shogi, Translation Notes

Sep 13 2020

1 Comment

Games, Shogi

Dai Shogi, Part II: A Sample Game

What with one thing and another, I haven’t had the time or energy to write gaming-related posts for a while, and in particular annotating very long games of large Shogi variants just seemed a bit too much to handle. However, lately I’m in desperate need of distractions to keep positive and motivated, so it’s a good time to get back to writing. For my first post in ages I decided to jump right into the deep end — so here we have an annotated Dai Shogi game! If you’re new to Dai Shogi, please check out my detailed introductory post on the game here.

You may well ask, quite reasonably, why am I doing the Dai Shogi game before the Chu Shogi one I’d promised to do? Wouldn’t the Chu Shogi game be about half as long, and have more resources available for you to draw on when analysing it? Yes to both of those questions, but I feel a bit more urgency to promote Dai Shogi than Chu Shogi; Chu Shogi is already pretty well-regarded among those who’ve heard of it, and is frequently referred to as one of the best Chess-type games ever created. Dai Shogi, on the other hand, is often thought to be Chu’s boring, slower sibling, and this idea seems to have been spread largely by people who’ve never actually played the game.

I feel this is very unjust, as Dai Shogi is a beautiful game that in my view deserves just as much attention as its slightly smaller brother, and has unique charms that set it apart from Chu and from the other large-board Shogi variants. So, I hope that by providing some in-depth discussion of the game, perhaps a few people out there might choose to forget the nay-sayers and give the game a shot.

In fact, as far as I can tell, this may well be the only annotated Dai Shogi game in English on the Internet right now. The game I’ve chosen was played on Richard’s PBEM Server and is listed, somewhat confusingly, as Chu Shogi Game 420. This is due to the fact that Dai Shogi is a sub-option of the Chu Shogi section on the PBEM Server. Our combatants are Sean Humby (shumby) playing Black, and tkr101010 playing White. We will follow Shogi convention, and have Black at the bottom of each diagram and playing upward, and White at the top of the board playing downward. I provide a diagram every ten moves, with some extra ones at the very end of the game.

This game is actually somewhat shorter than most of the Dai Shogi games I’ve played, ending at 441 moves, but throughout there’s no shortage of action, clever manoeuvring, and sharp tactical exchanges. I think this game offers a nice peek at what Dai Shogi has to offer, and I hope it will inspire some of you out there to give it a try.

Before we get started, I’ve placed my Dai Shogi move reference guides here again, in case you’d benefit from a reminder of how the pieces move and promote:

Dai Shogi reference sheet (1-kanji pieces)

Dai Shogi reference sheet (2-kanji pieces)

You can also find PDF versions here:

dai-shogi-reference (1-kanji)

dai-shogi-reference (2-kanji)

Now that’s out of the way, let’s get started! First, let’s remind ourselves of the starting position of Dai Shogi:

The Dai Shogi starting position is slightly more convenient than Chu Shogi’s, in the sense that the Kings both start already ensconced in a pretty reasonable castle. They are surrounded by strong defensive pieces from the beginning — a Drunk Elephant to the front, a Blind Tiger to the front-left and front-right, and Golds on both flanks. As a result of this both players focus entirely on developing their pieces in the opening, as King safety is already sorted out.

1 P-7j 2 P-8f 3 P-9j 4 DK9d-8e 5 P-3j 6 DK-7f 7 P-13j 8 DK7d-8e 9 DH-9i 10 DK-9f

Right from the start both players adopt a fairly aggressive posture. Black opens lines for his Dragon Kings, Dragon Horses and Flying Dragons with four Pawn moves, leaving a lone Dragon Horse perched atop the Pawn on 9j. White takes things a step further, opting to move only the central Pawn and bring both his Dragon Kings straight to the front of his formation. Both players appear ready to fight!

11 DH-10i 12 DK-7g 13 DHx14e+ 14 FD-12b 15 +DH-10i 16 R-14d 17 FD-12j 18 R-14g 19 DH-7i 20 P-6f

Black responds to White’s provocation by pulling off a sneaky manoeuvre with his Dragon Horse — he takes the Pawn on 14e, where neither the Rook nor the Flying Dragon can retaliate. White moves the Flying Dragon out of harm’s way, leaving Black with a gain of initiative and his Dragon Horse now promoted to a Horned Falcon. White brings out his Rook from the 15th file and sets it up in defence of his advanced Dragon King. Somewhat ominously, White then advances the Pawn on 6e, suggesting a path of egress for the Lion on 8c.

In this opening we can get a taste for the sheer variety that is possible in the early stages of a Dai Shogi game. While the board is large and progress can seem slow, both players also have a plethora of very powerful pieces lurking just behind that first layer of Pawns. So a Dai Shogi opening can be slow and stately, or aggressive and tactical, or often a mix of both.

21 +DH-10j 22 DK-2g 23 FD-4j 24 P-3f 25 P-8j 26 FD-4f 27 Ln-8k 28 VO-14e 29 I-12n 30 CS-14c

Here we start to see both players beginning to shore up their flanks. In Dai Shogi the central files around the King are thick with the strongest pieces in the game, so attacking in the middle is a difficult proposition. Instead, advancing along the flanks is more typical, as players develop pieces along the sides of the board, eventually aiming to draw out those powerful central pieces and begin eroding the opponent’s defences.

White shows their intent to attack along the right side, bringing their Dragon King over to the 2-file from the centre and advancing the Flying Dragon behind it. At the same time they bring up their Violent Ox on the left to defend the Rook on his forward outpost. Black also starts progressing on both flanks, bringing forward their Flying Dragon on the right and the Iron General on the left. They also bring the Lion forward; clearly Black noticed White’s advancement of the 6-Pawn and doesn’t want to be caught unawares by White’s Lion.

31 I-4n 32 I-13b 33 P-6j 34 I-13c 35 I-13m 36 I-14d 37 I-14l 38 DH-9d 39 P-3i 40 DHx2k+

Both players now take a moment to make a number of Iron General moves on the left side. This may seem odd, but in Dai Shogi, as in Chu Shogi, we should never forget about advancing the weaker pieces to the front lines. Pawns can only capture forward, and therefore can’t protect one another, so they rely on the protection of the Generals and other short-range pieces. Without protection your Pawn line will be weak, allowing the opponent’s mobile long-range pieces to gobble them up and open up your camp to attack.

White then wastes no time pressing their attack on the right, bringing forward a Dragon King which then pierces into Black’s right flank, taking out the pawn on 2k. The now-promoted Dragon King is backed up by the Dragon King on 2g, giving White a strong attack down that file.

41 VOx2k 42 DKx2k+ 43 N-3m 44 +DK-6g 45 SM-2l 46 P-2f 47 N-2k 48 VO-2e 49 AB-3m 50 FD-10d

Unsurprisingly, Black elects to take the attacking Horned Falcon on 2k, after which White takes back with the Dragon King, which then promotes to Soaring Eagle. Black has no pieces around that can take the Eagle, and White cannot take the Rook or will be taken by the Reverse Chariot, so White happily retreats the Eagle to 6g. Black then shores up his defences around the 2-file, bringing in the Side Mover and Angry Boar. White takes a moment to defend the Pawn on 11e with his Flying Dragon; that Pawn could otherwise be taken by the Dragon Horse on 7i, allowing Black another promotion.

51 AB-3l 52 Ln-6e 53 Ln-6k 54 Ln-4g 55 DH-6i 56 Ln-4i 57 Lnx4i 58 +DKx4i 59 DHx9f 60 Px9f

Here we have a somewhat surprising turn of events. White finally advances their Lion, only for Black to do the same, and ultimately we end up with an exchange of Lions on 4i. Unlike Chu Shogi, in Dai Shogi the Lion has no special protection against being traded off the board. That means that on occasion players will trade them off to simplify the game somewhat.

For Chu Shogi players this can be a bit disappointing, but one of the reasons I chose this game to analyse is that I wanted to show that even without the mighty Lions running amok, Dai Shogi has a lot to offer. The game still has sharp tactical moments and ample strategic manoeuvring, so I feel it’s worth looking at a game like this to demonstrate that the absence of a Lion needn’t make the game boring.

Following the exchange of Lions, Black’s Dragon Horse is vulnerable to capture by the Soaring Eagle on 4i, so Black elects to take White’s Dragon King on 9f. This is a slightly advantageous exchange for Black, as the Dragon King is generally considered slightly more powerful than the Dragon Horse.

After these exchanges, White has an advanced Soaring Eagle perched on 4i, though Black has a good defensive line along the 4th rank. Meanwhile, Black has a slight advantage in the centre due to the protected Horned Falcon on 10j.

61 AB-3k 62 R-10g 63 +DHx6f 64 FD-5g 65 +DH-9i 66 +DK-4h 67 FL-5m 68 +DKx!3i 69 FL-6l 70 +DK-2j

White brings cross their Rook to attack the dangerous-looking Horned Falcon, but Black simply uses this opportunity to grab an unprotected Pawn on 6f before retreating back to a safe square. White then gives us a timely reminder that an absence of Lions doesn’t mean an absence of Lion Power, and uses the Soaring Eagle’s forward-diagonal Lion Power to take a Pawn without moving!

Black now has their Angry Boar standing in defence of the Knight on 2k, and their Ferocious Leopard is shuffling over to join the front line. White’s Soaring Eagle continues to be a threat, as Black has nothing in place that can drive it off yet. The Eagle could potentially double-capture on 3k and 4l, leaving the 3-file very weak, but the possible recapture of the Eagle by the Side Mover makes that a difficult trade to justify. Even so, just the presence of such a dangerous piece on Black’s periphery demands a response.

71 +DH-1i 72 FD-4h 73 +DHx2j 74 FDx2j 75 FD-3i 76 FDx3k+ 77 I-3m 78 +FDx4l 79 Ix4l 80 SM-2d

Black wastes no time here and swings his Horned Falcon all the way across to 1i, where it threatens the Soaring Eagle and is protected by the Knight on 2k. White brings their Flying Dragon forward to protect the Eagle, and Black immediately makes the exchange. Black then offers an exchange of Flying Dragons, but White elects to take the Cat Sword in exchange, leaving Black with a Flying Dragon perched on 3i.

Black made a pretty significant decision here to exchange the Horned Falcon for the Soaring Eagle, but I believe it was a sensible call. The Eagle was in a prime attacking position, while Black’s Falcon was sitting rather idle in comparison. The Eagle could have done significant damage to Black’s right flank using Lion Power, which would have forced Black to spend significant time plugging those newfound holes on that side. Instead, better to make some exchanges and calm things down on the right flank before White does any more damage to Black’s position.

81 C-4n 82 VM-3d 83 C-3m 84 P-3g 85 ST-4n 86 P-3h 87 FD-4j 88 P-2g 89 EW-5m 90 VO-2f

With the immediate threats defused, Black moves to shore up his defensive lines on the right, bringing the Copper General, Stone General, and Evil Wolf into play, while also retreating the Flying Dragon to a protected position on 4j. White continues to press on the right, advancing more Pawns and the Violent Ox. Black’s defensive moves here are very prudent; White clearly wanted to break through on the right, and hasn’t given up on that plan just yet.

91 S-5n 92 P-2h 93 C-3l 94 N-3c 95 R-1m 96 CS-2c 97 C-3k 98 N-2e 99 C-3j 100 B-7f

As expected, White keeps up the pressure on the right flank, bringing forward the Knight and Cat Sword. Black responds by advancing the Copper General all the way to 3j and shifts the Silver General off the back line. White then ups the pressure even more, using the Bishop to take aim at the vulnerable Copper.

At the moment White appears to have the advantage — they are exerting pressure along the right flank, and have a slight material edge. Black will need to keep their front lines solid along the right to withstand the assault.

101 I-3k 102 P-4f 103 P-7i 104 B-5h 105 DK9l-8m 106 N-1g 107 Bx10g 108 FK-10f 109 B-7j 110 B-2e

Black decides to tackle his problems by going on the offensive. He opens a line for the Bishop by moving the 7-Pawn, and subsequently takes White’s Rook on 10g, which addresses the material-balance issue. White drives the Bishop away with his Free King, but Black can simply pull back and force White’s Bishop to retreat as well.

At this point in the game White has done some damage with these early attacks, but Black remains solid and has constructed a pretty sturdy front line. Many of the Pawns are backed up by other pieces, and Black has a slight edge in development, having brought more of his back-line Generals forward. These early decisions have significant ramifications in the late game, where slow-moving pieces closer to the front may promote and generate threats at a point where the more powerful pieces have been exchanged off the board.

111 GB-5i 112 P-9g 113 P-5j 114 EW-9d 115 Ph-5k 116 DH-7d 117 I-13k 118 VO-14g 119 VO-14l 120 I-14e

White seems aware that his position has some weaknesses, and here stops pushing along the right side to focus more on development on the left flank and in the centre. Bringing the Evil Wolf and Dragon Horse into the centre helps shore things up there somewhat, though still White has some unprotected Pawns to sort out. Meanwhile, Black is already pretty solid on the left and spends some moves further strengthening the defensive line on the right flank, by bring forward the Go-Between and Pawn on the 5-file to clear a space for the Phoenix to jump in.

121 EW-4l 122 SM-15d 123 DK-3m 124 FL-5c 125 S-4m 126 FL-4d 127 P-1j 128 N-2i 129 I-2j 130 VO-2g

Suddenly focus returns to the right side! Perhaps White saw a need to react to Black’s steadily strengthening formation. Black brings the Dragon King, Evil Wolf and Silver General to the party, providing some more backup to the Copper General that proved to be a target earlier on. White responds by forcing the issue, bringing the Knight and Violent Ox closer to the fray. Clearly a conflict is brewing!

131 N-1i 132 VO-3g 133 Ix2i 134 Px2i 135 Cx2i 136 S-5b 137 SM-2k 138 B-10c 139 SM-2j 140 EW-9e

As expected, a brief exchange flares up on the right side. Black’s Iron General takes White’s Knight, then White’s Pawn takes back, and Black’s Copper finishes off the Pawn. Black drafts in the Side Mover to protect the Copper, and we’re left with a somewhat perilous position with some holes in both sides’ flanks. White then moves an Evil Wolf out of the Bishop’s line of sight, adding some additional long-distance pressure to the right side.

141 C-12n 142 GB-5g 143 Bx2e+ 144 SMx2e 145 S-3l 146 FL-3e 147 S-2k 148 FL-2f 149 FL-6k 150 S-5c

Black again seeks to reduce White’s attacking potential on the right side, and suddenly elects to exchange Bishops on 2e, after allowing them to remain in a tense standoff for quite a few moves now. He then brings the Ferocious Leopard into play, stepping it methodically forward to add some strength to the Pawn formation around the 5- and 6-files. White also brings their Silver off the back line and into the battle on the right side.

One senses that the situation on the right flank is far from resolved….

151 EW-10l 152 S-5d 153 FD-2h 154 VO-3f 155 B-10m 156 P-4g 157 P-4j 158 S-4e 159 EW-4k 160 ST-2b

Sure enough, the tension continues to build on the right side of the board. Both players continue to march pieces forward into the growing tangle, with Black following White’s lead and bringing the Bishop to 10m to bear down on the fight from a distance.

These kind of long-range pressure tools are really helpful in Dai Shogi, and it can be easy for your opponent to forget that a piece is relevant to the local board situation even though it’s 10 ranks away! On such a big board, threats can easily fade into the distance. So during a large melee, be sure to double-check whether any long-range snipers are pointing at your pieces, too; you may need to think twice about starting a cascade of exchanges if some distant snipers might pick off whatever survivors you may have after the battle.

161 EW-3j 162 DH-10g 163 EW-4i 164 Bx4i 165 Px4i 166 DH-8e 167 DK7l-4l 168 S-5f 169 FL-7j 170 I-5b

As with normal-sized Chess and Shogi, in Dai Shogi it’s very easy to be tempted to jump into a tactical melee too early, when letting the tension build for a while longer would better allow you to prepare for the aftermath. Knowing *when* to drop the hammer is very important. Here we’ve had constant building tension on the right side, and both players have been restrained, making small exchanges but not overcommitting.

Black begins this passage of play by bringing forward their Evil Wolf. White can see that Black is building an array of well-coordinated pieces on the right side, and perhaps is preparing to launch a counterattack or lay the foundations of a breakthrough for the Dragon King on 3m. White decides to put a stop to this by launching the Bishop into the fray, taking out the Evil Wolf. Black recaptures with the Pawn, then White pivots the Dragon Horse back to point at this now-weakened Pawn. Black responds by committing his other Dragon King to the fight, sliding it over to 4l to support the Pawn.

Effective use of advancing Pawns is important in Dai Shogi, just as in Chu Shogi. Setting up long-range pieces behind the advancing Pawns is very typical and is often used to set up an advance down the side of the board.

171 EW-9k 172 I-5c 173 FL-6i 174 I-5d 175 R-1l 176 C-4b 177 R-3l 178 C-3c 179 Cx3h 180 I-4e

The strategic manoeuvres continue. Black brings his Ferocious Leopard nimbly around the Pawn formation on the 5- and 6-files, threatening a push of the Go-Between on 5i. A shift of the Rook over to 3l provides some additional strength bearing down on the 3-file, enabling the Copper to take the Pawn on 3h without breaking a sweat.

Meanwhile, White brings his Iron General all the way up to the front lines, perhaps sensing that Black may be preparing to launch the threatened counterattack.

181 GB-5h 182 G-6b 183 GBx5g 184 Sx5g 185 P-5i 186 C-2d 187 FD-3i 188 I-4f 189 FDx5g 190 Ix5g

Black makes good on their threat to push the Go-Between, then brings the Flying Dragon down to aim at White’s Silver General. White allows the exchange of the Silver for the Flying Dragon, although in my view this is a mildly favourable exchange for Black; the Silver is a stronger attacking piece as it can attack any forward square. The Flying Dragon can attack two squares away but only on the diagonal, so its attacking potential is more restricted.

After these small exchanges, some of the tension on the right side has been relieved. Black is probably pleased with the outcome, having reduced White’s amassed forces slightly and getting the Silver out of the mix. Black also has gained some ground here, and controls some useful squares with the advanced Pawns and the Copper on 3h, all backed up by strong pieces on the back ranks. White is still fine though, for the time being.

191 Cx4g 192 VO-3h 193 Rx3h 194 C-3e 195 P-5h 196 Ix5h 197 FLx5h 198 AB-4d 199 CS-4m 200 G-5c

Black wastes no time in trying to consolidate his positional advantages. The Copper draws first blood, taking out White’s other forward pawn. White responds by sending the Violent Ox headlong into the battle, which is promptly taken by the Rook. White again attempts to strike back with his Iron General, but Black’s Ferocious Leopard takes it out in return. In the end we see Black’s Copper still standing proudly on the front line, backed by the Ferocious Leopard and Rook, with Black’s long-range pieces still at the back ready to jump in if needed. Black has again made some gains of space in the process, leaving White a bit cramped on that right side. White is clearly keen to protect this flank and drafts in a Gold, calling it away from the King’s side to join the battle.

201 CS-5l 202 G-5d 203 DE-7m 204 G-4e 205 SM-2i 206 EW-9f 207 CS-6k 208 ST-3c 209 CS-5j 210 ST-2d

White, quite understandably, spends some time here further strengthening their defensive formation on the right. The Gold strides all the way to the front, with the Stone General sneaking up into the back of the formation. Black, meanwhile, marches the Cat Sword up to protect the Pawn on 4i.

Then Black does something a little surprising, and pulls the Drunk Elephant away from its defence of the King, presumably also headed toward the front lines on the right side. The Drunk Elephant is a strong piece, but is more typically kept on defence for the most part, so perhaps this move shows Black has confidence that King safety is not a concern in the immediate future.

211 GB-11i 212 P-8g 213 P-11j 214 FD-8f 215 FD-11k 216 I-13f 217 FL-11m 218 VM-13d 219 P-12j 220 VM-14d

Having established a strong foothold on the right side and drawn away some more of White’s pieces to defend, Black turns his attention to the left flank. Bringing forward the Go-Between and Pawn on the 11-file gains a bit more space, and some reshuffling of the Flying Dragon and Ferocious Leopard provides some more defence of the left-side Pawn line. White senses danger and brings the Vertical Mover over to support the Violent Ox parked on 14g.

221 FL-11l 222 P-1f 223 S-2j 224 FD-6h 225 DE-6l 226 Ky-6d 227 AB-11m 228 P-1g 229 DE-6k 230 DH-8f

Now White tries to shift emphasis a bit, and pushes forward in the centre. He drops the Flying Dragon into a safe square on 6h, then supports it with the Dragon Horse on 8f. Given Black’s strong positions on the left and right, a central advance can draw away some of Black’s defenders from their posts. At the same time, White shifts the Kirin over to 6d, perhaps in the hopes of getting it ready for a promotion to Lion should he be able to clear a path for it.

Black obliges, advancing the Drunk Elephant to support the Pawn on 6j, and shuffles the Angry Boar over slightly. Black is far from being in danger here, but it’s worth remembering that the departure of the Drunk Elephant leaves Black’s King more exposed than White’s.

Dai Shogi 420 -- Move 240 [Recovered]-01

231 R-3j 232 Ph-9d 233 FK-7k 234 Ph-7f 235 C-4h 236 P-1h 237 FL-6g 238 Ph-9h 239 EW-10j 240 GB-11g

White commits more forces to the centre now, leaping the Phoenix around until it’s perched on 9h ahead of the frontline Pawns. At the same time White brings the 1-Pawn ahead to sit menacingly on the head of Black’s Knight, but Black ignores this and instead brings the Ferocious Leopard forward and sets the Evil Wolf in defence of the Pawn on 9j.

White’s advance in the centre appears to be gathering pace. Now he has the Phoenix, a small front of protected Pawns, and a Free King all directed at Black’s centre. Black’s pieces are well-coordinated but the 8- and 9-Pawns appear somewhat weak in the face of White’s gathered forces. How would you respond?

241 P-6i 242 FD-5i 243 FK-8l 244 Px1i 245 Px1i 246 C-3f 247 P-6h 248 FDx4h 249 Px4h 250 N-13c

I’m assuming you probably didn’t guess, in response to my last question, ‘let White take a bunch of stuff’! Don’t blame yourself, I didn’t expect that either. But let’s remember that at this point in the game, Black is ahead on material by a reasonable amount, and the pieces White is threatening are not hugely important to Black’s overall plan. That being the case, Black lets White take the Knight and the Copper General, and in the meantime use his moves to gain a bit more space. Black takes the Flying Dragon back after it takes the Copper on 4h, so ultimately he’s down only a Knight, and that Knight was mostly stuck on the edge of the board facing down a large mass of White’s pieces. Letting it be taken enables a pawn push on the edge and further gains of space on the 6- and 4-files.

This exchange is a useful reminder that material value can be looked at differently in a game this large. Each player in a Dai Shogi game has 65 pieces in their starting army, so losing a weaker piece here or there for some positional compensation can be well worth it. Here, I believe Black decided that giving up the Knight for a bit of tempo and space would pay off in the end, and perhaps lead White to overextend as well. Dai Shogi is a deeply strategic game, so learning to judge when to accept a tactical loss for a strategic gain is a valuable skill.

251 EW-9i 252 Ph-11f 253 B-7j 254 FL-3g 255 Bx11f 256 GBx11f 257 P-12i 258 N-14e 259 P-12h 260 N-13g

Having let White have some fun on the right flank, Black decides to disrupt White’s central advance. Bringing forward the Evil Wolf pushes White to shunt the Phoenix to the side to avoid losing it, only for Black to take it with his Bishop. White immediately takes back with a backwards step from his Go-Between, but Black was probably quite pleased with this exchange; the Phoenix promotes to a Free King, one of the most powerful pieces in the game, whereas the Bishop is a great piece but well worth sacrificing to eliminate White’s chance at a second Free King. Black follows up by pushing the 12-Pawn, creating a little bit of counter-play.

261 P-15j 262 C-12b 263 P-15i 264 C-13c 265 P-4g 266 C-13d 267 P-14j 268 FL-10c 269 P-13i 270 DH-8e

Black continues the forward press, advancing Pawns on the 13-, 14- and 15-files, as well as on the 4-file. Black wants to continue to gain space along the flanks, which serves to increase his own options while cramping White’s ability to manoeuvre. White responds by bring his Copper from the back line to support the Pawns on the left flank, then shuffles his Dragon Horse back one square; this way it continues to protect the Pawn on 8g and the Evil Wolf on 9f, but also pins Black’s Ferocious Leopard on 6g to the Rook on 3j. Not a particularly strong pin, mind you, but still something Black should keep in mind if that Rook is important to his plans on the right side.

271 P-13h 272 N-12i 273 VMx12i 274 EW-8f 275 VM-12j 276 EW-7d 277 BT9n-8n 278 EW-6e 279 CS-6i 280 ST-1e

Now both players get into some more subtle repositioning. Black’s Pawn push to 13h forces White’s Knight to jump, although ultimately it’s a bit of a waste as the Knight is immediately taken by the Vertical Mover on 12i. White retaliates by moving the Evil Wolf to 8f, which opens a line from the Dragon Horse toward the Vertical Mover, which Black promptly drops back to 12j. White’s other Evil Wolf then shuffles toward the right flank, while Black finally accepts the need for King safety and moves a Blind Tiger over to cover the space abandoned by the adventurous Drunk Elephant.

281 FL-12k 282 VO-14h 283 I-13j 284 VOx13h 285 I-12i 286 VO-14h 287 FL-13j 288 VOx14j 289 VOx14j 290 VMx14j

Suddenly the left flank explodes into action! White advances the Violent Ox down the 14-file, then gobbles up a Pawn on 13h. Black threatens to recapture with the Iron General, pushing the Violent Ox back to the 14-file. White’s Ox then leaps into battle, taking a Pawn, getting taken in return by Black’s Ox, then White’s Vertical Mover takes Black’s Ox. The 14-file is now mostly open, and White appears to have made a dent in Black’s lines for the first time.

291 R-14l 292 ST-2f 293 Rx14j 294 AB-13c 295 GB-11h 296 C-2g 297 CS-5h 298 C-3h 299 SM-6i 300 FL-9d

Fortunately for Black, the excitement is short-lived. Black brings the Rook forward and takes White’s Vertical Mover on 14j; this leaves White’s Cat Sword on 14c vulnerable to capture, so the Angry Boar shuffles over to protect it. White then changes tack, advancing his Copper toward the front on the right side. Black responds calmly, bringing his Side Mover over in defence of the Pawn and Ferocious Leopard on the 6-file; this helps deter any ideas of the Dragon Horse on 8e breaking through to join the fight on the right.

301 P-11i 302 FKx10k 303 FK-11l 304 FK-8k 305 P-8i 306 FL-4h 307 DKx4h 308 C-3g 309 DK4h-4l 310 VM-3f

White now makes a serious play down the centre. His Free King, having sat quietly on 10f for a large portion of the game, darts downward and takes the Pawn on 10k! This is clearly a dangerous development, so Black sweeps his own Free King over to 11l and offers an exchange. White refuses and parks the Free King on 8k, pinning the Blind Tiger to Black’s King.

While this looks deadly, for the moment Black can breathe easy; the Free King is in a dominating position but has no support. The King can only be attacked via the diagonal on 10m, and that square is amply protected. So, for now at least, the Free King bears down on Black’s camp but doesn’t present any immediate checkmating threats.

311 S-9n 312 FL-9e 313 SM-13k 314 FK-5n 315 VM-11j 316 CS-3d 317 VM-10j 318 P-10f 319 P-15h 320 EW-5f

Black once again stays cool under pressure. First, he brings the Silver into position on in, plugging the one remaining hole in the King’s castle. Then he shifts the Side Mover up to 13k, preparing for a discovered attack on White’s Free King via a move of the Flying Dragon. White sees this coming and sweeps the Free King down to 5n, where at the moment none of Black’s pieces can threaten it. Black then acts to plug more holes in his defences by bringing the Vertical Mover over to protect the 10-file. Meanwhile, White has advanced the Copper General and Evil Wolf down the right side, perhaps hoping to reverse some of Black’s space gains there.

321 N-13m 322 G-10b 323 P-15g 324 EW-5g 325 I-13h 326 EWx5h 327 SM-6j 328 VM-3e 329 I-14g 330 I-13g

At this point Black remembers he has a Knight on 14o that hasn’t been developed yet, so he brings it into play. Similarly, White decides to draft the other Gold General into action, drawing it away from the stationary defence of the King.

From here we have a scenario that by now is somewhat familiar in this game: Black moves to consolidate his gains of space, while White opportunistically captures on 5h. Black is still ahead in material, having captured 25 pieces to White’s 22 captures, so the loss of an Ox is not particularly bothersome. The increasingly cramped nature of White’s position leaves Black with more options.

331 P-12g 332 C-14e 333 P-15f 334 Px15f 335 Ix15f 336 C-13f 337 R-14e+ 338 SM-13d 339 I-15e+ 340 RCx15e

Finally Black decides to cash in his hard work along the left side and mounts an edge attack! A final Pawn push on the 15-file triggers a Pawn capture from White, then a recapture from Black’s Iron General. This opens up a spot for Black’s Rook to dart forward to 14e and promote to Dragon King. White takes Black’s Iron General with his Reverse Chariot, but Black is sitting pretty with a Dragon King in a threatening position in the depths of White’s camp.

341 RCx15e+ 342 Lx15e 343 Lx15e+ 344 R-1c 345 +L-15k 346 EW-9f 347 FL-12i 348 P-5f 349 N-14k 350 DH-11b

A second flurry of captures along the left edge finally settles matters: Black ends up ahead, with a Lance now promoted to White Horse. Black then pulls the White Horse back to 15k, where it remains in control of the file while exerting additional pressure on White’s centre via the diagonal. White tries to keep a handle on the situation and prevent any incursions by Black’s newly-minted Dragon King; he brings the Rook back to 1c to guard the third rank and swings the Dragon Horse back to 11b to protect the Side Mover on 13d.

Black seems to have chosen a good moment to break the tension on the left side; he ended up ahead in material, with a two strong promoted pieces remaining in control of the area. White does have a strong wall of pieces blocking further progress by the Dragon King, but as of now none of them can threaten this powerful piece directly.

351 P-8h 352 SM-10d 353 +L-14j 354 SM-10e 355 N-15i 356 P-5g 357 N-14g 358 DHx14e 359 FLx5h 360 Px5h

White elects to respond by pulling the Side Mover away from the dangerous Dragon King, and uses it to reinforce the centre. Black continues to exert pressure from a distance via the White Horse, and starts moving the Knight forward along the 14- and 15-files. Unfortunately this exposes the Dragon King to capture for a moment, as the Knight blocks the White Horse’s protection; White wastes no time in taking the Dragon King off the board. A lucky escape by White?

361 P-4f 362 G-5f 363 P-7h 364 Ky-6f 365 EW-8i 366 R-8c 367 FK-8l 368 FL-8f 369 P-9i 370 R-8d

Black now moves to take advantage of his gain of initiative. He advances some more Pawns to gain more space and create some tension in the centre and on the left side, and his Free King which has been sat quietly off to the side for quite a while finally awakens and provides backup for the central Pawns. White responds by bringing forward his Gold and Kirin on the right and swings the Rook over to the 8-file to help protect the centre.

At this point quite a lot of tension has built along the central files, but neither player has yet pulled the trigger. Both are manoeuvring carefully to prepare for the inevitable clash.

371 FD-13m 372 GB-11g 373 GBx11g 374 FKx12g 375 FL-11h 376 FK-15j 377 SM-13j 378 SM-9e 379 GB-11f 380 FKx11f

Now White mounts a rescue operation of sorts, aiming to recover his Free King from its imposing but ultimately useless post all by itself near the Black castle. Triggering an exchange of Go-Betweens on 11g allows the Free King to dash back out of Black’s camp, and after a brief shuffle where it is threatened by Black’s Ferocious Leopard, the Free King is now back in the game and has picked up a Pawn and a Go-Between along the way.

The Free King is very powerful, particularly on a board this large where mobility is paramount, so rescuing it and putting it into service protecting the centre certainly seems prudent. But will it be enough to deter Black’s determined advance down the middle of the board?

381 FL-11g 382 FK-8c 383 FLx10f 384 SM-8e 385 FK-8k 386 R-15d 387 FD-15k 388 CS-13d 389 Ph-7i 390 P-12f

As it happens, White does quickly get the Free King back to base, and points it directly at the endangered 8-file. Black finds a new means to menace the centre and curls the Ferocious Leopard up and around, gobbling up a Pawn and forcing the Side Mover to shuffle away. Black’s Free King steps up slightly to offer its protection to the Flying Dragon on the left edge. Now the stage appears to be set for a showdown on the central files.

391 DK-12l 392 P-12g 393 SM-13k 394 AB-14c 395 P-9h 396 P-12h 397 FLx9g 398 FLx9g 399 Px9g 400 EW-8f

Yet more tension building up in the centre. Black swings a Dragon King across the fourth rank to gain some control of the 12-file, while White advances the 12-Pawn forward to interpose itself in the White Horse’s line of fire. Meanwhile Black pushes forward in the centre, triggering an exchange of Ferocious Leopards, which then forces White’s Evil Wolf to the side and off the 9-file.

401 EW-9h 402 FK-11f 403 EW-10g 404 FKx11i 405 Ky-10l 406 Kyx4f 407 EW-9f 408 EWx9f 409 Px9f 410 FK-8f

Now, at last, the war in the centre kicks off. Black’s Evil Wolf steps into the fray, threatening White’s Free King, which then takes the Pawn on 11i. The Evil Wolves are exchanged in the centre, drawing White’s Free King right into the middle of the action. After these quick exchanges, the centre is already much more open than it was just a few moves ago.

411 DK-9m 412 Ky-4h 413 DE-5j 414 Kyx6h 415 Ph-6i 416 Kyx8h 417 P-9e+ 418 SMx9e 419 VM-10d+ 420 Cx14g

We’re getting into the endgame now! The board is wide open, and the last few remaining long-range pieces have a great deal of mobility. King safety will start to become an issue now, as threats may pop up virtually anywhere on the board with little warning. Those short-range pieces with strong promotions become really dangerous now, as there’s a real chance they can reach the promotion zone and overwhelm the King’s remaining defences.

Black starts the action by bringing over the other Dragon King from the right side, bearing down on the 9-file. White’s Kirin starts to advance, offering threats not only of captures but of possible promotion to a Lion. Black ensures his Drunk Elephant, Side Mover and Phoenix hold the line, forcing White’s Kirin to detour toward the centre.

Then Black pulls off a nice tactical ploy: pushing the Pawn on 9e and promoting coaxes a recapture out of White’s Side Mover. This conveniently blocks the diagonal from the Free King to 10d, allowing the Vertical Mover to promote to Flying Ox on that square! The Flying Ox is very powerful, able to move freely in every direction except sideways. Black has punched a hole through the centre and now has a very dangerous piece perched right above the White King’s castle. White seems to be at a loss, and rather than try to address this problem advances a Copper on the left flank.

421 DKx9e+ 422 FKx9e 423 +VMx9e 424 DHx8k+ 425 SMx8k 426 C-13h 427 Phx8g 428 Ky-10h 429 Ph-6e+ 430 G-5g

Now White’s situation is extremely dire. Black shunts his Dragon King forward to promote to Soaring Eagle right next to his Flying Ox, placing White’s Free King in the firing line. White is forced to take immediately, because a Soaring Eagle with its Lion Power is simply too dangerous to be allowed to roam near the increasingly vulnerable King. Black of course takes the Free King, giving him a very significant material advantage.

White retaliates by taking Black’s Free King with his Dragon Horse, promoting it to Horned Falcon in the process, but Black does not mind; his Phoenix is about to replace it. Sure enough, after taking White’s Horned Falcon with his Side Mover guarding the fourth rank, Black marches his Phoenix forward and gains a new Free King as it promotes.

431 +VM-8f 432 Ky-10f 433 +Ph-2a

Now Black starts setting up the kill. He brings the Flying Ox onto the 8-file, pinning the Drunk Elephant to the King. White desperately calls back his Kirin to threaten it, but Black simply sends his Free King to White’s back rank to check the King — the first check of the game, only 431 moves in (!!).

434 BT-7a 435 +VMx7e

To evade the check White brings the Blind Tiger back to 7a, blocking the Free King’s attack. The Flying Ox then steps away from White’s Kirin, focussing its gaze on the Blind Tiger and pinning it in place.

Black now threatens checkmate on 7a, if the Free King slides over and takes the Blind Tiger, but then the Drunk Elephant would be free to recapture it. To enforce mate, Black needs to find a way to pin the Drunk Elephant as well.

436 G-4h 437 DK-12j 438 C-12i 439 DK-8j

With White’s forces scattered and helpless, Black’s task turns out to be relatively straightforward. Black brings his Dragon King up to the sixth rank, deftly evades a last-ditch threat from White’s Copper General, and slides over to the 8-file, enforcing a pin on White’s Drunk Elephant.

440 Ky-10h 441 +Phx7a

The final moves are just a formality at this point, but White is a good sport and lets Black achieve checkmate on the board rather than resigning. After one final pointless Kirin move, Black fires the Free King onto 7a and it’s checkmate — all the King’s defences are pinned in place, and there’s no escape!

I can’t speak for you, of course, but I very much enjoyed analysing this game. Both players fought hard throughout, and in truth the mistakes White made were relatively minor. A few positional overreaches, some needless captures here and there, and that was enough to let Black build up a positional advantage that eventually became insurmountable. White did cause Black some panic here and there, but ultimately Black’s control of space and carefully-judged attacks won the day.

I hope this game can demonstrate to some of you out there that Dai Shogi is a phenomenal game that does bring some things to the table above what Chu Shogi offers. Yes, the game is longer and slower, but in return you get a deeply strategic, positional game that is epic in scope. The larger board affords tremendous flexibility in how you approach every stage of the game, and despite the sheer size of your army every piece has a role to play. As a result, even when the Lions disappear off the board as in this game, plenty of taut excitement remains for the taking.

From here, I hope you’ll seek out some games of Dai Shogi for yourself, or even challenge me to a game, perhaps. There’s something special about playing such an ancient and rich game that once was the most prestigious version of Shogi in medieval Japan; when I play, I feel like I’ve stepped back in time, to an era when we didn’t have to rush through every leisure activity, and spending a day or two on a drawn-out battle of small pentagonal wooden pieces was a perfectly sensible way to spend our days. Luckily we still can enjoy this centuries-old treasure today, and it’s a useful and stimulating distraction during this terrible period in history we find ourselves in.

Now that I’m back in the blogging mood, I’m planning to analyse a Chu Shogi game as well (finally), and then I’ll take on Wa Shogi, the only large Shogi variant that uses drops as in modern Shogi. In the meantime, I hope anyone out there reading this is staying safe and healthy.

Tagged Dai Shogi, Shogi, Shogi Variants

Apr 13 2020

10 Comments

Games, Shogi

Dai Shogi, Part I: How to Play

Following on from my previous two posts about Chu Shogi (Part I, Part II), I plan to provide a full annotated Chu Shogi game for you. This is still in the works, but Chu Shogi games are long, so that post will take quite a while to prepare.

In the meantime, I’m going to work in parallel on material for other historical Shogi variants. Today I’m going to introduce you to Dai Shogi, Chu Shogi’s big brother and one of the earliest forms of the game. Dai Shogi is often given short shrift by the Shogi variant community, who largely dismiss it as a slower, more boring version of Chu Shogi; hopefully by the end of this post I can convince you that this isn’t a completely fair characterisation.

One of the advantages of learning Dai Shogi is that if you know Chu Shogi, you can learn the basics of Dai Shogi in no time at all. That means this post will be a bit more concise than the last two. However — excuse me while I put this in bold type on a separate line for emphasis —

You must know how to play Chu Shogi in order to make sense of this post!

Now that’s out of the way, let’s get started!

The Origins of Dai Shogi

As mentioned in the first Chu Shogi article, we are aware of a large version of Shogi dating all the way back to the mid-12th century. In the latter part of the 12th century the Nichureki was published, and this document describes an early form of Dai Shogi now generally referred to as Heian Dai Shogi.

Heian Dai Shogi was played on a 13×13 board with 34 pieces per player, with 13 types of pieces available. Much of the board was therefore empty, and the pieces moved slowly for the most part, so most attempts at reconstructing this game find it to be rather glacially paced.

However, clearly the Shogi playing community of the time realised this fairly early on, and various diary references to Dai Shogi in the 14th century suggest it was a well-regarded game, so we suspect that the game evolved into its more robust 15×15 form by that time. Dai Shogi is presented in detail alongside Chu Shogi in the Shōgi Rokushu no Zushiki (象棋六種之図式), originally published in 1443, which you can see below:

During the 15th century Dai Shogi was considered the most distinguished form of the game, as described by George Hodges:

“Large Shogi eventually became popular enough to be referred to simply as ‘Shogi’…. Similar references abound throughout the 15th century, and indeed many imply that Little Shogi was generally regarded as merely a boys’ game.”
–George Hodges, Shogi Magazine

Dai Shogi eventually lost popularity to Chu Shogi, which offered a lot of the same ingredients in a tighter package. Chu Shogi was then the dominant form of Shogi until the late 16th century, when the introduction of the drop rule in Sho Shogi (small Shogi) turned the Shogi world on its head. From that point onward, Dai Shogi largely vanished from the Shogi world, although we know it was still being played into the 19th century as it appears in a few famous woodcuts around that time.

Dai Shogi today has experienced somewhat of a revival, though much less so than Chu Shogi or Tenjiku Shogi. Dai Shogi can be purchased and played relatively easily today largely thanks to the efforts of George Hodges, who disseminated information on Shogi variants around the Western world in the 1970s and 80s. While in today’s fast-paced world a full game of Dai Shogi can be tough to organise, thanks to the efforts of dedicated Shogi fans worldwide there are still ways to get a game going via the internet or in real life.

The Rules

As you might expect from a game I keep calling ‘Chu Shogi’s big brother’, Dai Shogi is played on a bigger board: 15 x 15, with 225 squares, substantially larger than Chu Shogi’s 12 x 12 board with 144 squares. Of course the starting armies are larger too; each player begins with 65 pieces of 29 different types, which is again a significant increase from Chu Shogi’s 46 pieces per player of 21 different types. Including promotions Dai Shogi requires you to remember 36 different moves, a decent step up from 28 in Chu Shogi.

The starting position of a Dai Shogi game looks like this:

Diagram 1: Dai Shogi board with 2-kanji pieces.

There’s clear similarities here to the Chu Shogi setup: two Go-Betweens at the front, then a complete row of pawns, then a massive army lurking behind with the King at the very back. However, because Dai Shogi has an odd number of files, the King can sit directly in the centre on the back rank.

Here is the initial position with all pieces flipped over to show their promoted sides:

Diagram 2: Dai Shogi board with pieces flipped to show their promoted sides (2-kanji pieces).

Just like in Chu Shogi, only the Lion, Free King and King don’t promote. If you look closely you may notice a bunch of pieces promoting to Gold General — more on that later.

Now let’s zoom in and look at one player’s starting setup in detail, this time with 1-kanji pieces for better readability:

: Diagram 3: Dai Shogi initial position for one player (1-kanji pieces).

: Diagram 4: Dai Shogi initial position for one player, with pieces flipped to show their promoted sides (1-kanji pieces).

If you look more closely at Diagram 3, you will notice that the pieces are shuffled around somewhat compared to Chu Shogi. The central position of the King is a bit more convenient, particularly given that the King starts already ensconced in a Basic Castle (two Blind Tigers and a Drunk Elephant in front, and flanked by two Gold Generals). The Free King and Lion are now in two different rows, and to either side of them are several new pieces. More new pieces are sitting close to the left and right edges of the board on the first and fourth ranks. When we look down at Diagram 4, we can see that all of these new pieces promote to Gold General. Along with these eight new piece types, Dai Shogi contains every piece type that is in Chu Shogi, and they have identical promotions in Dai as well.

The Basics

Rather than go through all the basic rules in full, which are nearly identical to Chu Shogi, I will just mention the key points:

Objective: The goal of the game is to capture all of the opponent’s royal pieces — their King or Crown Prince (if applicable). If a player has both a King and Crown Prince on the board, both must be captured for the other player to win. A player may also win by eliminating every non-royal piece from their opponent’s army (the Bare King Rule).
Making Moves: Black (at the bottom of the board in our diagrams) always moves first. Players take it in turns to move one piece in their army in accordance with its movement abilities. Pieces may not move into or through squares occupied by friendly pieces. If that player’s piece moves into the same square as an opposing piece, that opposing piece is captured and removed from the game. As in Chu Shogi, there are no drops in Dai Shogi; captured pieces are removed from the board and play no further part in the game afterward.
Promotion: If a player moves a piece in their promotion zone — which in Dai Shogi consists of the five furthest ranks from that player’s starting position — they may choose to promote that piece by flipping it over. That piece now becomes a different piece, as indicated by the characters on the promoted side. Once a piece is promoted it may not un-promote. If a player chooses not to promote a piece on its initial move into the promotion zone, the piece may promote on a subsequent move if it A) moves out of the zone, then back in, or B) captures an enemy piece within the zone.
If a player chooses not to promote a piece and that piece reaches a point where it can no longer move, then that piece simply becomes a ‘dead piece’ and sits in place for the rest of the game, or until it is captured. This applies to pieces that cannot move backwards, like the Stone General, Knight, Lance, and Pawn.
Repetition: Repeating a board position with the same player to move is forbidden. This is more strict than the official rules for Chu Shogi, which allow four repetitions. Wikipedia claims that this rule does not apply when a player is in check. A player may pass their turn using the Lion’s abilities, but two passes in a row are not possible in Dai Shogi, since that would create the same position with the same player to move.
Lion-Trading Rules: There are no Lion-trading rules in Dai Shogi! The larger board means the Lion doesn’t dominate quite so much as in Chu, although the Lion is still very dangerous in endgame situations.

The New Pieces

To learn Dai Shogi, we also need to learn the moves and promotions of the eight new pieces. These new pieces are quite easy to remember:

: Diagram 5: The eight new pieces of Dai Shogi (2-kanji pieces)

: Diagram 6: The eight new pieces of Dai Shogi (1-kanji pieces)

There’s a few key points to note with these new pieces:

The Knight is back — Players of standard Shogi may have noticed there were no Knights in Chu Shogi, but the Knight has returned in Dai Shogi. The Dai Shogi Knight moves like a Chess Knight, but only forward.
Longer-range weak pieces — Two of the new pieces, the Violent Ox and the Flying Dragon, are unique in that they are the only short-ranged pieces that can move 1 or 2 spaces in certain directions. This can be helpful when facing off against an opposing group of weak pieces, as they exert a slightly larger influence across the board.
Simple promotions — All eight pieces promote to Gold General. This means promotion is a little less exciting than with some other short-range pieces, but nonetheless a Gold General is a useful defensive piece due to its good coverage of adjacent squares, and a powerful checkmating threat when near the enemy King.

All of these pieces promote to Gold General, but not all of them have strictly upward-compatible moves; in other words, some pieces’ unpromoted moves are not a subset of the Gold General’s moves, meaning that you may not want to promote them in certain circumstances.

Upward-compatible pieces: Stone General, Iron General, Evil Wolf, Angry Boar
Non-upward-compatible pieces: Knight, Cat Sword, Violent Ox, Flying Dragon

The upward-compatible pieces, however, should always be promoted. Becoming a Gold General substantially increases their movement powers, so there’s no reason to leave them unpromoted.

If you know Chu Shogi, then getting to grips with these pieces should be very easy for you. They all have simple moves and the same promotion. To make things even easier for you, I’ve created reference sheets for all the Dai Shogi pieces in two versions: dai-shogi-reference (1-kanji) and dai-shogi-reference (2-kanji). Click the links to download PDF versions, or click the thumbnails below for very high-resolution PNG images.

: Dai Shogi reference sheet (1-kanji pieces)

: Dai Shogi reference sheet (2-kanji pieces)

Why play Dai Shogi?

Amongst the admittedly small Shogi variant player community, Dai Shogi has a reputation for being just a slower and/or more boring form of Chu Shogi. When looking for information on the game, one will frequently stumble on comments like this one, taken from the ChessVariants.com page for Dai Shogi:

“The extra pieces are rather weak, and promote to the also weak Gold General. As a result of this, and due to the longer time it takes the many steppers to cross the larger board, Dai Shogi is a much slower game than Chu. It is thus not surprising the latter quickly surpassed Dai Shogi in popularity.”

Or this comment buried within the Chu Shogi page on Wikipedia:

“As stated earlier, this game is based on dai shogi and all of the pieces of this game can be found in dai shogi. The eight types of pieces that were removed were all rather weak and all promoted to gold generals. Furthermore, the larger board of dai shogi makes the slow-moving step movers even slower. All of this made for comparatively dull gameplay.”

I cannot stress enough that I strongly disagree with this assessment. Dai Shogi is definitely a longer game, generally speaking; a typical Chu Shogi game might last 300 moves, whereas a Dai Shogi game can reach 400-500 moves, or sometimes substantially longer. Here is the final position of a game I played online that I won after 568 moves:

dai-shogi-aftermath-568moves copy

When you see a number as large as that, you may be turned off. But that final position shows how violently thrilling a good Dai Shogi game can be. My 65-strong starting army was whittled down to only 16 pieces, and this was due to some extravagant piece sacrifices throughout the game to gain positional advantage and a series of bloody exchanges. During the game my Lion captured about a dozen opposing pieces before finally being dispatched. If you look at my castle at the bottom of the board, you can see the final desperate lunge of my opponent’s last-minute attack before I finally clinched the victory. So yes, the game was long, but it was a nail-biter throughout. After that game I could never call Dai Shogi ‘boring’ or ‘slow’.

I should be clear that I would still generally recommend Chu Shogi over Dai Shogi — Chu is tighter, shorter, and just a devastatingly good game. But compared to Chu Shogi, Dai Shogi offers a new experience — more intricate and strategic, while losing none of the tactical complexity of Chu. In fact, I propose there are some significant advantages to Dai Shogi for the aspiring Shogi fanatic:

Bigger board, bigger armies: Yes, having a larger board does lengthen the game, and there are more pieces to remember. But the larger board also opens up more strategic flexibility. Openings are less sharp than in Chu, and you have more time to build up an attacking force and prepare your defences. The larger army also makes the game a bit more forgiving — early mistakes can be mitigated more easily, as individual pieces are less impactful on such a large board.
Convenient starting array — Dai Shogi has an odd number of rows and columns on the board, unlike Chu, so the starting position is more symmetrical. The King begins in the dead centre on the back rank, and he starts the game already in the Basic Castle formation we know and love from Chu. That means it is viable to simply leave the King where he is and focus your opening on developing your attacking pieces, rather than spending moves on collecting your defensive pieces together. The new short-range pieces also start the game closer to the front lines, so gathering your forces to the front is not too onerous. In general the starting formation feels very carefully and cleverly designed, and it enables opening play to maintain a good pace, without much need for back-rank defensive reshuffles.
No Lion-trading rules — The ChessVariants.com page on Dai Shogi appears to cite this as a negative, bizarrely. The Lion-trading rules in Chu Shogi, while they serve a very important purpose and definitely benefit the game, are also difficult to learn, filled with weird exceptions, and at times counter-intuitive. Dai Shogi can dispense with them entirely, since the Lion is still powerful here but not totally dominant, and that means we get to enjoy its powers without worrying about any rules-lawyering being needed in unusual board situations.
A nice stepping-stone to larger games: Dai Shogi is far from the biggest form of Shogi. I will cover these in later articles, but you can see a bit of information on the larger Shogi games in my introduction to Shogi. Most of these larger beasts are very significant leaps in complexity from Chu Shogi; Dai Dai Shogi, for example, has 64 types of pieces in the starting position, compared to 21 in Chu Shogi. Dai Shogi brings some of the benefits of these larger games — greater strategic scope, more expansive opening strategies — but can be easily learned in an afternoon if one already knows Chu Shogi. This makes Dai Shogi an ideal introduction to the large Shogi games, which beyond simply being immense, are actually well-designed and fascinating games to play.

So, taking all those points into account, I do believe Dai Shogi offers something of its own character. Dai may not have the extravagant piece variety of Dai Dai Shogi, or the all-powerful Emperor of Maka Dai Dai Shogi, but it does offer a compelling, strategic gameplay experience without much more mental overhead than Chu Shogi. Dai Shogi is by any measure an extremely large member of the Chess family, yet it manages to be so without becoming unmanageable. I’d even say that in some ways it may be more forgiving for beginners than Chu Shogi, given that mistakes hurt a bit less here and opening play is more freeform, and not needing to learn the Lion-trading rules is a nice bonus.

R. Wayne Schmittberger, perhaps one of the most experienced large Shogi players in recent history, does prefer Chu Shogi but offers this endorsement of Dai Shogi’s attractions:

“The extra space between the starting forces and the greater number of pieces permit greater flexibility in playing the opening than in Chu, and hence greater scope for creativity.”

Ultimately, it’s technically true that Dai Shogi is basically ‘Chu Shogi, only bigger’, but I would emphasise that the game offers greater scope for strategic intrigue and complexity — and yet still remains comprehensible. In that respect I think it has a character all its own, and is well worth taking the time to explore.

Basic tips for beginners

To be perfectly honest, there’s not a whole lot of information out there about how to play Dai Shogi at a high level. However, the game’s similarity to Chu Shogi at least offers a strong starting point. What I will do here is highlight some key points of Chu strategy, and describe how to adapt them to Dai Shogi; I will also talk a bit about how to utilise the new pieces.

The Opening

As mentioned above, the opening in Dai Shogi is a bit more freeform than in Chu Shogi, thanks to the larger board area. However, the same opening principles used in Chu Shogi can be usefully applied here:

Don’t neglect your short-range pieces: In Dai Shogi you have a wider Pawn line, so be sure to bring forward some of your new short-range pieces to fortify your Pawns. As in Chu Shogi, any weak points in your front line will be vigorously attacked by the opposing Lion, so try not to allow any obvious weaknesses to develop. Out of the eight new pieces, the stronger ones — the Flying Dragon, Violent Ox, Evil Wolf, and Iron General — can be used as active attackers as you steadily advance your Pawn line. The weaker ones — the Stone General, Angry Boar, Cat Sword and Knight — are still valuable up front, but more for force of numbers than as the vanguard. Knights in particular are easy to lose by mistake, as they jump forward relatively quickly but in a very limited way; advance the Knights carefully, and avoid jumping them into positions that reduce their already limited mobility.
Keep your King safe: The King starts in a Basic Castle from move one, so rather than shuffling around your pieces to form a castle you can instead focus on fortifying this pre-existing structure. As in Chu, bolstering that formation with your Silvers, or even with your Dragon Kings or Dragon Horses can be useful.
Place your Lion high and central: Despite the somewhat weaker influence of the Lion in Dai, and its greater susceptibility to capture due to the lack of anti-trading rules, the Lion is still well-placed at the front of the action. Use your Lion to stake a claim to the centre and exert its influence as strongly as you can. The Lion can easily exploit weaknesses in the enemy front line to claim some quick material gains, and its presence can force the enemy to channel their forces away from the centre, allowing you to fortify your defences on the appropriate side of the board. Just be aware of the threat of a Lion trade if your opponent gets fed up; sometimes you may want to jump the Lion behind the Pawns to fortify your front line whilst staying out of trading range.

The old Lucky Dog Games site on Dai Shogi has some sample openings, which I’ve diagrammed below for your convenience:

Diagram 7: Position after 1.P-9j P-7f 2.P-7j P-9f 3.DH-12n DH-9g 4.EW-10l Ln-9e 5.P-10j Ln-8g 6.P-6j P-4f 7.Ph-9k P-3f 8.Ph-10k EW-6d 9.EW-9k EW-7e 10.Ln-6k P12f

In this position we see a fairly solid early opening from both sides, with several central Pawn advances backed up by the Lion. Both players have brought their Evil Wolves forward as well to reinforce the advanced Pawns. The centre looks set to be a stage for some Lion manoeuvring; the later stages of the opening may see the players developing an attacking posture on one side of the board, leaving the Lions and Wolves to battle over the centre.

Diagram 8: Position after 1.P-9j P-7f 2.DH-7i P-9f 3.EW-10l Ln-9e 4.EW-9k Ln-8g 5.EW-8j Ln-10i
6.Ln-9k Lnx11j-12i 7.N-13m P-8f 8.P-6j Ky-7e 9.P-4j P-6f 10.P-3j Ph-8c

Here White has jumped the Lion directly into the action, capturing a Go-Between on the left side in the process. Black has chosen to lock down the centre instead, with a well-placed Lion and an Evil Wolf and Dragon Horse advanced as well. The advanced Pawns on the right suggest Black may be planning to develop an attack along this flank.

Granted this is very early in a Dai Shogi opening — an opening in this game can easily last 100 moves or more — but at this stage I feel Black is more solid. White’s Lion has made a small material gain but is unprotected and could be harassed, allowing a further gain of tempo for Black. Black meanwhile has an early hold on the centre and has moved various pieces rather than jumping the Lion all over the place, giving them better piece development overall.

Diagram 9: 1.P-13j P-7f 2.FD-12j Ln-7e 3.P-10j Ln-8g 4.Ln-10k Ln-6i5.P-14j P-9f 6.VO-14k Lnx5j-4i 7.N-3m DH-7g 8.Ln-8i P-10f9.B-9j FD-12b 10.R-14l P-12f

In this position White has again spent several tempi unleashing the Lion, this time grabbing a Go-Between on the right side. Black is clearly developing an attack along the left side, having advanced a Violent Ox backed up by a Rook. Black again holds the centre, this time with a Lion protected by a Bishop. The Lion’s influence also helps restrict White’s Dragon Horse.

Again I’d suggest Black has made better use of their early turns here. White’s Lion does restrict Black’s development along the right side, but Black has already made gains of space on the left and can freely develop their attack over there. Black’s Lion is dominant in the centre, and they are strong on the 14th file as well.

Diagram 10: Position after 1.P-9j P-7f 2.P-8j P-9f 3.P-6j Ln-9e 4.Ln-8k DK7d-8c 5.P-3j EW-7d
6.DH-4n P-8f 7.EW-6l EW-8e 8.B-7j N-3c 9.GB-5i P-4f 10.EW-6k P-8g

Finally, in this last example both players have advanced in a more cautious way. Both Lions are centrally placed and protecting the Pawn line. Both have brought their Evil Wolves forward to support Pawn advances. Neither player has obvious weaknesses; Black appears to be preparing an advance on the right side, whereas White is advancing in the centre, perhaps to prepare a higher Lion placement.

These opening positions are instructive examples of the extremely varied play that is possible in the Dai Shogi opening. Despite the larger board, players can exert pressure quite early in the game, forcing the opponent to commit their attacking forces to one side or another. Piece placement can vary enormously depending on players’ particular style, so maintaining flexibility is important. As in Chu, advancing the weaker pieces is critical to developing a strong attacking posture, and those pieces should serve to reinforce your Pawn line. As we can see in these examples, the Evil Wolf is a useful piece to develop in the early going, and is conveniently placed to support early Pawn advances.

The Middlegame

The middlegame of Dai Shogi is a spectacularly complicated affair, so it’s difficult to offer much more than very basic concepts here. In general, we will apply the principles we learned in Chu Shogi, while bearing in the mind the consequences of the larger board:

Advance methodically: Perhaps even more true in Dai than in Chu. Your army has a larger and more varied array of short-range pieces, including two that have a two-square movement range (the Flying Dragon and the Violent Ox), so be sure to advance these on the front where you are developing your attack. On such a large board it’s hard to resist the temptation to advance your Pawns quickly to get things going, but try not to fall victim to that impulse. A solid Pawn line supported by your stronger short-range pieces — Evil Wolves, Violent Oxen, Flying Dragons, Iron Generals, Copper Generals — will gain you space much more effectively than a hurried Pawn push with little support. The Lion is slower in this game but still has an insatiable appetite for Pawns and Go-Betweens!
Avoid pointless material losses: This is another general Chu Shogi principle that works well in Dai. Patience is a virtue here, and even though the larger armies make individual material losses less impactful, at some stage you will need to exert force on some part of the board to gain space and cramp your opponent’s defences; doing so is much harder if you lack the numbers. If you do end up down in material, avoid major exchanges of pieces; instead, try to gain enough space to promote some pieces, which can make up for the lost material value. Conversely, if you hold a material advantage, try to force an exchange; this will open up lines of attack, but your material edge will ensure you are better able to exploit this new space than your opponent.
Don’t rush toward promotion: The bigger board of Dai means that gaining space all the way to the promotion zone will take more time and effort. In general, the larger board means long-range pieces have even more power than in Chu, so advancing pieces with a long-range promotion will be very helpful in the later stages of your attack. For this reason you want to ensure that your pieces with strong promotions can promote safely, so take the time to secure space at the edge of the promotion zone before dashing forward to upgrade your forces. As in Chu, some pieces with strong promotions should be held back until the endgame starts — namely the Gold General, Phoenix, Kirin and Drunk Elephant. The Golds and the Drunk Elephant are very useful defensive pieces, so don’t promote them unless they have a clear path toward the promotion zone and your King is otherwise secured. The Phoenix and Kirin promote to the strongest pieces in the game, so keep them back behind your front line until the board opens up; even then, keep them protected as much as possible as they head for promotion, as their movements are rather slow and awkward. As in Chu, a promoted Vertical Mover is a powerful addition to your attack.
Keep your Lion centralised and patrolling: This general principle from Chu is still fairly useful here, but as you can see from the sample openings above, the larger board area does permit some different Lion adventures at times. The challenge with the Lion in Dai is to maximise its impact in the opening, where it is safer from long-range attack due to the interposing pawns on both sides, and in the endgame, where a Lion assault on the King is often decisive. In the heat of the late middlegame, where pieces are dropping like flies and numerous lines of attack are opening up, make sure to keep your Lion safe from sniping attacks from long-range pieces. Do not be afraid to drop the Lion back to safety temporarily; better to keep the Lion alive deep into the endgame than to valiantly sacrifice it for early material gains. You will be glad you protected your Lion as you enter the endgame, particularly if a spicy mutual-checkmating-attack situation develops.
Don’t forget about defence! A useful principle to keep in mind in Dai as well as Chu — or in fact in any Chess-type game, where defence is less glamorous than attack and is all too easily neglected. As in Chu, your Rooks and Side-Movers are extremely useful for defence; R. Wayne Schittberger recommends dropping your Rooks back to the third rank to patrol in front of the King’s castle. Side-Movers can be placed on the fourth and fifth ranks to mount a solid defence against the enemy Lion. Keeping short-range pieces in defence of your edge pieces — the Lance and Reverse Chariot — can be useful too, in order to prevent an exchange along the edge opening a pathway to promotion for your opponent.

The Endgame

The basic principles of the endgame in Dai are very similar to Chu: advance your Golds and Drunk Elephant when it is safe to do so; advance your Lion toward the enemy King; and promote your forces when possible to make your attacking army more dangerous. The major addition in Dai are the new short-range pieces, in particular those with unusual moves that may not benefit from a promotion.

The puzzles below illustrate the powers of these new pieces in a checkmating attack. The Violent Oxen and Flying Dragons can be useful here, in that their slightly longer range can help restrict the movement of the enemy King. These puzzles are the only Dai-Shogi-specific tsumeshogi I’ve managed to find to date, and they didn’t come with solutions; I’ve dug these out of my archives and diagrammed the solutions so you can check your answers. I’ll present the four puzzles below, and solutions will come after my concluding section:

: Puzzle 1. Hint: remember the promotion rules.

: Puzzle 2. Hint: the Knight leaps into action.

: Puzzle 3. Hint: the Stone General is the foundation of your attack.

: Puzzle 4. Hint: the Violent Ox lives up to its name.

Final thoughts

Dai Shogi occupies a somewhat unfortunate position in the Shogi variant world; Dai has a little brother that’s extremely highly regarded, and larger siblings with very unique pieces and patterns of play. That leaves Dai somewhat at sea, being a larger version of Chu but without the craziness of other large variants like Tenjiku Shogi or Dai Dai Shogi.

However, I hope this article conveys the attractions that Dai Shogi can offer, and shows that it’s more than just Chu’s bigger, slower predecessor. Dai is a highly strategic game with a dynamic opening phase, and while the new pieces are of the weaker variety, they do have some unique characteristics that can come into play. Dai Shogi is also a great stepping-stone toward the aforementioned larger, crazier variants, given that it shares their size and strategic richness but is much easier to learn.

If you want to play Dai Shogi online, your options are unfortunately rather limited — you can play via PBEM on Richard’s PBEM Server (Dai Shogi is a sub-option of Chu Shogi). You can also play via this Japanese site, although you’ll need to have Flash enabled (my 568-move game above was played there).

For real-life play, your best option is to purchase physical sets with plastic pieces and sturdy vinyl boards from Angela Hodges. Real wooden Dai Shogi boards are still available in Japan, although the prices are significant, and wooden pieces are even more expensive; both the pieces and boards tend to be rare, so if you’re keen then I suggest buying them as soon as you see them in stock. The Go and Shogi store I linked there is very accustomed to international orders, and the proprietor speaks English well, so I can easily recommend them if you fancy a traditional wooden set.

Now that we’ve covered essentially all the basics of Dai Shogi in this post, my next Dai Shogi post will be an annotated game. The game in question is, unsurprisingly, very long, so this post will take some time to prepare. In the meantime, I will focus on presenting an annotated Chu Shogi game and will start my introduction to Tenjiku Shogi.

Tsumeshogi Solutions

Puzzle 1 Solution

The first puzzle may take a few tries to get; there are actually quite a few options for the first move, but only the Kirin sacrifice ensures the King cannot escape to the left and delay the mate. Remembering that the Dragon Horse is still able to promote in this position helps to find the pathway to the solution. In the end, the combination of the powerful Horned Falcon and the lowly Stone General is enough to secure the win.

Puzzle 2 Solution

The second puzzle provides a moment for the Knight to shine. Again the promotion rules are paramount here; the Reverse Chariot and Lance are both just outside the zone, so giving double-check with the Knight forces the King into position to be trapped by their promoted forms. The Violent Ox serves to box the King in and protect the Knight from capture.

Puzzle 3 Solution

Puzzle 3 is a bit more of a challenge; there are a number of blind alleys one can wander down before discovering the most forcing line. The solution makes clever use of the Stone Generals to pull the King out of the corner and restrict his escape squares. The final mate is a deadly combination of Dragon King and Stone General.

Puzzle 4 Solution

The final puzzle has a 9-move solution, which seems intimidatingly long, but in actuality the solution is pretty straightforward (both literally and figuratively). The key to this one lies in recognising the Vertical Mover’s dominance of the 2-file; with that file locked down, the Violent Ox can use its 2-square range to simply push the King back until the Side Mover must take the Ox, and then the Bishop’s diagonal is unblocked, allowing the mate.

Tagged Dai Shogi, Games, Shogi, Shogi Variants

Apr 09 2020

2 Comments

Games, Shogi

Chu Shogi, Part II: Attack and Defence

“Despite this complexity, after playing [Chu Shogi] a few times, one begins to feel that each piece has its own personality, and that not one of the pieces could have been left out without harming the character and charm of the game. A game as large as Chu could easily have been dull and ponderous; instead, it is rich in tactics, deep in strategy, and exciting to play.”

–R. Wayne Schmittberger, Shogi Magazine, October 1986

Following on from my previous article on Chu Shogi, this time I’d like to get into a bit more detail about attack and defence strategies. My main vehicle for this will be a discussion of building defensive castles, then attacking and utilising your pieces’ strengths, and finally some instructive checkmate puzzles (tsumeshogi) that demonstrate the powers of the unique Chu Shogi pieces in the endgame.

Before we get started, two quick clarifications:

Notation: in the diagrams below I’ll be using Western-style notation, as described on the Wikipedia page. This system is pretty easy to understand — Chess players please note, however, that a ‘+’ at the end of a move means the piece was promoted, not that it gave check. Also I’m used to Japanese notation, so I may not get it right all the time — if I make any mistakes, please shout and I’ll fix them.
Move numbering: Most Western sources use Chess-style move counting, where each numbered ‘move’ is actually a move pair, one from Black and one from White. I find this confusing when dealing with tsumeshogi puzzles, so I’m sticking with Shogi/Go-style move counting, where a move is simply a move from one player.

Building Castles in Chu Shogi

For us Chess players, building defensive structures for the King is made substantially easier by the presence of the castling move, which enables us to tuck the King safely behind one of the Rooks in a single stroke. For Shogi players, castling is not a move, but a process; players spend quite a few moves re-arranging their pieces to build fortresses around their King. Often these castles require substantial material investment and cover quite a bit of board space; Shogi castles need to be solid, given that the ability to drop captured pieces anywhere means that deadly attacks can occur very suddenly.

Chu Shogi of course is closer to the latter than the former — there is no specific castling move, and instead players must construct castles themselves. In Chu Shogi there are no drops, but the Lion Power pieces do present significant dangers; they can deliver mate even when pieces block their direct path to the King!

Below are some example castle formations that you may encounter in a Chu Shogi game:

Diagram 1: Chu Shogi castle formations

The Basic Castle is very commonly seen in Chu Shogi games, and is easily built: simply bring the Drunk Elephant in front of the King, flank it with your Blind Tigers, and keep your Gold Generals on either side of the King. The Golds are somewhat better placed one square out from the King, as in the centre of the top row in Diagram 1. The Basic Castle may be basic, but when combined with Side-Movers parked on the 3rd and 4th ranks and some patrolling Rooks as well, this formation can provide a decent amount of safety.

However, this castle has some weak points that become apparent if an attacking Lion breaks through and has the support of a long-range piece. The long-range piece pins the Drunk Elephant to the King, preventing it from capturing the attacking Lion (since that would expose the King to immediate capture):

chu-shogi-enhanced-castle-explanation-01

Diagram 2: weak points in the Basic Castle.

The immobile Drunk Elephant can’t defend the two red points in the blind spots of the Blind Tigers, so these squares become convenient places for the Lion to give immediate checkmate. The Enhanced Basic Castle, developed by Colin Adams, reduces this problem to only one weak square by swapping the Drunk Elephant and the right-side Blind Tiger. The Enhanced Basic Castle takes an additional move to build, but reducing these key weaknesses by half seems like a reasonable return on that tempo investment.

The bottom-left of Diagram 1 shows the Hanshin Tigers castle, which is also fairly easily formed but requires a greater material investment than the Basic or Enhanced Basic. In this formation, once the Phoenix and Kirin move away, the Blind Tigers are brought together in their place, allowing the Tigers to cover one another’s blind spots. Both Dragon Horses are then brought down over the Golds and backed up by the Silver Generals. A variant of the Hanshin Tigers moves the Silvers up over the Golds instead of the Horses. Either version creates a strong protective barrier, but requires keeping the Dragon Horses or Silvers locked down in defence of the King:

Diagram 3: Hanshin Tigers variations.

This castle comes recommended by the old Lucky Dog Games website. They give as a sample opening sequence for the Hanshin Tigers with Silvers as 1. Ln-6h 2. P-8h 3. P-5h 4. P-7h 5. Ky-7i 6. Ph-8i 7. BT-7k 8. BT5k-6k 9. S-8k 10. S-5k; a similar sequence would work for the Dragon Horse version, just leave the Silvers in place and shift the Dragon Horses one space inward instead.

In the bottom-centre of Diagram 1 you can find the Anaguma Castle. This castle is inspired by the Anaguma Castle of modern Shogi; the name means ‘Bear in the hole’ and it has a reputation as a very strong castle. The Chu Shogi version is certainly strong against frontal attacks, but requires a large material commitment, just like the modern Shogi version. The Anaguma also has the side effect of shifting your King closer to the left side of the board and reducing potential avenues for flight if the castle should collapse. On the positive side, the Anaguma does not tie down your Dragon Kings, which can then join your Free King to contribute to attacks elsewhere on the board.

Finally, in the bottom-right of Diagram 1 we have the Two Dragons formation. In this castle the two Dragon Kings occupy the spaces left by the Kirin and Phoenix once they are moved away. The placement of the Dragon Kings is ideal to support an attack in the centre. Since the powerful long-range pieces tend to be held back in early- and middlegame positions anyway, placing them in the centre of the castle is relatively convenient. However, committing early on to an attack in the centre can be risky — that can leave the wings more open to counter-attack from the opponent. In any case, this particular castle apparently was popular during the Edo Period in Japan, so it may be worth having in your arsenal. If you want to see a historical example of this castle in action, do check out this famous game between Mori and Fukui.

So, what castle should you use? There’s no single answer to this, I think — as in modern Shogi, your choice of defence will depend on the board situation and your own particular style. In a fast-moving, attacking game, the quicker castles like the Basic may be appropriate; whereas in slower, positional games, you may be want to take time to set up a robust defence. In any case, I’d recommend going through Chu Shogi games on Richard’s PBEM Server and observing how strong players adapt their defences to different board situations.

Attacking Principles in the Middlegame

As described in Part I, Chu Shogi is a fundamentally strategic game. The size of the board and of each player’s army means that precise forward calculation of tactical variations is often not practical; instead, aiming for good strategic positions and solid arrangements of your pieces is more important. Generally you will find it very difficult to imagine where your opponent’s piece may end up in 50 moves by just looking ahead move by move, as there are simply too many possible moves on each turn; but if you have a sense for what type of offensive or defensive shape he is going for, then you will be able to place your pieces properly to cope with that.

After the opening, the Chu Shogi board will have some clearly defined battle fronts where each player is attempting to make gains. Each side will have advanced phalanxes of short-range pieces to protect their pawn lines, with long-range pieces on the back ranks providing further support. The Lions will often be placed high in the centre of the board, both sides searching for opportunities to start a Lion invasion of the other’s camp. Both sides will aim to push their attack forward on one of the flanks, cramping their opponent’s defences, and cascades of piece exchanges may happen as one or both sides start attacking.

While going through my collected Chu Shogi materials I found this interesting exemplar early-middlegame position from Shogi Magazine:

Diagram 4: target middlegame position.

This position is by no means meant to be prescriptive — your positions should be constructed in accordance with what the game requires, not any specific target — but it can be useful to look at the key features of this position and why elements of it may be desirable.

First of all, in the diagram we can see that a Basic Castle has been built, albeit in this case with the Phoenix next to the King. The King is flanked by the two Golds, and ready to defend to the front are his Blind Tigers, Drunk Elephant, and Dragon Horses. The Lion is placed high and centrally, in front of the pawn line. Note that every single short-range piece on the back rank has been brought straight to the front lines, backing up the advancing Pawns. The 4th rank is defended by two Side-Movers, and the 3rd by two Rooks. On both flanks we have lined up long-range pieces, backing up the generals on the front line. Note that the Free King, the second-strongest piece on the board, is tucked away safely on 2L; just like the Queen in Chess, it doesn’t pay to bring your Free King out too early!

Now, I’ve no doubt that some choices made in this position would not stand up to current Chu Shogi theory, but nonetheless I believe it’s an instructive example. Leaving aside the specifics, we should be aiming for similar cohesion in our own games and applying appropriate core principles as we aim for a robust post-opening posture:

Bring the King to safety
Keep the Lion centrally placed, restricting the opponent’s Lion and looking for opportunities to invade
Bring the Free King to a safe spot on or near the back ranks
Advance most or all of your short-range generals to the pawn line to press an attack
Use long-range orthogonally-moving pieces to defend the 3rd and 4th ranks — Side-Movers and Rooks are good choices
Position your long-range attacking pieces to defend the advancing generals and Pawns, and drive out the enemy Lion if it attempts to invade

Keeping these principles in mind can help you navigate the opening and develop an early middlegame position that sees you ready to launch a coordinated attack. As you gain experience you will develop a greater sense for the positional requirements of each game situation, and you will get more comfortable experimenting with these principles and finding strategic setups that fit your personal style of attack and defence.

Tips for Specific Pieces

Chu Shogi has a diverse range of pieces at the players’ disposal, and each of them has a role to play in the battles to come. Here are some tips on how to put your soldiers to good use, gathered together from my archive of Chu Shogi materials.

The King: Often the King will stay in the centre of the back rank for most of the game. Try to set up a castle around him and cover the 3rd and 4th ranks to prevent the Lion getting too close too early. If you and your opponent are locked in a mutual mating attack situation, then it can pay to retreat your King toward a safer side of the board, but think carefully about when to spend your moves on a retreat; sometimes the best option is to regain the initiative and counterattack instead.
Pawns/Go-Betweens: In a game with so many powerhouse pieces, it’s easy to forget about the lowly Pawns and Go-Betweens. But both these pieces are essential to Chu Shogi play, and they should never be advanced thoughtlessly. A strong Pawn line backed up by short-range pieces provides an essential barrier against the opposing Lion, and letting your opponent break down that wall could be fatal. As the game develops and you continue to gain space, your Pawns and Go-Betweens can promote as well, so it’s worth carrying Pawns forward with you as you advance.
Phoenix/Kirin: These two pieces have the strongest promotions in the game (Phoenix promotes to Free King, Kirin promotes to Lion), so don’t advance them too early. In the endgame these pieces may have space to advance and promote, so until then keep them well back from the action.
Gold Generals: These pieces have the strongest promotion of any of the Generals (they promote to Rook), so they’re best kept away from the action to leave open that option in the endgame. They’re excellent on defence as part of your castle; in unpromoted form they cover very useful squares in your defensive formation. When the game opens up they can then be advanced if needed to bolster your attacking forces.
Silver Generals: The Silvers are useful attacking pieces, as in Shogi, but in a pinch they work well as defensive pieces too; as you saw above, some castle formations use Silvers to defend the King. Optimal placement and use of the Silvers may depend on what defensive formation you choose to adopt.
Ferocious Leopards/Copper Generals: These pieces should be on the front lines, backing up your Pawns. When advancing your Pawns and attempting to gain space, try to build up numerical superiority with short-range pieces like these. Above all, be patient — hold back on launching an attack until all your short-range generals are in place behind the pawns, and you know you’ll be able to continue pressing your attack even after your opponent starts exchanging pieces to slow you down.
Lances/Reverse Chariots: These pieces can’t move off their file anyway, so I advise keeping it simple: leave them in place defending their edge of the board! Opportunities may arise to promote them in the endgame, but for the most part these pieces tend to stay fairly static unless defending or attacking along the edge of the board, or if promotion opportunities open up later in the game.
Side-Movers: I’ve said this a few times already, so probably you got the message, but the Side-Movers are very important defensive pieces and should generally be patrolling your own 3rd and 4th ranks. An invading Lion is extremely dangerous and with even one supporting piece can probably demolish your castle, but Lions can only step twice on a turn — so with your Side-Movers covering two ranks, your opponent will need to work harder to approach your King with their Lion.
Vertical Movers: These pieces can sit together with your Dragon Kings and other long-range pieces, providing support to your front-line attackers and standing ready to harass the enemy Lion away should it be necessary. Once you gain sufficient space on one side or the other, try to promote your Vertical Mover to a Flying Ox. The Flying Ox is a strong attacking piece and will be a valuable addition to your forces once the board opens up.
Drunk Elephants/Tigers: These are paired together because they are prime defensive pieces — they both can cover 7 of 8 adjacent squares. Blind Tigers are easily moved into a Basic Castle early in the game, and they are very awkward to advance anyway due to being unable to move directly forward, so keeping them on defence is usually the best role for them. The Drunk Elephant should also be kept back to hold the line, but they serve a valuable extra purpose in the endgame. If enough lines open up for the Drunk Elephant to potentially promote, and you’re deep into the endgame, its potential to become a Crown Prince can be very useful. If you do get a Crown Prince, this is insurance against checkmate; even if your opponent succeeds in preventing the promotion, they will have spent valuable time doing so.
Rooks: Along with the Side-Movers, Rooks are key allies in the defence of your King. They can patrol the 3rd and 4th ranks very well, so try to keep these ranks clear so they can readily switch sides depending on your offensive and defensive requirements. As in Chess and Shogi, Rooks can play a valuable attacking role in the endgame, too.
Bishops: The Bishop, like your other long-range pieces, works well sniping from the back of your position and harassing the enemy Lion. Their diagonal movement can often provide opportunities for sneaky discovered attacks — where a move of another piece opens up a line from the Bishop to an opposing piece. On such a large board these opportunities can be easy to miss, so try not to forget your Bishops!
Dragon Horses/Dragon Kings: These pieces are strong ranged attackers, and can work well backing up your attacking generals on the front lines from the safety of the back ranks. As we saw above, both pieces can also strengthen your castle defences if needed or help prosecute a central offensive. In general, don’t be tempted to sacrifice these pieces for short-term positional or material gains — better to build a solid, well-supported attack, winning them the space to eventually promote and become very powerful Soaring Eagles and Horned Falcons. As attractive as those promotions are, don’t rush it; once the board thins out later in the game these pieces can dash across the board and promote pretty easily, and often safely. Rushing them to promotion may just give your opponent chances to gain tempo by harassing them with their long-range pieces.
The Free King: This piece is extremely strong, second only to the mighty Lion. In the early game, keep it far away from the front — a tactical mistake leading to a captured Free King would leave you at a huge disadvantage! Your opponent can also take advantage of a poorly-placed Free King and harass it from range, forcing you to retreat it and lose tempi. In the endgame, let the Free King run wild — its very high mobility is a valuable asset when harrying the enemy King.
The Lion: Your Lion is the most important piece in your army other than the King, but its unique capabilities mean it doesn’t need to hide away in the early game like the Free King. Most players advance the Lion over the Pawns very early in the game, attempting to stake a claim to the centre and probe for weaknesses in the enemy lines. Middlegame Lion invasions are a major feature of Chu Shogi, but don’t be tempted to attempt one too early; without backup your Lion could be easily driven back by your opponent’s long-range pieces, or even forced into a dangerous position if you haven’t opened up enough lines for it. Be aware too that the Lion loses some of its power as the board opens up, since then the opponent has an easier time targeting it with long-range pieces.
In the endgame, the Lion is absolutely devastating. Your goal here should be to advance your Lion as close to the enemy King as possible. To achieve this, bring forward your short-range pieces to interfere with or exchange off your opponent’s defending Side-Movers and Rooks; this will enable your Lion to break through. In combination with long-range pieces pinning down your opponent’s defensive line, Lions can create some spectacular checkmate opportunities once they get in range of the enemy castle. When paired with even a single short-range piece, the Lion can work methodically with it to compromise the enemy’s defenses. If need be, don’t be afraid to sacrifice powerful pieces to force your opponent’s King into the open — in those situations the Lion is often able to achieve a brutal checkmate all on its own!

The Endgame

The endgame is characterised by a much more open board, and this is often where the remaining long-range pieces become very important attacking pieces. Your long-range pieces held in the back ranks can dash forward and promote, and the Lions must advance a bit more carefully given their limited range and susceptibility to attacks from a distance.

To help simplify matters in this stage of the game, look for opportunities to exchange off long-range pieces if you have material superiority. A clever opponent can still mount a stout defence against greater numbers if they have some nimble long-range pieces roaming about the board, so exchanging them off the board so you have the only remaining long-range pieces can be much better for you. Meanwhile, be sure to promote whatever unpromoted pieces you have remaining, assuming you can do so safely, and if you have a Drunk Elephant in a position to become a Prince, try and do so. That leaves you with an extra royal piece which will force your opponent to split their attention.

Remember that Chu Shogi’s endgame is by nature very different from Chess and Shogi, so in certain situations you’ll need to be mindful of some of the special rules of Chu:

No stalemate: In Chess, stalemate — where a King is not in check but has no legal moves — is a draw. In Chu, stalemate is a loss, as there’s no prohibition on moving into check — so the weaker side must do so eventually, and hence loses.
No perpetual check: Repetition is illegal in Chu Shogi, so escaping from a losing situation via perpetual check is impossible.
Bare King loses: Under the Chu Shogi Renmei rules, as soon as one side loses all pieces besides the King or Crown Prince, they lose the game. Often this won’t happen as the losing side will resign first anyway, but in certain situations you may want to take this into account when planning your approach to an endgame with only a few pieces left on the board.

In addition to these differences in rules, Chu Shogi’s unique pieces add many interesting tactical possibilities to the endgame. The super-powered Lion and the late-game appearance of the other Lion Power pieces create some exciting possibilities for pretty checkmates. Probably the best way to get to grips with these possibilities is to try solving some tsumeshogi.

Tsumeshogi

Tsumeshogi are Shogi checkmate puzzles, and are perhaps my favourite Shogi-related activity. I’ve gone to a lot of effort in recent years to acquire tsumeshogi books from Japan, and I never cease to be amazed at the level of artistry in some of these puzzles. Chu Shogi has tsumeshogi too, although of course there aren’t nearly so many of them compared to modern Shogi. Having said that, there are some excellent ones to be found on the Japanese web, including historical 17th-century puzzles from Chu Shogi Renmei available here and here, or some modern creations here.

In this section I’ve picked out a few puzzles that illustrate some of the interesting endgame situations that can occur with Chu Shogi’s unique pieces. As with modern Shogi, solving puzzles like this is hugely helpful for your endgame attack technique, and for increasing your accuracy. The more tsumeshogi you solve, the quicker you’ll be able to spot strong continuations in your own endgames.

Before we start, I’ll summarise the rules of tsumeshogi:

The solver is always Black (moving up the board), and always has the first move.
Black’s King is not on the board in normal tsumeshogi; it’s assumed that Black’s King is going to be mated on the next move if the opponent gets a chance to counterattack.
Due to the above, every move from Black in a tsumeshogi must be check (a forcing move attacking the enemy King).
After each check, White must make the move that most prolongs the mate.
Some tsumeshogi are sou-gyoku tsumeshogi: two-king puzzles, where Black’s King is on the board and gets involved in the mate.
Hisshi tsumeshogi problems have at least one move that is not check.
A well-constructed tsumeshogi problem should have only one solution.

Tsumeshogi for the modern 9×9 game have additional rules relating to pieces in hand and drops, but that’s obviously not relevant here; I do love these kinds of puzzles a great deal, so at some point I’ll try to do a post about the many awesome varieties of tsumeshogi puzzles available for Shogi fans.

Now, below are several Chu tsumeshogi, each more difficult than the last. Try to find the solution by visualising the moves in your head, as you would during a game. Remember that all your moves must be checks (no hisshi puzzles here), and White’s response will always be the reply that keeps them alive the longest. I’ll also put a hint for each puzzle in the caption. The solutions will appear at the bottom of this article.

Hint: Black has both a King and a Prince — use them!

Hint: Free King takes one for the team.

Hint: Find a way to free the Falcon.

Hint: The ultimate sacrifice.

An interesting quirk in the Lion-trading rules

Now, while you’re mulling those problems over, I want to share with you something I discovered while picking which problems to diagram for this post. While searching through shorter problems for an introductory example, I found this puzzle:

At first glance this is a fairly simple three-move puzzle, but the solution turns out to be rather confusing. You can see the solution below; do you notice anything strange about the solution?

The final position has Black’s Lion protected by a Pawn. In theory, at least according to the Lion-trading rules on English Wikipedia, this is not checkmate — White’s Lion can legally take the Pawn, then the Black Lion, and then there’s no longer a threat to the King! But that being the case, why does this Japanese site present this as a correct tsumeshogi?

As it turns out, this specific situation — a non-adjacent Lion protected by a Pawn or a Go-Between alone — is covered by an addition to the Lion-trading rules adopted by Chu Shogi Renmei in 2004. They received a question asking whether the Lion’s double-capture in this situation should be viewed here as a single action, in which case the Pawn cannot be taken, because when viewing the board state as a whole the Lion is both non-adjacent and protected. Alternatively the double-capture could be seen as two separate actions, in which case the Lion can take the Pawn first, then the Lion is adjacent and can be taken freely.

Ultimately, Chu Shogi Renmei adopted the single-move interpretation, meaning that the above puzzle does have a checkmate. The Lion cannot be taken, because it is considered to be protected by the Pawn even though the Pawn could be taken and the Lion would have no further protection afterward.

The reasoning behind this, as I understand it, is that in certain situations ruling the Lion’s double-capture as a double move can lead to contradictions in the trading rules. Let’s use the same puzzle, but just shift the Bishop slightly so it protects the Lion:

So under the two-move interpretation, in this situation White effectively ends up trading away their Lion and only nets a Pawn, which is exactly the sort of thing the trading rules are supposed to prevent. As a consequence Chu Shogi Renmei ruled that we should view the Lion’s proposed double-capture as a single move, so that effectively when the Lion is taken the Pawn is still in place, threatening recapture. That in turn means the double-capture cannot be made, and so in the original puzzle, we do have a checkmate.

At first this seems complicated, but in practical terms it’s just reinforcing the aim of the Lion-trading rules, and ensuring that there are no situations where trading off the Lion for only a Pawn in compensation is allowed. A Lion may still take a Lion one space away protected by a different piece, by taking the protecting piece and then the Lion on the same turn — the protecting piece just cannot be a Pawn or a Go-Between. If you can read Japanese, you can see Chu Shogi Renmei’s discussion of this precise situation here (see Case 4 on that page).

Having learned all this, I felt that using a problem relying on a very specific rules quirk as an introductory puzzle would be far too confusing, and selected the other three-move problem above instead.

Tsumeshogi Solutions

Now then, hopefully you’ve set some time aside and worked out the solutions to the four tsumeshogi above? If so, well done! If not, we’ll go through the solutions so you can see where you went wrong. First, the three-move puzzle:

Since Black has a Crown Prince as well as a King, the King can finish off the other King personally! I was very pleased with this as an introductory Chu puzzle, since the solution highlights the unusual consequences of having an extra King, which is a very new concept if you are more accustomed to modern Shogi or Chess.

Now the five-move puzzle:

Here we have a lovely example of a Lion checkmate, enabled by the valiant sacrifice of the Free King. As mentioned in the endgame section above, sacrificing material to bring the King in range of the Lion often pays off — the Lion can very frequently chase down the enemy King and give mate on its own.

Next, the nine-mover:

For one of the puzzles I wanted to showcase a different Lion Power piece, and in this puzzle we get an instructive example of how the Horned Falcon can very effectively trap the enemy King even in a seemingly well-defended corner. The Falcon’s forward Lion Power allows it to jump or double-capture its way to the King, and conveniently it can also cover both potential escape squares. The setup is nice too — once we figure out that the Horned Falcon can deliver mate in the corner, opening the line to the King for the Whale pops out as an elegant way to drive the King toward his doom.

This puzzle also reinforces a very useful rule of thumb for tsumeshogi — every piece on the board is there for a reason! If a problem could be remade without a given piece and not change the solution, then it’s not a well-constructed problem. So when you’re stuck for a solution, have a think about what every single piece is doing on the board, and see if that shakes loose any clues.

Finally, the mammoth eleven-mover:

Yes, it’s another problem playing with Chu Shogi’s multiple royal pieces, but this one was too good to pass up. Sacrificing a King is an outrageous way to start a checkmating combination! I feel the puzzle would be even a bit more impactful if the King sacrifice came directly before the checkmating move, but even so it’s a fairly jaw-dropping thing to see for a Chess or Shogi player.

From here, I’d suggest checking out the other tsumeshogi I linked earlier, and try some of the other audacious puzzles available to test your Chu instincts to the limit. Solving puzzles like this is a huge help to one’s endgame technique, generally speaking, and some of these puzzles are very cleverly made artistic works, as well. If you eventually become able to solve the really long puzzles lasting a hundred moves or more, you’re well on your way to being an extremely strong Chu player. The real test, however, is whether you can solve the infamous Skyscraper, the longest tsumeshogi ever created, which lasts a staggering 3,257 moves.

For those who can’t read Japanese: you can view the solution to any of the puzzles on the linked sites by selecting it from the drop-down menu on the puzzle’s page, then scroll through the moves using the buttons underneath. There are two rows of buttons; the second row of six is the one you need to use. Going from left to right, the buttons are [Go to first move][Go back ten moves][Go back one move][Go forward one move][Go forward ten moves][Go to last move].

The final installment

The third and final part of my Chu Shogi coverage — for now, at least — will be an annotated Chu Shogi game. I will be presenting a game from the Chu Shogi Renmei website that, to my knowledge, has not been analysed in English before. I’m by no means a master of Chu Shogi, but I know enough to explain the basic ideas behind key moves in the game, so hopefully that will give you a clearer sense of how to evaluate positions in Chu Shogi and how a typical game might flow.

Also, in the near future I’ll be covering Chu Shogi’s big brother: Dai Shogi. My materials for the Dai Shogi introductory article are already almost finished, so this may get posted before the Chu Shogi game. Either way, I hope you’re enjoying my Shogi variant coverage — please do post comments below or send me an email if you have any feedback, corrections, or suggestions.

Tagged Chu Shogi, Games, Shogi Variants, Tsumeshogi

Apr 05 2020

14 Comments

Games, Shogi

Chu Shogi, Part I: How to Play

As some of you out there already know, I’m a huge fan of Shogi, the Japanese version of Chess, and its many variants. Shogi is a dynamic, attacking game enjoyed by millions of players around the world, and in my view is the most exciting of the major Chess variants played today. Chu Shogi is my favourite of the many larger variants of Shogi, and in my estimation is the best-designed game of the lot. I hope that by the end of this very long post you might be inspired to give this unique and fascinating game a try.

I have to admit that, as much as I love Chu Shogi, it is substantially more difficult to learn than modern Shogi or Chess. The board is large — 144 squares, as compared to 64 in Chess or 81 in modern Shogi — and each player starts with 46 pieces in their army. In Chess you need to learn the moves of six different types of pieces, whereas in Chu Shogi there are 28 different moves to remember!

However, once you get a game or two under your belt, all that complexity will melt away — you’ll be surprised how quickly the rules will become second nature. In this post I’m aiming to help you on that journey, by providing a complete reference to all the rules and piece movements you need to know to get started with this fantastic game.

I’ll start first with a brief look at the origins of the game, then I’ll describe the rules in detail, then I’ll show off the moves of all the pieces, and finally I’ll offer some basic tips for new players. Note that given the detailed kanji characters on the pieces and the complexity of some of the diagrams below, I’ve made this post so that each image links directly to a much larger version — please do click through to the larger images if any of the diagrams look a bit cramped on your device.

What is Chu Shogi?

Back in the 14th and 15th centuries, before modern Shogi existed, the Japanese were playing not just one, but three main variations of Shogi: Sho Shogi, Chu Shogi and Dai Shogi. These names mean, respectively, Small Shogi, Middle Shogi, and Large Shogi, and refer to the different board sizes used by each game: Sho Shogi is the direct predecessor to modern Shogi and is played on a 9×9 board; Chu Shogi uses a 12×12 board; and Dai Shogi is played on a 15×15 board. There were many other Shogi variants being developed in Japan around this time, but these three games were by far the most popular.

Chu Shogi is one of the most popular variants of Shogi played today, chiefly because of its finely balanced armies and the dominating presence of the Lion, a spectacularly powerful piece that shapes the entire game. A game of Chu Shogi is substantially more strategically and tactically complex than the smaller Chess-type games we’re used to, and offers the dedicated player limitless variety and challenge. Learning how to coordinate one’s army of 46 pieces on this large board can help us achieve greater strategic heights in our Shogi and Chess games, too.

Thanks to its fantastic play experience, Chu Shogi is the only ancient ancestor of modern Shogi that remains officially alive today. The Chu Shogi Renmei in Japan is the governing body for the game, and there are still regular tournaments happening. Here in the West, Chu Shogi has a small but die-hard following, and many Chu players consider it perhaps the best Chess-type game ever invented (I agree with this assessment). Nowadays Chu Shogi can be played online in real-time or correspondence forms, in domestic and international tournaments (albeit with only a few players), and solo against strong computer opponents. Chu Shogi is more accessible than ever, so why not give it a go?

The Origin of Chu Shogi

Chu Shogi’s immediate ancestor is Dai Shogi, which first appeared in the form of Heian Dai Shogi, a rather ponderous game played with 34 pieces per player on a 13×13 board. This game is first described in the diary of Fujiwara no Yoninaga, a high-ranking general, which was written between 1135 and 1155. Various other diaries throughout the 14th and 15th centuries make reference to Dai Shogi and present it as the most enjoyable form of Shogi, which suggests by this time it had reached its later form of a 15×15 game with 65 pieces per player (which is enormously better than Heian Dai Shogi).

The first reference I’ve found to a much larger form of Shogi comes in a mid-14th century text called Isei Teikin Orai. The book refers cryptically to a form of Shogi with 36 pieces on the board and a ‘dense’ form of Shogi with, apparently, 360 pieces. Unfortunately there are no further details in this book about this mysterious form of large Shogi, although perhaps it is a very early reference to some form of Tai Shogi with its 25×25 board and 354 pieces? Recent research by Professor Tomoyuku Takami proposes that, based on late Heian and Muromachi period documents, the first large Shogi may in fact have been Maka Dai Dai Shogi, which was then reduced in size to form the other large variants including Chu Shogi. More on this to come when I cover Maka Dai Dai Shogi in a future post.

The first detailed presentation of Chu Shogi’s board and rules comes in an Edo Period text titled Shōgi Rokushu no Zushiki (象棋六種之図式), which itself has a tangled history. The book was previously published by 16th-century Shogi craftsman Minase Kanenari as Shogi Zu (Illustrations of Shogi) in 1591, and he said it is a copy of a text he borrowed from a Kyoto Temple that originated in 1443. Allegedly that text is itself a copy of an even more ancient document, but we don’t know anything about that original source.

Below you can see scanned pages of the Shōgi Rokushu no Zushiki that show the Chu Shogi board, promoted pieces, and the movement powers of the pieces:

Thanks to this book we know that Chu Shogi existed in essentially its current form all the way back in 1443, and possibly significantly earlier. There are two other Edo-era sources, the Sho Shogi Zushiki and Shogi Zushiki from the late 17th century, which also describe the rules of Chu Shogi and numerous other variations of Shogi. In most cases they agree on the rules, but some of the very large games have some inconsistencies across these three volumes — more on that when I cover those games in future posts.

Regardless of some of the inconsistencies here and there, Shogi historians generally agree that Chu Shogi was a reduced form of Dai Shogi, which may have been the first large Shogi game or itself derived from larger games. Chu Shogi was then reduced further to Sho Shogi on the 9×9 board, and in the 16th century the drop rule was introduced, giving rise to the modern form of Shogi. Subsequently this rejuvenated version of Sho Shogi became by far the most popular form of the game. Prior to that, Dai Shogi was considered the most prestigious form of Shogi, followed by Chu Shogi, whereas Sho Shogi was thought to be a short and easy game more suitable for children (!).

After modern Shogi took over, Chu Shogi still remained mildly popular all the way into the 20th century. Unfortunately the game suffered a significant drop in popularity following World War II, and even strong support for Chu Shogi from some professional Shogi players failed to revive it to its former glory. In the 1970s and 1980s, an Englishman called George Hodges collaborated with Japanese Shogi scholars to bring Chu Shogi, Dai Shogi, and many other Shogi variants to Western audiences. George Hodges is largely responsible for popularising these games in the West, and he even produced physical sets for large Shogi variants all the way up to the gigantic Tai Shogi. Unfortunately George died in 2010, but his widow Angela Hodges continues producing his Shogi variant sets to this day.

The rules I’ll be presenting here are the rules used by the Japanese Chu Shogi Association, the Chu Shogi Renmei. While these differ in some respects from the rules generally used in the West, particularly in the promotion rules and King-baring rules, the textual evidence we have such as Chu Shogi checkmate puzzles indicates that the Chu Shogi Renmei rules are the same ones used in medieval Japan. For that reason I encourage you to use these rules, as they seem to be historically correct and also have less ambiguity in certain board situations.

The Rules

At the beginning of a Chu Shogi game, each player starts with 46 pieces of 21 different types. The initial board position looks like this:

Diagram 1: Chu Shogi initial position

Just for clarity, for the rest of this post I’ll refer to the two sides as Black and White — Black on the bottom of the board heading up, White at the top heading down. Note that some game records from a long time ago have Black at the top rather than the bottom, but this is always noted somewhere if that’s the case.

Winning the game

As in any Chess variant, the goal of Chu Shogi is to eliminate your opponent’s King. However, unlike Chess, in Chu Shogi you must capture the King, rather than checkmate it — and it’s possible to have two royal pieces at once in Chu Shogi, the King and a Crown Prince. If a player has both a King and a Crown Prince in their army, then the opposing player must capture both of those pieces in order to win.

The nature of Chu Shogi’s win condition means that there’s no stalemate as in Chess, and there’s no prohibition against moving a royal piece into check or checkmate. Obviously this is normally a pretty bad idea.

The Bare King Rule

The Chu Shogi Renmei adopts an additional rule where baring the enemy King is also a win; in other words, if you eliminate an opponent’s entire army except a King or Prince, then you win. However, if your opponent could on their next move bare your King as well, this is a draw, or if they could capture it on the next move, they win instead.

The rule further specifies that any endgame of King + some pieces versus a bare King is a win for the baring side, except when they only have a King + Pawn or King + Go-Between, in which case they have to promote the piece in question first in order to claim the win.

In practice the Bare King Rule isn’t hugely important, as most players would resign anyway as soon as the game seems hopeless, but nevertheless the rule has some interesting consequences for certain endgame situations.

Taking a turn

Once the game starts, Black moves first. The players alternate moving one piece on the board according to the specific movement powers of that piece. If that piece lands on a space occupied by an enemy piece, that piece is captured and permanently removed from the game (there are no modern-Shogi-style drops in Chu Shogi). Pieces cannot capture or move through friendly pieces. If a capture occurs then the move ends at that point — unless the capturing piece has ‘Lion Power’ (explained below), in which case a second capture can be performed. If the captured piece is the opponent’s last remaining royal piece (King or Prince), then the game ends immediately and the capturing player wins.

Normally a player must move a piece somewhere on their turn, but certain pieces with ‘Lion Power’ can ‘move’ without actually changing the board position — this means that player effectively passes their turn. This may be relevant in certain tight endgame situations where not moving can be preferable to moving.

Repeating positions

Sometimes during the course of play, players may enter into a cycle of repeating positions — for example, if a player is threatening their opponent’s King repeatedly with the same piece.

Chu Shogi Renmei’s rules have comprehensive guidelines for dealing with repeated positions:

If the board position is repeating due to one player repeatedly checking the opponent’s King or Prince (placing them under immediate threat of capture), then they must change their move before the 4th repetition of the same position or lose the game.
If one side is repeatedly attacking the opponent’s non-royal pieces during the repetitions, the attacking side must change their move before the 4th repetition of the same position or lose the game.
If the position is repeating due to both players passing using ‘Lion Power’ pieces, then the first player who passed must change their move before the 4th repetition of the same position or lose the game.
If the position is repeating and neither side is attacking, then a draw can be claimed.
In cases not covered specifically by the above rules, then whichever side causes the 4th repetition of a board position will lose the game.

Generally speaking, due to the lack of stalemate and perpetual check thanks to the above rules, draws are rather rare in Chu Shogi.

Promoting pieces

Both players have a promotion zone on the board that consists of the four end rows of the board from their perspective (the rows that contain the bulk of their opponent’s army at the start of the game). So, Black’s promotion zone is rows A through D in the above diagram, and White’s is rows I through L.

If a player advances one of their pieces into their promotion zone, they may choose to promote that piece by flipping it over; the other side will have different characters written in red that show the name of the promoted piece. Promoted pieces are more powerful than the starting version of the piece — often significantly more powerful. Once a piece is promoted, it remains promoted until the end of the game. Promotion happens for each piece only once.

Here’s the starting position of Chu Shogi with all the pieces flipped to show their promoted sides:

Diagram 2: Chu Shogi initial position with pieces flipped to their promoted sides

Note that three of the pieces still have black characters on them — these are the King, Lion and Free King, none of which can promote. I’ve left them in these diagrams just as a reminder of their position in the starting array.

When a piece moves into the promotion zone, promotion is optional — this may sound pointless, but there are situations where promotion may not be advantageous, at least not right away. Some pieces have promoted forms with very different movement abilities, so you may wish to defer promotion if you could make better use out of the original movement pattern.

If you want to promote the piece later after deferring when you first entered the promotion zone, you have to either A) move the piece out of the promotion zone, then re-enter the zone and promote on that move, or B) capture something in the promotion zone.

Note that some pieces that cannot move backward — Pawns and Lances — could theoretically get to the last row on the board and never be able to move again. If an unpromoted Pawn is about to reach the last rank, you can promote it even on a non-capturing move; if any other piece gets stuck unpromoted on the last rank, it just sits there unable to move until it gets captured.

NB: I’m using the Chu Shogi Renmei promotion rules here, which are more strict than the rules on Wikipedia or in the Middle Shogi Manual. In those rules, you can promote any piece after a non-capturing move when already within the promotion zone. However, this makes a lot of Chu Shogi board positions a bit more ambiguous and can cause some rules questions, so I recommend the Chu Shogi Renmei rules.

The Pieces

Remembering all the different moves of the Chu Shogi pieces is a bit challenging at first, but you’ll soon see that there’s a certain logic and pattern to them. The vast majority of pieces can move in a few directions one square at a time, or over any number of squares in some directions, or some combination of the two. A few pieces can jump over some squares, even if those squares contain friendly or enemy pieces. A few others have ‘Lion Power’ and effectively move twice in a turn; this is explained further below.

I’ve made some handy diagrams to illustrate the moves of all the pieces. The diagrams show you the pieces in a rough order, starting from the top row of your army down to the last row. Each piece’s promoted form is shown below its initial form. Remember that the King, Free King and Lion don’t promote.

In the diagrams below, orange squares indicate squares a piece can step to during a move; squares with stars indicate squares pieces can jump to, passing over intervening pieces; arrows indicate directions in which the piece can move an unlimited number of squares; and finally, exclamation marks indicate the piece can perform igui capture on that square (see ‘Lion Power’ below). As always, click each picture to see a massive huge version of the diagrams.

You’ll notice a certain pattern to the distribution of piece movements in the starting position. The back rank contains the King, the Drunk Elephant (both a strong defensive piece and capable of promoting into a royal Crown Prince), and a large crew of short-range Generals. The second and third ranks contain mostly longer-ranged pieces, with the most powerful pieces sitting in front of the King. The fourth rank consists of 12 Pawns, and finally in the fifth rank we have two Go-Betweens, the spearhead of our advancing army.

Note that to help you remember the piece names in full, I’ve used two-character pieces in the above diagrams, but for some subsequent diagrams (and in future Chu Shogi articles) I’ll mostly use abbreviated, one-character pieces to aid visibility. Here is a zoomed-in view of one player’s army with one-character pieces; the first diagram shows the starting position again, and the second has all the pieces flipped to show their promoted sides:

: The starting position for one player, with one-character pieces.

: The starting position with all pieces flipped to show their promoted sides.

For players of modern Shogi, you’ll see that that in general there are many more powerful pieces in Chu Shogi. In Shogi the most powerful pieces are the Dragon King and Dragon Horse; in Chu, you have two of each these on the board at the start of the game, and when they promote they become much more devastating. In Chu you also have the Free King, sometimes called the Queen, which moves as far as it likes in eight directions just like a Chess Queen (but Chu Shogi invented this piece 250 years earlier!). Finally you have the Lion, a piece so flexible, powerful and exciting to use that it inspired me to write a whole article about powerful pieces in Chess variants.

Print versions: I’ve also produced two single-page reference sheets for all the Chu Shogi moves, one version with 2-kanji pieces and another with 1-kanji pieces. The pieces are paired up with their promoted forms and again mostly follow the order of the diagrams below. Hopefully these will help you out if you bring a Chu Shogi set to a games night or your Chess or Shogi club.

: Chu Shogi reference sheet (2-kanji pieces)

Lion Power

To understand how strong the Lion is, you need to understand its special movement rules, referred to as ‘Lion Power’. As you can see in the diagram above, the Lion can jump over one square in any direction, bypassing any friendly or enemy piece on that square. However, it can also do something uniquely powerful — it can perform two single-square moves in any direction in a row, on one turn, and one or both of these moves may be a capture.

This has some interesting side effects — for one, the Lion may appear to capture an adjacent piece without moving, by moving to its square, capturing it, then moving back to its starting square. This is called igui — Japanese for ‘stationary eating’ — and in the diagrams above the squares where igui is possible are marked by exclamation marks in the Lion’s diagram. The Lion may also move to an adjacent empty square and then back, appearing not to move at all; this is how one may ‘pass’ their turn, as mentioned above. Finally, the Lion may capture two pieces in one move.

Here are a couple of examples of the Lion’s unique powers:

Diagram 3: Examples of ‘Lion Power’

As you can see, these powers make the Lion far more flexible and powerful than any other piece on the board. No enemy piece can sit adjacent to it, as it will just be instantly gobbled up igui-style. The Lion can easily escape threats by leaping away or by taking two nimble steps around interposing pieces. Finally, if an opponent leaves multiple pieces undefended, the Lion will eagerly devour them all. So, even without long-range movement abilities, the Lion dominates the board — and when you use it yourself, you’ll see how exciting the game becomes thanks to this magnificent beast.

Lion-trading rules

Chess players out there will be familiar with the Queen trade — when two players mutually agree to simplify the board position by exchanging Queens. In a Queen trade a player will offer their Queen for capture by the other Queen, with their pieces in position to immediately recapture the opposing Queen. The end result is both players lose their Queen but nothing else of consequence, leaving behind a less tactically complex and usually more boring game.

However, the wise inventors of Chu Shogi knew they had a hit on their hands with the Lion, and wanted to discourage players from trading them off to simplify the game. To achieve this they included several anti-trading rules that forbid players from capturing or re-capturing opposing Lions in certain situations. These rules ensure that the Lions often stay on the board for a long time during a typical Chu Shogi game, and that gives this remarkable piece a chance to truly shine.

I’ve created a few diagrams here that summarise the main points of the Lion-trading rules:

Diagram 4: Lion Trading Rules

These rules seem a bit complicated at first, but as you can see in the diagrams above, there’s really just a few points to remember:

A Lion can always capture an adjacent Lion.
A Lion may not capture a non-adjacent Lion protected by an enemy piece — this prevents a mutual Lion trade, where the Lions are off the board but the position doesn’t change much otherwise.
If a non-Lion piece captures a Lion, then the opponent can’t do the same thing on the next turn. This means that if your opponent has just taken your Lion with a non-Lion piece, you can’t take theirs right away, even if it’s unprotected! This prevents trades making use of non-Lion pieces.
A Lion can capture an opposing Lion protected by another piece, but only if it may capture another piece at the same time — and as long as that extra piece is not a Pawn or a Go-Between. This means that if both Lions are going off the board in this kind of position, the Lion that initiates the exchange has to take an additional piece of at least some value with them; again this discourages Lion trades, since trades won’t be possible on even terms.

There are some interesting tactical situations that can arise out of the Lion-trading rules, but don’t worry about those for now — when you’re just starting Chu Shogi, focus on simply exploring the Lion’s capabilities and getting used to these rules. In subsequent posts I’ll talk some more about these rules and how they impact Chu Shogi tactics.

Other pieces with Lion Power

Two other pieces in Chu Shogi have a limited form of Lion Power — the Horned Falcon and the Soaring Eagle. The Horned Falcon can use Lion Power only directly forward — so it may jump two squares forward, or make one or two forward steps, or make an igui capture or a double capture forward. The Soaring Eagle can do the same except on the two forward diagonals only.

The Lion-trading rules do not apply to the Horned Falcon or Soaring Eagle.

Note also that the Kirin (sometimes written Kylin in some Western sources) promotes to a Lion. Once the Kirin promotes to Lion, all Lion Power and Lion-trading rules now apply to that piece.

Beginner Chu Shogi Tips

Chu Shogi can seem daunting at first — just look at all those pieces! — but here I’ll give you a few key tips that can help direct your play in the first few games. I’ll write some additional Chu Shogi articles in the future, including detailed discussion of the opening, middlegame and endgame, and a fully-annotated game (this will take some time — the game I’ve chosen to annotate is 327 moves long!).

For now, here are some key tips for each stage of the game:

The opening

Chu Shogi games are long — expect a typical game to last about 300 moves (compared to an average Chess game at about 80 moves, or a modern Shogi game at about 120 moves). With that in mind, take your time in the opening — Chu Shogi games tend to build gradually, with each player re-arranging their pieces within their own ranks in preparation for launching a coordinated attack. Take your time, follow the tips below and you should be able to keep yourself out of trouble in the opening.

Don’t neglect your short-range pieces! Chu Shogi has a lot of powerful long-range pieces, so it’s easy to forget about your short-range pieces in the back ranks. However, if you advance these pieces early on, they serve a valuable role in protecting your front-line Pawns from an enemy Lion invasion. Later in the game you’ll also have a much easier time promoting these short-range pieces if you’ve already advanced them early, and many of the short-range pieces have useful promotions. Finally, a coordinated march of Generals on the enemy position can enable you to shift the enemy’s long-range pieces into disadvantageous positions, disrupting their attacks or even exposing them to capture.
Set up a solid defence around your King. Even with the many rows of pieces in front of your King, you still should spend extra effort to protect him right from the start of the game. In particular, keep the Drunk Elephant, Blind Tigers and Gold Generals close at hand — all three of these pieces can cover a lot of squares around your King. The Drunk Elephant becomes extra valuable if kept alive in the endgame, since it can promote to a Crown Prince and make your opponent have to capture two royals to win the game. Similarly, the Gold Generals promote to Rooks, which are extremely useful pieces to have around in the endgame when many other long-range pieces may have been swept off the board.
Use your Lion to claim the centre. Jumping the Lion over your Pawn line early on to cover the centre of the board is very useful — it deters the enemy Lion from making opportunistic attacks on your vulnerable Pawns, while threatening to do the same to them. If your opponent starts harassing your Lion with capturing threats, you can easily retreat it back over the Pawn line to safety. The Lion controls a lot of space and is very hard to pin down, so use that to your advantage!

The Middlegame

The middlegame of Chu Shogi starts once both players have developed their short-range pieces behind the Pawns, lined up strong long-range pieces behind them, and are starting to attack the enemy’s position, often along one of the flanks of the board. Succeeding in the middlegame requires strong strategic acumen — tactics are important, but there are so many possible moves on any given turn that it’s often very difficult to anticipate the opponent’s replies to each of your moves. Solid strategic principles can guide you better over the longer term.

Advance methodically. Concentrate your attacking forces along the side of the board where your opponent looks weakest. Back up Pawn advances with your short-range pieces, and keep long-range pieces behind them to snipe at any invading enemy Generals or to deter Lion incursions. Try to keep your pieces moving in lockstep — retreating weak pieces is slow and will lose you time, and time is a key resource in Chu Shogi.
Avoid pointless material losses. At this stage of the game, try to amass your forces on weak points in the enemy camp, allowing for a mass assault later on, rather than impatiently trying to punch through with just a few strong pieces. Early material losses can mount up, and sacrifices can fail to significantly damage your opponent’s defences given the size of each player’s army; whatever hole you’ve punched in the enemy lines with your powerful piece sacrifice will soon be plugged by another piece.
Don’t rush toward promotion. Your short-range pieces will take time to breach enemy lines and hit the promotion zone — don’t rush this, they serve a valuable role in the meantime defending your pawns and discouraging Lion invasions! Your long-range pieces can promote very easily once the board opens up after a few battles break out, so don’t fling them headlong into danger to seek promotion — soon enough you’ll be able to promote your long-range pieces essentially at will. Once you do start to make headway on the enemy position, try to make it a goal to promote a Vertical Mover to a Flying Ox — the Flying Ox is a strong attacking piece.
Keep your Lion centralised and patrolling. Keeping your Lion in the centre will help restrict your opponent’s advance to one flank or the other, and will keep their Lion contained. While managing your own advance, don’t forget to keep an eye out for the enemy Lion, and look for opportunities to drive it away temporarily; this can open up opportunities to make a dent with your short-range pieces, which can then open up lines for your Lion to do some serious damage. Your opponent will be looking to do the same, of course, so don’t let their advancing army set up a beachhead for their Lion!
Don’t forget about defence! While hunting the enemy King and/or Prince, don’t forget to maintain suitable defences around your King position. Many players keep their Side Movers on the third and fourth ranks — this sets up a two-rank barrier that even the Lion finds difficult to cross. Leaving a couple of Rooks behind those pieces provides a further deterrent for invading enemy forces.

The Endgame

The endgame of Chu Shogi is a much more open affair than the middlegame — both players’ defences have given way to some extent, and many pieces have been swept off the board. Long-range pieces are flitting dangerously around the more open board, many more pieces are able to promote safely, and victory might be in sight for one of the players.

Make use of your Gold Generals and Drunk Elephant. Gold Generals can now be advanced in the endgame, preparing to promote to much more dangerous Rooks. Your Drunk Elephant, if needed, can advance into the promotion zone to become a Crown Prince, giving you another bit of insurance in case your King comes under threat.
Advance your Lion on the enemy King. Your Lion is absolutely devastating in the endgame when backed up with some other pieces. Even if your opponent has created a strong defensive castle structure — to be covered in the next article — a few sacrificed pieces can open up holes in that structure that your Lion can exploit. In your hunger for victory, just be careful not to leave your Lion too exposed, or your opponent may harass it away or even capture it!
Take advantage of strong promotions. If you’ve managed to keep your Phoenix and Kirin alive, now’s the time to bring them forward! They move a bit awkwardly, but they promote to Free King and Lion, and having extras of those pieces is always extremely useful. You may also have Horned Falcons and Soaring Eagles or other strong pieces available through promotions, which can do severe damage to your opponent’s remaining defences.

With these basic tips in mind, you should be able to get a handle on the general flow of a Chu Shogi battle once you have a few games under your belt. There’s some good information out there online if you want to take your game further — get in touch with Angela Hodges to buy PDF copies of the Middle Shogi Manual and the back issues of Shogi Magazine, which contain a series of useful articles on the game by R. Wayne Schmittberger. Even if you can’t read Japanese, Google Translating the Chu Shogi Renmei website may be useful — there are a number of instructive articles there, as well as checkmate puzzles and complete game records for both historical and recent high-level matches.

Why should I play Chu Shogi?

You may have looked through this article and thought to yourself — why learn all this? Isn’t this game just a more complicated, slower version of Shogi? Why not just learn Shogi instead, a game with millions of players around the globe?

Ultimately, yes, it’s a complex game, and there’s quite a bit to learn at first. But Chu Shogi offers a very different experience from the typical Chess/Shogi game — whereas those games feel like very abstracted skirmishes between two squadrons of troops, Chu Shogi feels like a war. A strategic approach is vital, because right from the start you’ll be making very consequential decisions about where to concentrate your strength, where and when to attack, and how best to execute your devious plans. All the while, the Lions are stalking the board, scaring other pieces into submission, and offering new tactical situations you can’t find in any game of Chess or Shogi.

Even if you’re not a Chess or Shogi player, I recommend trying Chu Shogi at least once or twice — it’s an incredibly rich game, and could easily turn out to be your ‘lifestyle’ game. If you’re a Chess player, Chu Shogi will be like entering a totally different universe — the balance between tactics and strategy is massively shifted toward strategy, the board is filled with pieces that behave very differently from anything in Chess, and the board is so large that it feels like playing three games of Chess at once. If you’re a Go player — well, Go is hard, so you’ve already got a lot on your plate, but as a fan of a highly strategic game you may find Chu Shogi a particularly compelling take on the Chess genre.

Finally, for you Shogi players, I certainly recommend you keep playing Shogi, as it’s a fantastic game. But playing Chu Shogi can certainly pay dividends for your Shogi game, as well as being extremely good fun on its own terms. If you don’t believe me, then at least you should believe Oyama Yasuharu, legendary Shogi player and 15th Meijin, who was an outspoken advocate for Chu Shogi:

“Ever since I was small I have often played Chu Shogi. My cautious and tenacious Shogi style is probably due to the influence it has had. I believe the reason I think, above all, about improving the cohesion of my pieces, is that I have played Chu Shogi.”

Next steps

So, in closing, I hope this post encourages a few of you out there to give Chu Shogi a try. You can play in live games via the 81Dojo client linked on the Chu Shogi Renmei website, via PBEM on Richard’s PBEM Server or Game Courier, or with physical sets produced by Angela Hodges.

If you’d rather practice against AI opponents, you can play in your web browser via the Dagaz Project — scroll down to ‘Shogi Family’ and you’ll see Chu Shogi, Dai Shogi, and loads of other variants too. If you want a really strong opponent, you can download the WinBoard Shogi Variants Package, which includes HaChu, a computer engine designed specifically to play Chu Shogi (it also plays a mean game of Sho Shogi and Dai Shogi). Apparently HaChu can play a pretty great game of Tenjiku Shogi nowadays too, although this version is not yet released — when it is, you’ll want to download WinBoard Alien Edition to play the larger Shogi variants.

Anyway, please pick one of those options and give Chu Shogi a go — it may take a game or two to sink in, but if nothing else I’m sure you’ll understand how this game managed to survive for 600 years, even in the face of the massive popularity of modern Shogi. You may even find it becomes an all-time favourite, as it has for me.

Even better, once you learn Chu Shogi you can easily pick up the larger Shogi variants — you could learn Dai Shogi in a few minutes, and Tenjiku Shogi in an afternoon. I’ll be covering both these games in later posts, too, including a little piece on why Dai Shogi is more than just Chu Shogi’s older, slower big brother. Tenjiku will speak for itself — that game is like nothing else out there and has a deservedly strong reputation.

In future instalments of this Chu Shogi series I’ll cover more detailed tips for Chu Shogi, including building castles for defense and developing checkmating attacks. I’ll also fully annotate a game of Chu Shogi, talking through the moves and hopefully giving you more insight into the strategic depths this game has to offer.

Tagged Chu Shogi, Dai Shogi, Games, Sho Shogi, Shogi, Shogi Variants

Science, Philosophy and Miscellaneous Musings

Tag Archives: Shogi Variants

The Birth of Shinjuu Shogi

Design Goals

Meet Shinjuu Shogi

Gameplay

The Pieces of Shinjuu Shogi

A Closer Look

Lessons Learned

Next Moves

Tenjiku Shogi (16×16)

Rulesets and Options

Promotion Rules and 50 Move Rule

Tenjiku Sub-Variants

Nutty Shogi (13×13)

Makyou Shogi (12×12)

Dai Dai Shogi (17×17)

Rulesets and Options

Sub-Variant: Cashew Shogi

Maka Dai Dai Shogi (19×19)

Rulesets and Options

Sub-Variant: Macadamia Shogi (13×13)

Sub-Variant: Hishigata Shogi (19×19)

Tai Shogi (25×25)

Rulesets and Options

Sub-Variant: Mini Tai Shogi (15×15)

Emperor Endgame Trainer

Rulesets and Options

Shogi-Inspired Chess Variants

Rider Romp (10×10)

Neutronium Chess (12×12)

Dai Chess (15×15)

Expanded Chess/Get Bent/Symmetric Sissa

Next Moves

Frequently Asked Questions

“How can I choose a Shogi variant to play?”

“How can I play online?”

“I’m playing Tenjiku Shogi, how do I use igui capture with my Heavenly Tetrarchs?”

“I can’t visualise these crazy moves! Can Ai Ai show me where my pieces can go?”

“How can I change the AI settings?”

“How can I see all the piece types present in each game?”

“Why are the piece abbreviations in the move notation different from the previous convention?”

“How do I make those cool animated GIFs of my games?”

“How can I tinker with the AI and try to improve it?”

“I have a great idea for a modern variant of these games! Can you make it for me?”

“I don’t like the default options you chose for some of these games, and I’m tired of changing them every time. Can I change them permanently?”

“Why does the AI struggle with these large Shogi games?”

“Hey Eric, why didn’t you include [my preferred rule]? It’s clearly superior because….”

“Hey Eric, why did you include stuff nobody plays anymore, like Hodges’ moves for the Lion Hawk and Free Eagle?”

“Hey Eric, why didn’t you include my Shogi variant?”

Furious Fiend (promoted Lion)

Great Elephant

Conclusions

Next Moves

The Origins of Dai Shogi

The Rules

The Basics

The New Pieces

Why play Dai Shogi?

Basic tips for beginners

The Opening

The Middlegame

The Endgame

Final thoughts

Tsumeshogi Solutions

Building Castles in Chu Shogi

Attacking Principles in the Middlegame

Tips for Specific Pieces

The Endgame

Tsumeshogi

An interesting quirk in the Lion-trading rules

Tsumeshogi Solutions

The final installment

What is Chu Shogi?

The Origin of Chu Shogi

The Rules

Winning the game

The Bare King Rule

Taking a turn

Repeating positions