Dr Eric Silverman

UPDATE 6 Nov 2021 — Added info and screenshots on playing Courier Chess and Courier-Spiel in Ai Ai.

As some of you may know, I’m a big fan of the large-board variants of Shogi, Japanese Chess.  These enormous games extend Shogi out from its normal 9×9 board with 20 pieces per player, up to Chu Shogi (12×12 with 46 pieces per player) and Dai Shogi (15×15 and 65 pieces per player), then through progressively more enormous boards and armies, all the way out to the ludicrous Taikyoku Shogi (36×36 with 402 pieces per player).  Not all of these games are particularly practical to play, at least not regularly, but the best among them use these large playing surfaces and diverse armies to create gargantuan strategic battles stay thrilling even over the course of hundreds of moves.

Large-Board Chess in History

Of course, Western Chess has a long history of variants.  A number of larger Chess games have been developed over the centuries as well, right from the earliest days of the game.  Shatranj, the ancient Arabic ancestor to Chess, was extended to the 10×10 board back in the 9th century to create Shatranj al-Tamma, or Complete Chess.  Inspired by Shatranj al-Tamma, Turkish Chess fanatics developed a family of enlarged ‘Turkish Great Chess‘ variants, ranging in size from 10×10 boards to 14×14.  Some other variants of Shatranj went off in some remarkably creative directions, such as Tamerlane Chess, where additional citadel squares hang off the 10×11 board and numerous new piece types appear.

At the time these games were invented, the pieces used in Chess were slower than today, with only the Rooks able to move unlimited distances.  That meant that on these larger boards the play tended to be rather slow, and while some may have appreciated the deliberate, strategic flavour this provides, some of these large-board games felt fairly ponderous.  Tamerlane was an exception, however; the piece density on the board was high and the board was shorter vertically as well, meaning that the opposing armies took less time to get into conflict.  The wide variety of pieces in Tamerlane also diversified play and provided some new tactical wrinkles compared to the smaller game.  Atranj and Indian Great Chess are also quite playable, largely because they include some powerful compound pieces (Bishop + Knight, Rook + Knight, Knight + Queen) that can range across the board very quickly and considerably speed up play.

Unfortunately, these more successful large variants still never quite established a significant foothold in the Chess-playing world, and most of these games have since disappeared and are now merely historical curiosities.  Tamerlane is still known to a degree, due to its unique character, but the others are long gone.  Generally speaking, historical large Chess variants came and went fairly quickly; clearly many players desired a larger game given the sheer number of attempts, but few games managed to maintain a following for very long.  Given that even the 10×10 variants had trouble finding players, none of the historical large Chess games were nearly as adventurous as the large Shogis, in terms of size, piece count or rules variation.  I suspect if these enlarged games had taken hold, we may well have seen Chess-based equivalents of the gargantuan Shogis.

Courier Chess

However, there is one large-board Chess variant that did have longevity — Courier Chess.   Courier Chess is believed to have originated around the 12th century, with its first known appearance being a tale written by Wirnt von Gravenburg in 1204 called the Wigalois.  Courier Chess is mentioned regularly in subsequent centuries, mostly in medieval German poetry, but its most famous appearance is in the painting The Chess Players by the Dutch master Lucas van Leyden in 1510:

The gentleman on the left looks a bit chagrined, and he has every right to be — analysing the board position shows that the woman on the right will achieve checkmate in three moves!

As we can see in the painting, Courier Chess is immediately remarkable for its elongated board; the playing area is 12×8 (96 squares).  In order to fill in the 12 ranks in each player’s camp, some additional pieces are added to the lineup as well.  The Courier starting position looks like this:

The starting array for medieval Courier Chess.

Moving along the first rank from left to right, this is the piece lineup: Rook; Knight; Elephant; Courier (Bishop); Sage; King; Queen (Ferz); Fool; then we have the Courier, Elephant, Knight and Rook again.  In keeping with Chess convention, the second rank is filled with Pawns to protect our valuable pieces.

While there are clearly some pieces here that aren’t in the standard medieval Chess lineup, what is most remarkable about the Courier Chess piece assortment is that this game marks the first recorded appearance of the modern Bishop.  This piece actually gives the game its name — what we would call the Bishop is called the Courier here.  At the time, most Chess players would have been playing some medieval variant of Shatranj where Rooks were the only long-range pieces, so having these Couriers slicing diagonally all over this extended board must have been a thrilling change from the standard game.  Confusingly, what I have portrayed here as Elephants were actually called Bishops in the original Courier Chess, but given their moves match the Elephant of Shatranj, I am using that piece instead to prevent any mix-ups with the Courier.

In Courier Chess the most powerful pieces on the board are the long-range Rooks and Bishops, followed by the always-tricky Knight.  From there we have an array of short-range pieces of varying abilities.  This diagram shows the moves of every available piece type — yellow circles indicate a stepping move; red circles indicate spaces where a piece can only capture; solid arrows indicate a sliding move over any number of squares in that direction; and dashed arrows represent leaps directly to the square indicated:

The pieces in Courier Chess generally follow the conventions of medieval Chess in place at the time:

• The Pawn moves one square forward only, or may capture an enemy piece diagonally forward to the left or right.  Unlike modern Chess, Pawns only ever move one square — there is no initial double-move available, and therefore there is also no en passant capture rule.  When Pawns reach the opponent’s back rank, they promote to Queen (Ferz).
• The Sage moves one step to any adjacent square, just like the King, but it’s just a normal piece — no worries about check or checkmate.
• The Fool moves one step horizontally or vertically only; this move derives from the Shatranj piece called a wazir.
• The Queen is far, far weaker than the ‘Mad Queen’ we are accustomed to in modern Chess — it moves only one square diagonally.  This move derives from a Shatranj piece called the ferz.
• The Elephant (which again would have been called the Bishop in the original game) moves as an alfil in Shatranj, a diagonal leap of two squares, jumping over any pieces on the square in between.  The Elephant is thus colourbound — it will only ever be able to visit squares of the same colour it starts on.  In fact, the Elephants may only visit a quarter of the squares on the board!
• The Knight moves just like in modern Chess — a leap of one square horizontally or vertically, followed by one square diagonally, jumping over any intervening pieces.
• The Rook moves as in modern Chess as well, sliding any number of squares vertically or horizontally.  Note that there is no castling in Courier Chess.
• The Courier moves as the modern Bishop, sliding any number of squares diagonally.  Like the Elephant, it is also colourbound, forever stuck on either the light squares or dark squares.

As in modern Chess, the goal is to checkmate the opposing King.  However, we do not know the precise rule for stalemate, where the King is not in check but has no legal moves; given the conventions of Shatranj and medieval Chess we might expect that stalemate in Courier is a loss for the opposing player, rather than a draw as in modern Chess.

Intriguingly, before starting the game both players would traditionally mvoe the A, G and L Pawns forward two squares, then move the Queen up just behind her Pawn.  These special Pawn moves were called ‘joy leaps’ and were not available during the rest of the game; these may well be the first known examples of a double Pawn move in Chess.  Presumably these initial moves were done so as to open up the position from the start and encourage the players to develop their slower-moving pieces.  So, before starting the game proper, the Courier board would look like this:

Remarkably for a medieval Chess variant on a large board with many slower pieces, in actual play Courier is quite a lively game.  The pre-advanced Pawns mean the Rooks can be developed quickly, despite the lack of castling, and the forward Queen allows some cover for further Pawn advances to attack the centre.  The Knights and Elephants can leap into the action right away, while the Sage and Fool mostly hang back to protect the King from all these spiky Couriers swirling around the board.  A typical game of Courier will generally take longer than a game of Chess, but not as long as you might think; most of my games against the computer last about 60-70 moves per player, as opposed to around 40 for modern Chess.  However, two strong players of near-equal ability could easily end up locking horns for far longer.

Thanks to Courier’s interesting board shape, varied yet easy-to-remember set of pieces, and enjoyable play, the game was able to last for about 600 years in the parts of Germany where it was most popular.  The game did start to die off in the 19th century, however.  At that time, standard Chess had matured essentially into the form we know today, and the fast-paced action and compact game length of the 8×8 Royal Game certainly worked to its advantage.

Courier-Spiel

Despite the increasing dominance of standard Chess, some dedicated fans did want Courier to make a comeback.  In 1821, H.G. Albers of Lüneburg proposed an updated version of Courier Chess, which he dubbed Courier-Spiel (The Courier Game).  Albers cleverly updated the pieces and rules of the game to increase the pace and tactical richness, making it more competitive with standard Chess.

Courier-Spiel updates the classic Courier experience with some more modern rules and more powerful pieces:

Starting again from the bottom-left corner and moving to the right, this is our new starting lineup: Rook; Knight; Elephant; Bishop; Councillor; King; Queen; Sage; then completing the set with Bishop, Elephant, Knight and Rook once again.  Courier-Spiel thus has some new pieces and some changes to the old ones:

The moves of the pieces in Courier-Spiel.

• Pawns move as in modern Chess — one square forward and capturing on the forward diagonal squares, but they may also take an initial two-step move from their starting square only.  En passant capture is now possible.  Pawns that reach the opponent’s back rank promote in an unusual way — they must sit on the back rank for another two moves, and then finally promote on the third move to any piece from the Pawn’s army that has been previously captured.  If no pieces have been captured from their army yet, then promotion is impossible, and the Pawn must sit on the back rank until a captured piece is available.  We are not entirely sure whether these Pawns are vulnerable while waiting for promotion, but modern players seem to have settled on making them immune to capture until promotion occurs.
• The Sage moves the same as in Courier Chess — one step to any adjacent square.  The Sage is now next to the Queen rather than the King.
• The Fool has had a significant upgrade, and now moves like a combination of the King and Knight.  This powerful new piece sits next to the King where the Sage used to be.
• The Queen is no longer a ferz, but instead functions exactly like a modern powerhouse Chess Queen — moving any number of squares vertically, horizontally or diagonally.
• The Elephant is stronger too, and now moves as a combination of alfil and ferz — it may move one step diagonally, or leap two squares diagonally.  They are still colourbound like the Elephants in Courier.
• The King, Knights and Rooks move the same as in Courier Chess.
• Rules-wise, of course the goal of the game as usual is to checkmate the enemy King.  I have not seen a definitive statement of the stalemate rule, but as far as I am aware modern players have stalemate as a draw in this game.  Courier-Spiel does not use the initial ‘joy leaps’ of the Pawns and Queen that were customary in Courier Chess.

Along with the modernised Pawns, players may now castle in Courier-Spiel.  As in modern Chess, in order to castle the path between the King and the Rook must be clear of any other pieces, and neither piece must have already moved.   Castling may not be done if either the King or the Rook is under attack by an opposing piece, or if any of the intervening squares are under attack.  To castle, the King will move to the C file (if castling with the A-file Rook) or the J file (if castling with the L-file Rook), then the Rook leaps over to the space adjacent to the King on the opposite side:

Castling example.

Taking all these adjustments together, Albers did a good job updating Courier for a more modern era.  The increased power of the Elephants, Sage, Fool and particularly the Queen significantly increase the pace of the game.  Tactical exchanges are more frequent than in the original as well.  The addition of castling prevents too many early wins by allowing the King a quick path to safety.  The removal of the initial ‘joy leaps’ of the A, G and L Pawns also allows the King further protection, and avoids a prematurely-developed Queen.  Cleverly, the newfound single-square diagonal move of the Elephant also serves to protect the B and K Pawns, which previously were unprotected and thus vulnerable to early attack in Courier.  Finally, the increased powers of the Sage and Fool provide some strong checkmating powers in the late game, and are also strong defensively, preventing the deadly Queen from completely dominating play.

The glaring flaw in Courier-Spiel is of course the promotion rule, which adds some serious rules complications while also significantly slowing down the process of Pawn promotion.  This leads to some weird pacing in the endgame, where the typical race to promote Pawns becomes a strange, cagey stand-off instead.

However, there is historical precedent here that likely encouraged Albers to adopt this strange promotion method.  In the version of Courier played in Ströbeck, Germany’s famous ‘Chess Village’, the Pawns must go through an odd ritual in order to promote.  Upon reaching the opponent’s back rank, the Pawn would have to make a series of three double-step jumps backward, each one taken on a separate turn (the Pawn’s controlling player did not have to do these jumps immediately or consecutively, but could do them whenever the board situation was convenient).  Pawns making these leaps cannot capture this way, but they can be captured.  After the third backward leap, the Pawn would have returned to its starting square and could then promote immediately into another piece (any piece, not just the Queen).

Given this odd promotion rule was in use in the past, perhaps Albers adopted a version of it to avoid altering the feel of the Courier Chess endgame beyond what Courier fans may have been willing to tolerate?  In any case, I suspect most modern players would prefer to replace these three-turn promotion rules with the simpler method of the original Courier Chess, and just allow Pawns to promote immediately upon reaching the enemy’s back rank.

Playing Courier Chess and Courier-Spiel

While neither of these variants are played widely today, thanks to the internet and powerful Chess-playing engines we need not be short of opponents.  Perhaps the most promising way to find human opponents would be to sign up for an account at the Chess Variant Pages, and then use their Game Courier (how appropriate) Play-By-Email system to invite someone to a game.  Courier Chess has a setup available on Game Courier, and a fair few games have been played, so probably someone will take you up on the offer.  Courier-Spiel has some fans as well.

Since I wrote the first version of this article, I began working with Stephen Tavener on his wonderful Ai Ai general game-playing software.  I work primarily on the Chess/Shogi side of things, and have added many dozens of variants in recent months.  We of course added implementations of Courier Chess and Courier-Spiel, so you may play both these games against AI or human opposition:

As you can see, the piece graphics are slightly different — the Queen and Fool have been replaced with the generic Ferz and Wazir, respectively, but the piece images are schematic and easy to remember.  Subsequently I have added a number of Courier-inspired modern variants to Ai Ai; more on these in a future article!

Alternatively, if you want to play against a tougher AI, you can download WinBoard and play Courier Chess against the FairyMax computer engine.  This is quite an enjoyable way to get to know the game, and FairyMax is a decent opponent.  WinBoard does not appear to have a Courier-Spiel setup available by default, but it is possible to define your own variants.  Winboard supports variants all the way up to Tai Shogi and its 25×25 boards, so feel free to experiment with your own wild expansions of Courier Chess.

If you are looking for a real challenge, download the Fairy-Stockfish engine, which also supports Courier (and you can define Courier-Spiel very easily, check the file ‘variants.ini’ under the ‘src’ folder in the GitHub repository at the link).  Fairy-Stockfish is based on Stockfish, one of the strongest Chess engines on the planet, so it is an absolutely brutal opponent!  Conveniently, Fairy-Stockfish also supports a tonne of other good Chess variants, although due to engine limitations it cannot play any game with a board larger than 12×10 (although this may change further down the line).

For playing Courier Chess on the go, you can grab the Chess Remix app for your Android phone or tablet.  This great little app contains over 100 Chess variants, including many of the major regional and historical ones.  Alongside Courier, Tamerlane Chess, Chu Shog and Dai Shogi are in there, too.  The piece graphics are little pixel-art representations of the moves of each piece, which is probably helpful for some but I personally am not a huge fan of that approach.  As a Shogi purist who loves Japanese calligraphy, playing the Shogi family without the kanji characters feels particularly wrong and gross, but I do enjoy having the ability to play all of these games on the go.  Chess Remix, true to its name, also lets you create your own variants or modify the included ones in all sorts of different ways, so it is a must-have if you enjoy mucking around with Chess.

Playing Courier Chess against the AI in Chess Remix.

Over-the-board Courier play is a bit more challenging to arrange due to the lack of any 12×8 boards on the market, although some chessboard specialists may be able to make one to order.   There are some occasional reproductions available based on the Courier Chess set depicted in van Leyden’s painting, but these are handmade and the pieces are brass, so they are quite expensive!  A better option may be to buy a couple of inexpensive vinyl or neoprene chess boards, slice one in half and attach it to the other.  For pieces, a couple of regular Chess sets plus some variant pieces would be sufficient.

However, if you are willing to be a bit patient, the Chess Club of Ströbeck is planning to produce a run of Courier Chess boards and pieces sometime in 2021.  The boards will be handmade, and without a doubt these sets will be a fine collector’s item as well as being great for play.

Next moves

The second part of this series will examine some modern extensions of the Courier Chess concept, all of which are available to play in Ai Ai.  I had previously planned to present some analysed games of Courier and Courier-Spiel, but due to a backup mishap I lost the substantial work I’d already done on these.  At some point I’ll do that work again, but for my own sanity I need some time before I dive back into that analysis a second time!

In the meantime, please give Courier Chess and Courier-Spiel a try — in my opinion they are easily among the most interesting historical Chess variants, offering a unique feel and entertaining strategic dilemmas.  Courier’s distinct medieval feel and pacing is surprisingly absorbing, and while the modernised takes on it are probably more polished games, I still find myself returning more often to the 800-year-old original.  Certainly Courier will not appeal to everyone, but I feel every Chess fanatic owes it to themselves to experience this unique offshoot of the medieval game.