Chu shogi

How Chu shogi is played

Chu shogi, “middle shogi”, is the large shogi of medieval Japan: 46 pieces a side on a board of twelve squares by twelve, without drops. The goal is to take the opponent’s king, and its prince if it has one; a mate ends the game too.

The board and the start

Sente, at the bottom, moves first. Each side has twelve pawns on its fourth rank and two go-betweens in front of them. The promotion zone is the last four ranks, from the opponent’s pawns on.

The pieces

Most pieces step one square in some directions or slide as far as they like in others: the queen (free king) slides every way, the dragon king like a rook plus one step diagonally, the dragon horse like a bishop plus one step straight; the side and vertical movers slide along one line and step along the other. The kirin steps diagonally or jumps two squares straight, the phoenix steps straight or jumps two squares diagonally. Lifting a piece shows where it can go.

The lion

The lion moves as a king twice in one turn, in any directions: it may take a piece with the first step and go on, taking a second piece with the second, or come back to its square (igui: it takes a neighbour without moving). It may also jump to any square two away, over anything. Stepping out and back through an empty square passes the turn (jitto).

The horned falcon and the soaring eagle

The horned falcon (a promoted dragon horse) slides every way but forward; forward it has the lion’s moves, one or two squares. The soaring eagle (a promoted dragon king) slides straight and diagonally back; along both forward diagonals it has the lion’s moves.

Trading lions

A lion may always take a lion next to it. A lion two squares away may not be taken by a lion if it is protected, unless the capturing lion first takes another piece on the way, not a pawn or a go-between. After a lion is taken by any other piece, the other side may not take a lion with another piece on its next move, except on that same square.

Promotion

A piece may promote when it enters the zone, or when it captures on a move that starts or ends in it; a quiet move inside the zone does not promote. Promotion is never forced. A pawn may also promote on reaching the last rank, and a pawn or lance may stay there unpromoted. A promoted piece never promotes again, even when it moves like a starting piece.

The king and the prince

The drunk elephant promotes to the prince, which moves as the king and is royal too: a player loses only when both are taken. Moving into check is allowed; a king left attacked can be taken. Check counts only against a player’s last royal.

Winning

Taking the opponent’s last royal wins, and so does a mate. A player who cannot move loses. A player left with the king alone loses against a king and another piece that is not a pawn or a go-between.

Draws

Kings alone draw. When a position comes for the fourth time, a player who checked or attacked with every move since it first came loses; otherwise it is a draw. Two hundred moves without a capture or promotion draw too.

Other readings

The rules are lishogi’s, which most sources give. The Japan Chu Shogi Association lets a non-lion retake a lion at once if the capturer’s own lion is protected (Okazaki’s rule), and gives the side that repeats the position the duty to change.

The story

Japan · first named about 1350

When and where

Chu shogi, “middle shogi”, came from the great dai shogi of 15 × 15 squares in the early 14th century, when the Japanese played shogi in three sizes, and is first named about 1350. It is not the parent of today’s shogi but its cousin: both come from the shogi of the Heian period.

How it changed

It left out dai shogi’s eight weakest kinds of piece and kept 46 pieces a side of 21 kinds on 12 × 12 squares, without drops. Its star is the lion, which moves twice in one turn. In the 15th and 16th centuries it was the game of the court; when drops came to small shogi, small shogi won the players.

Today

Books of the Edo period wrote it down, among them a rule book of 1703 and four collections with 224 mating problems. It lived on in the Kansai, where the great professional Ōyama Yasuharu learned it as a boy in 1937. By 1975 only about ten people in Japan were said to play it; the Japan Chu Shogi Association (2000), the town of Shimamoto near Osaka and lishogi (since 2022) have revived it.

Did you know?

Ōyama wrote that chu shogi shaped his cautious, tenacious style, and called the lion a monster that devours whatever comes near, yet goes hungry in the endgame. The rules against trading lions exist, the association says, because the game turns dull without them.

Original piece names

gyokushō (king) · suizō (drunk elephant, it becomes the prince) · kirin · hōō (phoenix) · shishi (lion) · honnō (free king, the queen) · ryūō, ryūma (dragon king, dragon horse) · hisha, kakugyō (rook, bishop) · mōko (blind tiger) · mōhyō (ferocious leopard) · kinshō, ginshō, dōshō (gold, silver, copper general) · shugyō, ōgyō (vertical and side mover) · hensha (reverse chariot) · kyōsha (lance) · chūnin (go-between) · fuhyō (pawn)

Sources: Wikipedia · Japan Chu Shogi Association · lishogi

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Chess and variants

• Chess · Classic chess, or Chess960 with a shuffled back rank.
• Chess960 · Fischer random chess: the back rank starts in one of 960 setups.
• Antichess · Losing chess: give away all your pieces, captures are compulsory.
• Atomic chess · Every capture is an explosion that clears the pieces around it.
• Crazyhouse · Captured pieces change sides and can be dropped back onto the board.
• Hostage chess · Captured men become hostages and come back by exchange or from the airfield.
• Three-check · Chess where the third check wins, so every check counts.
• King of the Hill · Chess where a king that reaches the centre wins at once.
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• Racing Kings · No pawns, no checks: the first king on the far rank wins.
• Horde · 36 white pawns storm a full black army.
• Dunsany’s chess · Lord Dunsany’s game of 1942: 32 pawns against a full army.
• Los Alamos chess · Chess on 6 × 6 without bishops, the first game a computer played (1956).
• Duck chess · After every move you move the duck, which blocks everyone. No check.
• Marseillais chess · Two moves a turn, with one piece or two; White starts with one.
• Progressive chess · One move, then two, then three: each turn is one move longer.
• Fog of War · You only see where your pieces can move. Capture the king to win.
• Kriegspiel · Only your own pieces in sight; an umpire judges every move.
• Alice chess · Two boards: every piece that moves passes through to the other one.
• Raumschach 3D · Chess in a 5 × 5 × 5 cube: five boards stacked, and the unicorn.
• Old Raumschach · Maack’s cube as played before 1919: five pawns above the pieces.
• Friendly Chess · Nothing is captured: pieces unite and set off chain reactions.
• Ultima · Every piece captures its own way, and the immobilizer freezes.
• Gliński’s hexagonal chess · Chess on 91 hexagons: three bishops, rooks in six directions.
• McCooey’s hexagonal chess · Hexagonal chess closer to chess: seven pawns that take diagonally.
• Shafran’s hexagonal chess · Hexagonal chess on 70 cells, with castling and pawns that step three.
• Spartan chess · Persians against Spartans: chess’ army against two kings and new pieces.
• Legan chess · The armies in opposite corners; pawns step diagonally towards the far one.

Big chess

• Complete chess · The Arabic chess of the 9th century on 10 × 10, with two dabbābas a side.
• Courier chess · Medieval Germany’s chess on a 12 × 8 board, with the courier, the man and the schleich.
• Grande Acedrex · Alfonso X’s great chess on a 12 × 12 board, with lions, giraffes and a roc.
• Tamerlane chess · Timur’s great chess on an 11 × 10 board, with giraffes, camels and citadels.
• Carrera’s chess · The first chess on ten files, from a Sicilian priest’s book of 1617.
• Duke of Rutland’s chess · Fourteen files, with the concubine and two crowned rooks a side.
• Bird’s chess · Henry Bird’s ten-file chess of 1874, with the guard and the equerry.
• Capablanca chess · Ten files and two new pieces: the archbishop and the chancellor.
• Gothic chess · Ed Trice’s setup of 2000, today called Trice’s Chess.
• Capablanca Random · Capablanca chess from one of 12,118 shuffled starts.
• Embassy chess · Grand chess’ row of pieces on a 10 × 8 board.
• Janus chess · Two januses a side, each moving as a bishop or a knight.
• Grand chess · Christian Freeling’s 10 × 10 game: pawns promote only to lost pieces.
• S-chess · Chess with a hawk and an elephant in hand, placed as the back rank leaves.

The chess family

• Chaturanga · India’s ancient chess, the root of the family: take the king to win.
• Shatranj · The medieval ancestor of chess, with a weak ferz and a jumping alfil.
• Byzantine chess · Shatranj on a round board: the rook circles, pawns never promote.
• Medieval chess · Europe’s chess before 1475: the ferz and the king may leap on their first move.
• Senterej · Ethiopian chess: no turns until the first capture, then Shatranj.
• Shatar · Mongolian chess: the bers, the camel, and a mate that needs a shak.
• Makruk · Thai chess: a slow, strategic game with a counting rule.
• Ouk Chatrang · Cambodian chess: Makruk with a leap for the king and the met.
• Sittuyin · Burmese chess: set up your pieces, then promote on the diagonals.
• Kar Ouk · Ouk Chatrang where the first check wins: guard your king.
• Malay chess · Chess of the Malay world: the king leaps, a crowned pawn walks back.
• Xiangqi · Chinese chess: a river, palaces and a cannon that jumps to capture.
• Minixiangqi · Xiangqi on 7 × 7 points: no river, no advisors, no elephants.
• Manchu chess · Red’s lone chariot moves as horse and cannon too, against a full army.
• Jieqi · Xiangqi with the pieces face down: each is revealed by its first move.
• Banqi · Xiangqi’s pieces face down on half a board: turn them up, take by rank.
• Janggi · Korean chess: no river, palace diagonals and a cannon that always jumps.
• Shogi · Japanese chess: captured pieces return to the board on your side.
• Minishogi · Shogi on a 5 × 5 board: six pieces a side, short and sharp games.
• Tori shogi · Bird shogi on 7 × 7: a phoenix, quails and swallows, with drops.

More players

• Chaturaji · India’s four-handed chess: kings can be captured, captures score.
• Four Seasons Chess · Alfonso X’s chess for four from 1283: four seasons, the last king wins.
• Three-player chess · Three armies on a hexagonal board: you against two bots.
• Four-player chess · Four armies on a cross-shaped board: in teams or all against all.
• Bughouse · Two boards, two teams: what you capture goes to your partner's hand.
• Eight-player chess · Eight armies on a board of 516 squares: all against all, in pairs or four against four.
• Verney’s four-handed chess · Verney’s game of 1881: two against two, mate both enemy kings.
• Verney’s eight-handed chess · Verney’s game for eight of 1884: four against four on 448 squares.