is the largest known variant of shogi (Japanese chess). The game was created around the mid-16th or 17th centuries (presumably by priests) and is based on earlier large board shogi games. Before the rediscovery of taikyoku shogi in 1997, tai shogi was believed to be the largest physically playable chess variant ever. It has not been shown that taikyoku shogi was ever widely played. There are only two sets of restored taikyoku shogi pieces, one of which is held at Osaka University of Commerce. The only played game in recent history was played in 2004 for the Japanese television show The Fountain of Trivia (Fuji Television), which took 32 hours and 41 minutes, spanning over three days, and a total of 3,805 moves.
Because the game was found only recently after centuries of obscurity, it is difficult to say exactly what all the rules were. Several documents describing the game have been found; however, there are differences between them. It is not clear how accurate the rules given by modern sources for the game are, because many of the pieces appear in other shogi variants with a consistent move there, but are given different moves in taikyoku shogi. The board, and likewise the pieces, were made much smaller than usual for the other variants, making archaeological finds difficult to decipher. Research into this game continues.
Taikyoku shogi is very different from other large-board shogi variants: tenjiku shogi, dai dai shogi, maka dai dai shogi, and tai shogi. The most notable differences lie with the piece movements and their promotions.
Objective
The objective of the game is to capture the opponent's king(s) and crown prince(s). When the last of these is captured, the game ends. There are no rules for check or checkmate; however, in practice a player resigns when checkmated. Unlike standard shogi, pieces may not be dropped back into play after being captured.
Game equipment
Two players, Black and White (or 先手 sente and 後手 gote), play on a board ruled into a grid of 36 ranks (rows) by 36 files (columns) with a total of 1,296 squares. Each "square" is a 17mm by 15mm rectangle, making the playing size tantamount to 65 cm by 55 cm. The squares are differentiated by marking or color.
Each player has a set of 402 wedge-shaped pieces of 207 types. The players must remember 253 sets of moves. The pieces are of slightly different sizes with the larger pieces near the king and becoming progressively smaller for pieces further from the king, regardless of power. In general, the stronger pieces are nearer to the king.
Each piece has its name in the form of two or three kanji written on its face. On the reverse side of some pieces are two or three other characters, often in a different color (commonly red instead of black); this reverse side is used to indicate that the piece has been promoted during play. The pieces of the two sides do not differ in color, but instead each piece is shaped like a wedge, and faces forward, toward the opposing side. This shows who controls the piece during play.
Listed below are the pieces of the game and, if they promote, which pieces they promote to. Promotions prefaced with a star are not also represented as their own pieces, existing only as promotions.