Ko shogi
The game dates back to the turn of the 18th century and is based on xiangqi and go as well as shogi.
Credit for its invention has been given to Confucian scholar Ogyū Sorai (1666–1728), who had also described the rules of the game in his book, Kōshōgifu (廣象棋譜).
[1][2] Unlike standard shogi, pieces may not be dropped back into play after being captured.
The objective is to capture the opponent's commanding pieces: The general, plus, if present, the governor; otherwise, the banner or middle army.
Two players, Black and White, play on a go board ruled into a grid of 19 ranks (rows) by 19 files (columns) with a total of 361 intersections.
At the beginning of the game the cavalryman and cavalry are exceptions in that they do not move in a prime direction.
(The banner and drums, dragon ascending, war hawk, winged horse, and several other pieces are similar, but they only appear with promotion.)
The step movers at the beginning of the game are the general, aide de camp, aide, staff, chief of staff, engineer, middle troop, drum, banner, sentry, Frankish cannon, long bow, crossbow, shield, and pawn.
The jumping pieces at the beginning of the game are the clerk, staff officer, Taoist priest, spiritual monk, cavalryman, and cavalry.
Many pieces can move any number of free intersections along a straight line, limited by the edge of the board.
If an opponent's piece intervenes, it may be captured by moving to that intersection, and removing it from the board.
The sumo wrestler and cavalry have double-move with double-capture abilities, similar to the 'lion move' in chu shogi.
Among the promoted pieces, the master at arms, banner and drums, five-li fog, thunderclap, flag waver, dragon ascending, tiger wing, war hawk, and winged horse have multiple-capture abilities.
By default continuation legs can go into all directions, but can be restricted to a single line by a modifier 'v' ("vertical", interpreted relative to the piece's current position on its path).
Similarly, the modifier 'f' ("forward") would restrict it to a single line, and force it to always move away from its initial position.
The default modality of all legs is the ability to move and capture: other possibilities are specified explicitly.
The dragon arising adds the moves of the sumo wrestler 力士 to those of the millenary.
A player is not allowed to give perpetual check to the sole objective piece.
A player who captures the opponent's general 将 and either the middle troop 中軍 or the banner 旗 wins the game.
That is, a player can continue the game with either the general, or the governor, or with both the middle troop and the banner together.
In practice the final capture rarely happens, as a player will resign when checkmated, as otherwise when loss is inevitable.
The method used in English-language texts to express shogi moves was established by George Hodges in 1976.
If a piece captures by 'igui' (possibilities are the sumo wrestler, dragon ascending, tiger wing, cavalry, winged horse, five-li fog, immaculate light, banner and drums, or master at arms), the intersection of the piece being captured is used instead of the destination intersection, and it is preceded by the symbol '!'.
