Кóсёги: Большая разновидность японских шахмат

Large board variant of shogi, or Japanese chess

Kō shōgi (広将棋 or 廣象棋 'broad chess') is a large board variant of shogi, or Japanese chess. 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).

Unlike standard shogi, pieces may not be dropped back into play after being captured. Promotion rules are complex, and the fates of several pieces are interdependent.

The objective is to capture the opponent's commanding pieces: The general, plus, if present, the governor; otherwise, the banner or middle army.

The players alternate making a move, with Black moving first. A move consists of moving a piece on the board and potentially capturing a piece or pieces and promoting a piece or pieces. Each of these options is detailed below.

An opposing piece is generally captured by displacement: That is, if a piece moves to an intersection occupied by an opposing piece, the opposing piece is displaced and removed from the board. A piece cannot move to an intersection occupied by a friendly piece (that is, a piece controlled by the same player). Each piece in the game moves in a unique manner. Most pieces move in one of eight prime directions, either orthogonally (that is, forward, backward, or to the side, in the direction of one of the arms of a plus sign, +), or diagonally (in the direction of one of the arms of a multiplication sign, ×). 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.) Many pieces are capable of several kinds of movement, with the type of movement usually depending on the direction in which they move. The most common kinds of moves are step, range, shoot, and jump.

Some pieces can move only one intersection at a time. (If a friendly piece, and sometimes an enemy piece, occupies an adjacent intersection, the moving piece may not move in that direction. Unlike in Go, 'adjacent' means any of eight intersections.) 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.

Some pieces can move along a limited number of free intersections along a straight line. Other than the limited distance, they move like range pieces (see below). The limited range pieces at the beginning of the game are the chariot and the vanguard.

Several pieces can jump, that is, they can pass over an intervening piece, whether friend or foe. 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. A range piece must stop where it captures, and cannot bypass a piece in its way. If a friendly piece intervenes, the moving piece is limited to a distance that stops short of the intervening piece; if the friendly piece is adjacent, it cannot move in that direction at all. The ranging pieces at the beginning of the game are the advance guard, millenary, quartermaster, centuria, rear guard, elephant, patrol unit, shield unit, and chariot unit.

Some pieces can shoot, that is, they can remove a piece from the board a limited distance from their location. Except for the cannon, they cannot shoot an enemy piece if another piece stands between the shooter and its target. The cannon, however, can shoot over such intervening pieces. It is not clear if a piece must move in order to shoot. The rule that a piece must move to shoot comes from Kōshōgifugukai. The original source (Kōshōgifu) doesn't have such a rule, while it also doesn't make it clear under what circumstance a piece can shoot. The shooting pieces at the beginning of the game are the Taoist priest, spiritual monk, Frankish cannon, long bow, crossbow, and cannon.

Wherever a burning piece arrives at an intersection, all adjacent enemy and allied pieces are removed from the board, as described below. The only burning piece is the poison flame, which only appears with promotion.

The skyward net and earthward net have the ability to immobilize enemy pieces in their ranging directions.

The sumo wrestler and cavalry have double move with double capture abilities, similar to the 'lion move' in chu shogi. Unlike the lion, they are merely double move pieces and do not have the ability to bypass a friendly piece occupying the first landing point. Unless stated otherwise below, the multiple moves do not need to be in the same direction and need not all be taken. A second or later move may return a piece to its starting location. 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. The Frankish cannon has a double kill ability when it shoots.

In the diagrams below, the different types of moves are coded by symbol and by color: Blue for step moves, green for multiple capture, red for range moves, and yellow for jumps. Notation □ Jumps directly to this square and stops, bypassing any intervening piece, but generally may not capture with this move with only a few exceptions. ☆ Jumps directly to this square and stops, bypassing any intervening piece, and may capture. ○ Steps a limited number of squares along a straight line, and may capture. Must stop upon capture. ○ Steps a limited number of squares along a straight line, capturing more than once. ● Steps a limited number of squares within an area, changing direction and capturing more than once. ╋ Steps a fixed number of squares within an area, changing direction and capturing more than once; cannot stop until range is exhausted. ☆ Jumps a limited number of times to this square; square may also be reachable with an areal step. ! igui (capture without moving). Counts for two steps. │ Ranges along a straight line, crossing any number of empty squares. Must stop upon capture. ─ ╲ ╱ ─ Ranges in this direction as well as immobilizes enemy pieces in the way. ╲ ╱ ! Shoots the nearest piece in this direction (capture without moving). ‼ Shoots twice in this direction (double capture without moving). * shoots at one of these squares, by passing any intervening piece (capture without moving). ※ Burns all adjacent enemy and allied pieces wherever it stops.

Unlike Western chess, a player need not move out of check, and indeed may even move into check. Although obviously not often a good idea, a player with more than one commanding piece (general or governor) may occasionally sacrifice one of these pieces as part of a gambit. 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. However, if the opponent's middle troop has promoted to governor 帥, and the player captures the general and banner, then the governor takes command in place of the general and the game continues until it too is captured. 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. A player who makes an illegal move loses immediately. (This rule may be relaxed in casual games.) Another possible, if rather uncommon, way for a game to end is repetition (sennichite). If the same position occurs four times with the same player to play, then the game is no contest. Recall, however, the prohibition against perpetual check.

The method used in English language texts to express shogi moves was established by George Hodges in 1976. It is derived from the algebraic notation used for chess, but differs in several respects. Modifications have been made for kō shogi. A typical example is P 8h. The first letter represents the piece moved (see above). Promoted pieces have a + added in front of the letter. (e. g., +MA for a governor (promoted middle troop). The designation of the piece is followed by a symbol indicating the type of move: for an ordinary move or x for a capture. Next is the designation for the intersection on which the piece lands. This consists of a number representing the file and a lowercase letter representing the rank, with 1a being the top right corner (as seen from Black's point of view) and 19s being the bottom left corner. (This method of designating intersections is based on Japanese convention, which, however, uses Japanese numerals instead of letters. For example, the intersection 2c is denoted by 2三 in Japanese.) 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 '!'. If a second or later capture is made, then it is added after the preceding capture. If a move entitles the player to promote the piece, then a + is added to the end to signify that the promotion was taken, or an = to indicate that it was declined. For example, MAx7c= indicates a middle troop capturing on 7c without promoting. In cases where the above notation would be ambiguous as to which piece is meant, the designation of the starting intersection is added after the designation for the piece. Moves are commonly numbered as in chess.