Shogi "generals' chess", or Japanese chess , is the most popular of a family of chess variants native to Japan. Unique to shogi among the games of the chess family are drops, moves whereby captured enemy pieces are returned into play as ally pieces.
Two players, Black and White (or sente and gote ), play on a board composed of squares (actually rectangles) in a grid of 9 ranks (rows) by 9 files (columns). The squares are undifferentiated by marking or colour.
Each player has a set of 20 wedge-shaped pieces of slightly different sizes. Except for the kings, opposing pieces are differentiated only by orientation, not by marking or color. From largest to smallest (most to least powerful), the pieces are:
Each player places his pieces in the positions shown below, facing the opponent.
In the rank nearest the player:
- The king is placed in the center file.
- The two gold generals are placed in the adjacent files to the king.
- The two silver generals are placed adjacent to each gold general.
- The two knights are placed adjacent to each silver general.
- The two lances are placed in the corners, adjacent to each knight.
That is, the first rank is |L|N|S|G|K|G|S|N|L|.
In the second rank, each player places:
- The bishop in the same file as the left knight.
- The rook in the same file as the right knight.
In the third rank, the nine pawns are placed one to each file.
Traditionally, even the order of placing the pieces on the board is determined. There are two recognized orders, ohashi and ito. The Japanese-language page Shogi Pineapple indicates the two orders; ohashi is depicted on the left and ito on the right.
The two players take command of pieces on either side of the river. One player's pieces are usually painted red (or, less commonly, white), and the other player's pieces are usually painted black (or, less commonly, blue or green). Which player moves first has varied throughout history, and also varies from one part to another of China. Some xiangqi books state that the black side moves first; others state that the red side moves first. Also, some books may refer to the two sides as north and south; which direction corresponds to which color also varies from source to source. Generally, red goes first in most modern formal tournaments.
A King can move one square in any direction, orthogonal or diagonal.
A rook can move any number of free squares along any one of the four orthogonal directions.
A bishop can move any number of free squares along any one of the four diagonal directions.
Because they cannot move orthogonally, the opposing unpromoted bishops can only reach half the squares of the board.
A gold general can move one square orthogonally, or one square diagonally forward, giving it six possible destinations. It cannot move diagonally backward.
A silver general can move one square diagonally or one square directly forward, giving it five possibilities.
Because an unpromoted silver can retreat more easily than a promoted one (see below), it is very common to leave a silver unpromoted at the far side of the board.
A knight jumps at an angle intermediate between orthogonal and diagonal, amounting to one square forward plus one square diagonally forward, in a single motion. That is, it has a choice of two forward destinations. It cannot move to the sides or backwards.
The knight is the only piece that ignores intervening pieces on the way to its destination. It is not blocked from moving if the square in front of it is occupied, but neither can it capture a piece on that square.
It is often useful to leave a knight unpromoted (see below) at the far side of the board. However, since a knight cannot move backward or to the sides, it must promote when it lands on one of the two far ranks and would otherwise be unable to move further.
A lance can move any number of free squares directly forward. It cannot move backward or to the sides.
It is often useful to leave a lance unpromoted (see below) at the far side of the board. However, since a lance cannot move backward or to the sides, it must promote if it arrives at the far rank.
A pawn can move one square directly forward. It cannot retreat.
Since a pawn cannot move backward or to the sides, it must promote (see below) if it arrives at the far rank. However, in practice, a pawn is promoted whenever possible.
Unlike the pawns of international chess, shogi pawns capture the same way they otherwise move, directly forward.
A promoted rook (dragon king) may move as a rook or as a king, but not as both on the same turn.
A promoted bishop ("horse") may move as a bishop or as a king, but not as both on the same turn.