Although more detailed information than this page provides is available elsewhere on the web, as well as in print, I still felt it worthwhile to briefly discuss a few of the best-known forms of Chess. I begin by giving the rules for the standard European game, although they are very well known, so as to have them available as a starting point in describing the other forms of Chess.
The board pictured at left is, of course, that for the standard European game of chess. The pieces for white, which always moves first, are at the bottom of the board. The array consists of one row of eight pawns in the front, and pieces in the order Rook, Knight, Bishop, Queen, King, Bishop, Knight, and Rook on the back rank.
Pawns move one space forwards, but may also move two spaces forwards on their first move. They do not capture in the normal direction of movement, but instead capture by moving one space diagonally forwards. A Pawn that reaches the opponent's back rank at the far side of the board must promote immediately, and may do so to a Queen, Rook, Bishop, or Knight. When a pawn moves two squares on its first move, on the next move, an opponent's pawn can move diagonally to the square it skipped over, capturing it as though it had only moved one space: this is en passant capture.
Rooks move and capture in a straight orthogonal line in any of the four cardinal directions, any number of spaces.
Bishops move and capture in a straight line in any diagonal direction, any number of spaces.
The Knight moves and captures so as to be displaced by two spaces in one orthogonal direction, and by one space in a perpendicular orthogonal direction. This move does not affect, nor is affected by, pieces that might seem to be intervening between its start and end.
The Queen moves and captures in the same ways as both the Rook and Bishop may do so, making either an orthogonal or diagonal move.
The King moves and captures one space in any orthogonal or diagonal direction. As its first move, if it is not threatened with capture, or crossing a space where it would be threatened with capture, it can move two spaces to the left or right, provided that no pieces intervene between it and the Rook on that side, which must also not have moved before, and which then leaps over it to the square it skipped over in its move. This is called castling.
The object of the game is checkmate, a situation where the King is liable to being captured in its present position (termed being in check) and no moves are possible except moves, whether by the King or by other pieces, that do not leave the King still liable to capture.
Stalemate, in which the King is not liable to capture in its present position, but would become so after any move that would otherwise be possible (otherwise, because it is illegal to move the King into check) is not a victory for the stalemating player, but is a draw.
The threefold repetition of the same position on the board allows the next player to claim a draw, and 50 moves without a capture or a Pawn advance allow either player to claim a draw (although this rule now has an exception in certain positions where a win has been shown to be possible, but to require more than 50 moves).
This is also the layout of Chaturanga, the original ancestor from India of the present game of chess. In it, the piece corresponding to the Bishop, called an Elephant, moved two squares diagonally, ignoring any piece on the intervening square, and the Queen moved only one space diagonally. Stalemate was a win for the stalemating player. Pawns promoted only to Queens, and there was no double-step first move.
The King also did not castle, but it had the privilege of making a Knight move once during the game, provided that it had not yet been checked. (This is the rule in the game of chess local to India played there at present; the rules for the original Chaturanga are not entirely known with certainty.)
The form of chess brought to Europe through Persia and the Arab world, Shatranj allowed the King to switch places with another piece on its side not en prise when stalemated.
Many variations of the rules of Chaturanga and Shatranj existed; for example, in some, stalemate was a loss for the stalemating player.
Malay chess, or Main Chator, had an unusual promotion rule: pieces reaching the end of the board, except on the Rook files, had then to move backwards to reach the main diagonal of the board before they promoted to the piece on that file (in the case of the King file, to a Queen). The Queen moved one space diagonally, the Bishop one space diagonally or one space forwards, as in Thai or Burmese chess. The rule for en passant capture only permits such a capture to be made by a Pawn blocked by a Pawn of the opposite color. The initial array is normally a reflection of that used in conventional Chess as well, the positions of the King and Queen on both sides being reversed.
There is also Mongolian chess, or Shatar, which was also played in Tibet.
In this game:
The Queen moves either as the Rook, or one space diagonally.
Only the King pawn can move two spaces on its first move.
Bare King is a draw.
Also, there are complicated rules on checkmate in this game:
The Knight can give check, but it cannot be the piece that gives checkmate. Either the Queen or Rook must be the piece by which the King is in check at the time of checkmate, or, in the series of moves leading to checkmate in which the King was in check continuously, one of those checks must have been given by the Queen, a Rook, or a Knight. Checkmate given otherwise is a draw, but (according to the account given of its rules by one web site) stalemate is a loss for the stalemated player.
Thai chess, called Makruk, starts with a different initial layout. The pawns do not move two spaces forwards on their first move, since they already start an extra space forwards. The Queen moves only one space diagonally (as a Fers), and the Bishop moves either one space diagonally or one space forwards (as an Elephant).
There is no castling, and of course no en passant capture. Pawns only promote to the Queen/Fers, and they do so on the rank at which the opponent's pawns are initially located, the sixth rank.
Stalemate is a draw. Incidentally, this traditional form of Thai chess continues to be popular throughout Thailand in the present day, and has not been overwhelmed by Western chess.
The Cambodian form of chess, Ok, is almost identical, but with a few added rules.
The King's first move, if it is not in check, can be a Knight's move, one square forwards and two squares to the left or right.
The Queen can move two spaces directly forwards as its first move as well.
These two additional moves were part of chess in Thailand in ancient times, but are no longer part of the game there.
When one player has a bare King, the number of moves the other player has to give checkmate is limited, based on the pieces the other player has available.
Normally, one subtracts the number of pieces on the board from 64 to give the number of moves allowed to give mate. But if no Pawns are left on the board, then the number of moves may be smaller depending on the forces available to the stronger player:
If the stronger player has only Queens, including promoted Pawns, and possibly only one Knight as well, or if there are (unpromoted) Pawns present, the starting point is 64 moves.
Burmese chess, or Sittuyin, also has the Queen moving only one space diagonally, and the Bishop moving either one space diagonally, or one space forwards.
Its most distinctive feature is that only the initial positions of the Pawns are fixed, the players disposing the other pieces at their own choosing.
In informal play, the players may simply both put their pieces on the board at the same time, or White may first place one piece, and then Black one piece, but in serious play, the official rule is that first White places all his pieces on the board, and then Black proceeds to set up his array, subject to not being allowed, except with the opponent's permission, to place both Rooks in the same column or a Rook in the same column as the opponent's King.
Placing one's opponent in stalemate is illegal. Pawns promote when they reach the diagonal lines in the opponent's half of the board.
Chinese chess, or Hsiang ch'i (Xiang Qi), is shown using Western chess symbols at right for ease of explanation.
The Pawn moves, and captures, forwards only until it crosses the middle line of the board, the river, after which it can move and capture sideways as well as forwards. It does not otherwise promote.
The Cannon moves as a Rook, but it captures along Rook lines as follows: it jumps over, without disturbing, the first man of either color on such a line, and then captures the next man on that line which must belong to the opponent.
The Rook (or Chariot) moves as in conventional chess.
The Knight (or Horse) moves almost as in conventional chess, except that its move consists of two steps, first an orthogonal move, and then a diagonal move involving only a 45-degree course change, and so it can be blocked by a piece on the intermediate square.
The piece shown as a Bishop (actually the Minister or Elephant, depending on which side it is on) moves always two squares diagonally, and can be blocked by an intervening piece. It cannot cross the river, but remains on its side of the board.
The piece shown as a Queen is the Counsellor, and moves one square diagonally; it cannot leave the nine-point area indicated by an X in the center of the back three rows of its own side.
The piece shown as a King is the General; it moves one step orthogonally only, and it, like the Minister, cannot leave the nine-point area indicated by the X. Also, the Generals of the two sides cannot face each other on an open file.
Stalemate is a win for the player that forces it, just as checkmate.
Because there are only five pawns, and they cannot protect each other, this game, although largely having the same pieces as the original Chaturanga, is very different from conventional Chess. Bringing the Chariots out early in the game, unwise in conventional Chess, is advisable in this game, for example.
Korean chess, Jang-gi, is played using the same board and men, except that the Generals are placed one square forwards compared to their initial position in Chinese chess.
In Korean chess, the Cannon jumps over one man to move as well as to capture. Also, the Generals and Counsellors both have the same move, and follow all the marked lines of the nine-point citadel.
Also, when in the citadel, the Chariot and Pawn both gain the power to move diagonally along those marked lines.
As well, when one side has fewer pieces than the other, due to captures, the General is allowed to give check by moving to a file where it faces the opposing General.
The Pawn and Counsellor are normally smaller, and the General larger, in a Korean chess set, in which the pieces are usually octagonal; in a Chinese chess set, the pieces are usually all the same size and circular.
Japanese chess, or Shogi, has as its main distinguishing feature the fact that captured pieces may be re-introduced on the board by the capturer. This feature is a relatively recent one, and was not present on the older versions of Shogi, such as Tsiu Shogi, played on a 12x12 board, or the other, larger versions, whose rules were once thought to have been lost, but which were recently rediscovered.
Re-entering a captured piece on the board counts as a move; a drop is expected to be an attacking move. Promoted pieces are re-entered in their unpromoted form. A Pawn may not be re-entered on a file containing one of one's own Pawns, and pieces that move only forwards cannot be re-entered in a position so advanced that they would be unable to move.
Also, while a dropped Pawn can give check, the drop of a Pawn cannot be the move that administers checkmate. This restriction does not apply to the drop of any other piece. Also, there is no restriction on blocking a check through interposition by means of a drop, and thus checkmate is often given by a protected piece adjacent to the King, since rendering it unprotected may relieve the mate but not the check, so the King would still be liable to capture on the next move.
Except for the King and the Gold General, all the pieces promote when they reach the last three rows of the board. Promotion is optional, except when the unpromoted piece would no longer be able to move, and can take place on any move that ends with the piece involved on the last three rows. The pieces are shown with their moves illustrated on them, and with the moves of their promoted forms in red below them.
The third row of pieces each player has consists of nine pawns; pawns promote to Gold General.
The second row consists of a Bishop on the player's left, and a Rook on the player's right. The Bishop promotes to Dragon Horse and the Rook to Dragon King, in each case adding the ability to move one square in the direction opposite to the normal movement of the piece.
The first row consists of Pikeman, Horse, Silver General, Gold General, King, Gold General, Silver General, Horse, and Pikeman.
Except for the King and the Gold General, all these pieces promote, and they promote to the Gold General.
The Pikeman can only move forwards on its file.
The Horse moves like a Knight, but can only make its two forwardmost moves.
The Silver General moves one space diagonally, or one space forwards.
The Gold General moves one space in any direction except diagonally backwards.
The King moves one space in any direction.
As with Chinese chess, the fact that the Pawns capture as they move changes the character of the game considerably from that of the conventional game of Chess; the ability to re-enter captured pieces changes it still further.
The immediate predecessor of the modern game of Shogi was Sho Shogi. In that game, there was one additional piece on the board, a Drunk Elephant, which was in the middle of the second row.
It could move in any direction except directly backwards; it promoted to a Crown Prince, which not only had the same move as the King, but which also had to be captured, in addition to the King, to defeat the side with a Crown Prince. In this form of the game, captured pieces were not returned to the board.