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Chess
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Logical multi-game |
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"Rules"
The board is placed so that a white square is in the near-right corner, and a black one in the near-left. Each player controls sixteen pieces:
1 king
1 queen
2 rooks
2 bishops
2 knights
8 pawns |
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At the beginning of the game, the pieces are arranged as shown in the diagram to the right.
* The second row from the player contains the eight pawns.
* The row nearest the player contains the remaining pieces:
The rooks are placed on the outside corners.
The knights are placed immediately inside of the rooks.
The bishops are placed immediately inside of the knights.
The queen is placed on the central square of the same color of that of the player:
white queen on the white square and black queen on the black square.
The king takes the vacant spot next to the queen.
Popular phrases used to remember the set-up, often heard in beginners' clubs, are "queen on color" and "white on right". The latter refers to setting up the board so that the square closest to each player's right is white.
To describe moves and locations on the board, a chess notation is used. Algebraic chess notation is now the standard, but there are other systems such as the obsolete descriptive chess notation.
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Starting position
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a b c d e f g h
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"Gameplay"
Each player has control of one of the two sets of colored pieces and are typically referred to by the nominal color of their respective pieces, i.e., White or Black. White moves first and, as in most board games, the players alternate moves. Play continues until a draw is declared, a player resigns, or a king is checkmated, as explained below.
Unlike Go, where the order of play is determined by the relative skills and handicaps of the players, the official chess rules do not include a procedure for determining who plays White. Instead, this decision is left open to tournament-specific rules (e.g. a Swiss system tournament or Round-robin tournament) or, in the case of non-competitive play, mutual agreement, in which case some kind of random choice is often employed. |
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Moves of a king
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"Movement"
Each chess piece has its own style of moving. Moves are made to vacant squares except when capturing an opponent's piece.
With the exception of the knight, pieces cannot jump over each other. When a piece is captured (or taken), the attacking piece replaces the enemy piece on its square (en passant being the only exception). The captured piece is thus removed from the game and may not be returned to play for the remainder of the game. The king cannot be captured, only put in check. |
Moves of a rook
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Moves of a bishop
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Moves of a queen
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Moves of a knight
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Moves of a pawn
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The white pawns can move to the squares marked with "X" in front of them. The pawn on c6 can also take either black rook. The pawn on h5 can also take en passant the black pawn on g5 if the last Black move was g7-g5, which will result on the white pawn going to g6 (the dot).
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The king can move exactly one square horizontally, vertically, or diagonally. At most once in every game, each king is allowed to make a special move, known as castling. Castling consists of moving the king two squares towards a rook, then placing the rook on the other side of the king, adjacent to it. Castling is only permissible if all of the following conditions hold:
1. The player must never have moved either the king or the rook involved in castling;
2. There must be no pieces between the king and the rook;
3. The king may not currently be in check, nor may the king pass through or end up in a square that is under attack by one or more enemy pieces (though the rook is permitted to be under attack);
4. The king and the rook must be on the same rank (to exclude castling with a rook from a promoted pawn).
In serious play, the king must be touched and moved first when castling; its move of more than one square makes clear that castling is intended.
The rook moves any number of vacant squares vertically or horizontally. It also is moved while castling.
The bishop moves any number of vacant squares in any diagonal direction.
The queen can move any number of vacant squares diagonally, horizontally, or vertically.
The knight moves to the nearest square not on the same rank, file, or diagonal. Equivalently, the knight moves two squares like the rook and then one square perpendicular to that. Its move is not blocked by other pieces, i.e. it leaps to the new square.
Pawns have the most complex rules of movement:
A pawn can move forward one square, if that square is unoccupied. If it has not yet moved, the pawn has the option of moving two squares forward provided both squares in front of the pawn are unoccupied. A pawn cannot move backward.
When such an initial two square advance is made that puts that pawn horizontally adjacent to an opponent's pawn, the opponent's pawn can capture that pawn "en passant" as if it moved forward only one square rather than two, but only on the immediately subsequent move.
Pawns are the only pieces that capture differently from how they move. They can capture an enemy piece on either of the two spaces adjacent to the space in front of them (i.e., the two squares diagonally in front of them), but cannot move to these spaces if they are vacant.
If a pawn advances all the way to its eighth rank, it is then promoted (converted) to a queen, rook, bishop, or knight of the same color, the choice being at the discretion of its player. In practice, the pawn is almost always promoted to a queen. If it converted to another piece, this is called "underpromotion".
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Check and checkmate
When a player makes a move that threatens the opposing king with capture (not necessarily by the piece that was moved), the king is said to be in check. If a player's king is in check then the player must make a move that eliminates the threat of capture; a player may never leave his king in check at the end of his move. The possible ways to remove the threat of capture are:
Move the king to a square where it is not threatened.
Capture the threatening piece (possibly with the king, if doing so does not put the king in check).
Place a piece between the king and the opponent's threatening piece (not possible if the threatening piece is a knight).
In informal games, it is customary to announce check when making a move that puts the opponent's king in check. However, in formal competitions check is rarely announced.
A player may not make any move which places or leaves his king in check. (This also entails that a player cannot place his king on any square adjacent to the enemy king, because doing so would leave his king able to be taken by the enemy king and therefore in check.)
If a player's king is placed in check and there is no legal move that player can make to escape check, then the king is said to be checkmated, the game ends, and that player loses (unlike other pieces, the king is never actually captured or removed from the board). The diagram to the right shows a typical checkmate position.
The white king is threatened by the black queen; every square to which the king could move is also threatened; and he cannot capture the queen, because he would then be threatened by the rook.
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"DRAWS"
The game ends in a draw in any of these conditions occur:
The game is automatically a draw if the player to move is not in check but has no legal move.
This situation is called a stalemate. An example of such a position is shown in the diagram to the right.
There is no possibility for either player to checkmate the opponent. For example one player has a king and a knight and another only a king.
Both players agree to a draw (Draw by agreement).
Either player may claim a draw by indicating that one of the following conditions exists:
Fifty moves have been played by each player without a piece being captured or a pawn moved.
The same board position has been repeated three times, with the same player to move and all pieces having the same rights to move, including the right to castle or capture en passant.
If the claim is proven true, the game is drawn.
At one time, if a player was able to check the opposing king continually (perpetual check) and he indicated his intention to do so, the game was drawn. This rule is no longer in effect; however, players will usually agree to a draw in such a situation, since either the threefold repetition rule or the fifty move rule will eventually be applicable.
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"Resigning"
Either player may resign at any time; this normally happens when the player believes he is certain to lose the game. This typically arises because:
he can foresee an unavoidable checkmate a few moves ahead, or
he is at or can foresee a decisive material disadvantage - e.g. he has lost or is about to lose a major piece, or the opponent is about to promote a pawn.
In master play, it is much more common for a game to be resigned than for it to end with checkmate, because players can foresee checkmate well in advance.
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