Tuesday, December 12, 2006

Rules of chess

For a simple demonstration of the gameplay, see sample chess game.
Name Letter Picture
Pawn P PawnPawn
Knight N KnightKnight
Bishop B BishopBishop
Rook R RookRook
Queen Q QueenQueen
King K KingKing

Chess is played on a square board of eight rows (called ranks and denoted with numbers 1 to 8) and eight columns (called files and denoted with letters a to h) of squares. The colors of the sixty-four squares alternate between light and dark, and are referred to as "light squares" and "dark squares". The chessboard is placed so that each player has a white square in the near right hand corner, and the pieces are set out as shown in the diagram, with each queen on a square that matches its color.

Each player begins the game with sixteen pieces: each player's pieces comprise one king, one queen, two rooks, two bishops, two knights and eight pawns. One player, referred to as White, controls the white pieces and the other player, Black, controls the black pieces; White is always the first player to move. The colors are chosen either by a friendly agreement, by a game of chance or by a tournament director. The players alternate moving one piece at a time (with the exception of castling, when two pieces are moved at the same time). Pieces are moved to either an unoccupied square, or one occupied by an opponent's piece, capturing it. With one exception (en passant), all pieces capture opponent's pieces by moving to the square that the opponent's piece occupies.

When a king is under direct attack by one (or possibly two) of the opponent's pieces, the player is said to be in check. When in check, only moves that remove the king from attack are permitted. The player must not make any move that would place his king in check. The object of the game is to checkmate the opponent; this occurs when the opponent's king is in check, and there are no moves that remove the king from attack.

Image:chess_zhor_22.png
Image:chess_zver_22.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Image:chess_zver_22.png
Image:chess_zhor_22.png
Moves of a king; positions after kingside (White) and queenside (Black) castling
Image:chess_zhor_22.png
Image:chess_zver_22.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Image:chess_zver_22.png
Image:chess_zhor_22.png
Moves of a rook
Image:chess_zhor_22.png
Image:chess_zver_22.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Image:chess_zver_22.png
Image:chess_zhor_22.png
Moves of a bishop
Image:chess_zhor_22.png
Image:chess_zver_22.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Image:chess_zver_22.png
Image:chess_zhor_22.png
Moves of a queen
Image:chess_zhor_22.png
Image:chess_zver_22.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Image:chess_zver_22.png
Image:chess_zhor_22.png
Moves of a knight
Image:chess_zhor_22.png
Image:chess_zver_22.png
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Image:chess_zver_22.png
Image:chess_zhor_22.png
Moves of a pawn; Pc6 can move to c7 or take one of black pieces; Ph5 can take en passant the black Pg5 if the last Black move was g7-g5

Each kind of chess piece moves a different way.

  • The king can move only one square horizontally, vertically, or diagonally. Once in the game, each king is allowed to make a special double move, to castle. Castling consists of moving the king two squares towards a rook, then moving the rook onto the square over which the king crossed. Castling is only permissible if all of the following conditions hold:
  1. The player must never have moved both the king and 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 squares that are under attack by enemy pieces. As with any move, castling is illegal if it would place the king in check.
  4. The king and the rook must be on the same rank (to exclude castling with a promoted pawn).
  • The rook moves any number of vacant squares vertically or horizontally (it is also involved in the king's special move of castling);
  • The bishop moves any number of vacant squares in any direction diagonally. Note that a bishop never changes square color, therefore players speak about "light-squared" or "dark-squared" bishops;
  • The queen can move any number of vacant squares diagonally, horizontally, or vertically;
  • The knight can jump over occupied squares and moves two spaces horizontally and one space vertically or vice versa, making an "L" shape. A knight in the middle of the board has eight squares to which it can move. Note that every time a knight moves, it changes square color.
  • Pawns have the most complex rules of movement:
  • A pawn can move forward one square, if that square is unoccupied. If it has not moved yet, the pawn has the option of moving two squares forward, if 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 than 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. In practice, the pawn is almost always promoted to a queen.

With the exception of the knight, pieces cannot jump over each other. One's own pieces ("friendly pieces") cannot be passed if they are in the line of movement, and a friendly piece can never replace another friendly piece. Enemy pieces cannot be passed, but they can be "captured". 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.[1] The king cannot be captured, only put in check. If a player is unable to get the king out of check, checkmate results, with the loss of the game.

Chess games do not have to end in checkmate — either player may resign if the situation looks hopeless. Games also may end in a draw (tie). A draw can occur in several situations, including draw by agreement, stalemate, threefold repetition of a position, the fifty move rule, or a draw by impossibility of checkmate (usually because of insufficient material to checkmate).

Besides casual games without exact timing, chess is also played with a time control, mostly by club and professional players. The timing ranges from long games played up to seven hours to shorter rapid chess games lasting usually 30 minutes or one hour per game. Even shorter is blitz chess with a time control of three to fifteen minutes for each player and bullet chess (under three minutes). If the player's time runs out, he loses.

The international rules of chess are described in more detail in the FIDE Handbook, section Laws of Chess.[2]

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