The rules of chess (also known as the laws of chess) govern the play of the game of chess. Chess is a two-player abstract strategy board game. Each player controls sixteen pieces of six types on a chessboard. Each type of piece moves in a distinct way. The object of the game is to checkmate the opponent's king; checkmate occurs when a king is threatened with capture and has no escape. A game can end in various ways besides checkmate: a player can resign, and there are several ways a game can end in a draw.
While the exact origins of chess are unclear, modern rules first took form during the Middle Ages. The rules continued to be slightly modified until the early 19th century, when they reached essentially their current form. The rules also varied somewhat from region to region. Today, the standard rules are set by FIDE (Fédération Internationale des Échecs), the international governing body for chess. Slight modifications are made by some national organizations for their own purposes. There are variations of the rules for fast chess, correspondence chess, online chess, and Chess960.
Besides the basic moves of the pieces, rules also govern the equipment used, time control, conduct and ethics of players, accommodations for physically challenged players, and recording of moves using chess notation. Procedures for resolving irregularities that can occur during a game are provided as well.
Basic moves
The pawns can move to the squares marked "×" in front of them. The pawn on c6 can also take either black rook.
Each type of chess piece has its own method of movement. A piece moves to a vacant square except when capturing an opponent's piece.[8]
Except for any move of the knight and castling, pieces cannot jump over other pieces. A piece is captured (or taken) when an attacking enemy piece replaces it on its square. The captured piece is thereby permanently removed from the game.[a] The king can be put in check but cannot be captured (see below).
The king moves exactly one square horizontally, vertically, or diagonally. A special move with the king known as castling is allowed only once per player, per game (see below).
A rook moves any number of vacant squares horizontally or vertically. It also is moved when castling.
A bishop moves any number of vacant squares diagonally. (Thus a bishop can move to only light or dark squares, not both.)
The queen moves any number of vacant squares horizontally, vertically, or diagonally.
A knight moves to one of the nearest squares not on the same rank, file, or diagonal. (This can be thought of as moving two squares horizontally then one square vertically, or moving one square horizontally then two squares vertically—i.e. in an "L" pattern.) The knight is not blocked by other pieces; it jumps to the new location.
Pawns have the most complex rules of movement:
A pawn moves straight forward one square, if that square is vacant. If it has not yet moved, a pawn also has the option of moving two squares straight forward, provided both squares are vacant. Pawns cannot move backwards.
A pawn, unlike other pieces, captures differently from how it moves. A pawn can capture an enemy piece on either of the two squares diagonally in front of the pawn. It cannot move to those squares when vacant except when capturing en passant.
The pawn is also involved in the two special moves en passant and promotion.[10]