Chess is a two-player board game utilizing a chessboard and sixteen pieces of six types for each player. Each type of piece moves in a distinct way. The goal of the game is to checkmate (threaten with inescapable capture) the opponent’s king. Games do not necessarily end in checkmate; players often resign if they believe they will lose. A game can also end in a draw in several ways.
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.
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.
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 (en passant is the only exception). The captured piece is thereby permanently removed from the game. 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 in a horizontal or vertical direction. It also is moved when castling.
A bishop moves any number of vacant squares in any diagonal direction.
The queen moves any number of vacant squares in a horizontal, vertical, or diagonal direction.
A knight moves to the nearest square 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.
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.
Pawns are the only pieces that capture differently from how they move. A pawn can capture an enemy piece on either of the two squares diagonally in front of the pawn (but cannot move to those squares if they are vacant).