Chess is one of the oldest and most popular board games. It is played by two opponents on a checkered board with specially designed pieces of contrasting colours, commonly white and black. The objective of the game is to capture the opponent's king.
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 except in the case of en passant. 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 horizontally or vertically. It also is moved when castling.
- A bishop moves any number of vacant squares diagonally.
- 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
- 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.