A chess piece, or chessman, is any of the six different types of movable objects used on a chessboard to play the game of chess.
Number of pieces
Each player begins with a total of sixteen pieces. The pieces that belong to each player are distinguished by color. The lighter colored pieces are referred to as "white," and the player that owns them, "White". The darker colored pieces are referred to as "black", and the player that owns them, "Black". The word "piece" has three meanings, depending on the context. Context should make the intended meaning clear .
It may mean any of the physical pieces of the set, including the pawns. When used this way, "piece" is synonymous with "chessman" or simply "man". Chess sets have been made in a variety of styles, sometimes for decorative or artistic purposes rather than practical play, but the Staunton pattern is standard for competition.
In play, the term is usually used to exclude pawns, referring only to a queen, rook, bishop, knight, or king. In this context, the pieces can be broken down into three groups: , , and the king.
In phrases such as "winning a piece", "losing a piece" or "sacrificing a piece" and other related contexts, it refers only to minor pieces. The queen, rook, and pawn are specified by name in these cases—for example, "winning a queen", "losing a rook", or "sacrificing a pawn".
In the first context, each of the two players begins with the following sixteen pieces in a standard game:
The rules of chess prescribe the types of move a player can make with each type of chess piece. Each piece type moves in a different way. During play, the players take turns moving one of their own chess pieces.
The rook moves any number of vacant squares forwards, backwards, left, or right in a straight line. It also takes part, along with the king, in a special move called castling.
The bishop moves any number of vacant squares diagonally in a straight line. Consequently, a bishop stays on squares of the same color throughout a game. The two bishops each player starts with move on squares of opposite colors.
The queen moves any number of vacant squares in any direction: forwards, backwards, left, right, or diagonally, in a straight line.
The king moves exactly one vacant square in any direction: forwards, backwards, left, right, or diagonally; however, it cannot move to a square that is under attack by an opponent, nor can a player make a move with another piece if it will leave the king in check. It also has a special move called castling, in which the king moves two squares towards one of its own rooks and in the same move, the rook jumps over the king to land on the square on the king's other side. Castling may only be performed if the king and rook involved have never previously been moved in the game, if the king is not in check, if the king would not travel through or into check, and if there are no pieces between the rook and the king.
The knight moves on an extended diagonal from one corner of any 2×3 rectangle of squares to the furthest opposite corner. Consequently, the knight alternates its square color each time it moves. Other than the castling move described above where the rook jumps over the king, the knight is the only piece permitted to routinely jump over any intervening piece when moving.
The pawn moves forward exactly one square, or optionally, two squares when on its starting square, toward the opponent's side of the board. When there is an enemy piece one square diagonally ahead of a pawn, either left or right, then the pawn may capture that piece. A pawn can perform a special type of capture of an enemy pawn called en passant. If the pawn reaches a square on the of the opponent, it promotes to the player's choice of a queen, rook, bishop, or knight.
Pieces other than pawns capture in the same way that they move, except for castling. A capturing piece replaces the opponent piece on its square, except for an en passant capture. Captured pieces are immediately removed from the game. A square may hold only one piece at any given time. Except for castling and the knight's move, no piece may jump over another piece.
Relative value
The value assigned to a piece attempts to represent the potential strength of the piece in the game. As the game develops, the relative values of the pieces will also change. A bishop positioned to control long, open diagonal spaces is usually more valuable than a knight stuck in a corner. Similar ideas apply to placing rooks on open files and knights on active,. The standard valuation is one point for a pawn, three points for a knight or bishop, five points for a rook, and nine points for a queen. These values are reliable in endgames, particularly with a limited number of pieces. But these values can change dramatically depending on the position, the phase of the game. A for example, is worth a half a pawn on average. In specific circumstances, the values may be quite different: a knight can be more valuable than a queen in a particular decisive attack.
Historical illustration
, a predecessor of modern chess, used all six chess piece types plus a courier, man, and jester.
Piece names
The characters implied by pieces' names vary between languages. For example, in many languages, the piece known in English as the "knight" frequently translates as "horse", and the English "bishop" frequently translates as "elephant".
