Chess piece
A chess piece, or chessman, is a game piece that is placed on a chessboard to play the game of chess. It can be either white or black, and it can be one of six types: king, queen, rook, bishop, knight, or pawn. Chess sets generally come with sixteen pieces of each color. Additional pieces, usually an extra queen per color, may be provided for use in promotion. Number of pieces. Each player begins with sixteen pieces (but see the subsection below for other usage of the term "piece"). 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 as "White", whereas the darker colored pieces are referred to as "black" and the player that owns them as "Black". In a standard game, each of the two players begins with the following sixteen pieces: Usage of the term "piece". The word "piece" has three meanings, depending on the context. Moves of the pieces. The rules of chess prescribe the moves each type of chess piece can make. During play, the players take turns moving their own chess pieces. Pieces other than pawns  capture in the same way that they move. A capturing piece replaces the opponent piece on its square, except for an "en passant" capture by a pawn. 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. For example, in an , bishops are  relatively more valuable; they can be positioned to control long, open diagonal spaces. In a with lines of protected pawns blocking bishops, however, knights usually become relatively more potent. 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 depending on the position or the phase of the game (opening, middle game , or ending). A for example, is worth an additional half-pawn on average. In specific circumstances, the values may be quite different: sometimes a knight can be more valuable than a queen if a particular angle is required for a mating attack, such as certain smothered mates. The humble pawn becomes more and more valuable the closer it is to securing a queen promotion for another example. History. Chess evolved over time from its earliest versions in India and Persia to variants that spread both West and East. Pieces changed names and rules as well; the most notable changes was  the Vizir (or Firz) becoming the Queen, and the Elephant becoming the Bishop in European versions of chess. The movement patterns for Queens and Bishops also changed, with the earliest rules restricting elephants to just two squares along a diagonal, but allowing them to "jump" (seen in the fairy chess piece the alfil); and the earliest versions of queens could only move a single square diagonally (the fairy chess piece Ferz). The modern bishop's movement was popularized in the 14th and 15th centuries, and the modern queen was popularized in the 15th and 16th centuries, with versions with the  more powerful modern queen eclipsing older variants. 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" in language areas that adapted the modern bishop's movement pattern, but not its new name. Variant pieces. Chess variants sometimes include new, non-standard, or even old pieces. For example, Courier Chess, a predecessor of modern chess dating from the 12th century, was played on an 8x12 board and used all six modern chess piece types , plus three additional types of pieces: Courier, Mann (or "rath" or "sage"), and Jester. Variants of "old" chess might use the old rules for bishops/elephants with the alfil piece, or old rules for Queens with the ferz. Many modern variants with unorthdox pieces exist, such as Berolina chess which uses custom pawns that advance diagonally and capture vertically.