In chess, promotion is the replacement of a pawn with a new piece when the pawn is moved to its last . The player replaces the pawn immediately with a queen, rook, bishop, or knight of the same . The new piece does not have to be a previously captured piece. Promotion is mandatory; the pawn cannot remain as a pawn. Promotion to a queen is known as queening; promotion to any other piece is known as underpromotion. Promotion is almost always to a queen, as it is the most powerful piece. Underpromotion might be done for various reasons, such as to avoid stalemate or for tactical reasons related to the knight's unique movement pattern. Promotion or the threat of it often decides the result in an endgame. Rules When a pawn is promoted, it is removed from the board, and the new piece is placed on the square of promotion. A piece may be promoted to regardless of whether it has been captured. Consequently, a player might have two or more queens, or three or more rooks, bishops, or knights. In theory, a player could have as many as nine queens, ten knights, ten bishops, or ten rooks, though these are highly improbable scenarios. Representation of promoted pieces Most chess sets come with only the 32 pieces used in the starting position. Some chess sets come with an extra queen of each color, but this does not accommodate the possibility of having three or more pieces of the same type. When multiple sets are available, promoted pieces are borrowed from other sets if required. Under FIDE rules, a player may stop the clocks and summon the arbiter to provide a piece for promotion. Under US Chess Federation rules and in casual play, an upside-down rook may designate a queen. However, according to FIDE arbiter guidelines, such a move is treated as a legal promotion to a rook (not an illegal move, which would incur a time penalty). History Promotion first existed in chaturanga, an ancestor of chess created in the 6th century. In chaturanga, a pawn is promoted upon reaching the last rank of the board. Historians dispute what the pawn can be promoted to. Some sources state that a pawn can be promoted only to a mantri, an early form of the queen only able to move one square diagonally, with the idea being that a foot soldier