It is the only piece which can jump over obstructing pieces. When a player moves his piece into a square occupied by an opponent piece, he can capture and remove it from the board at once. In diagrams the pieces in hand are shown beside the board. Promotion is optional and at any given time the option may only be exercised on that move. However, the right to promote arises every time he moves the piece in the opponent's camp until the promotion is made.
Promotion is done by turning over the piece immediately upon completion of the move.
Promoted pieces cannot be reversed again. A piece can be dropped only in its unpromoted state, even if it was promoted when captured. Once dropped, the player can use the piece just like the others already on the board. A move is completed when the player has taken his hand off the piece. Except in rare cases, a King is not actually taken.