What is Wrong Rook Pawn?

Wrong Rook Pawn is a term used in chess to describe a situation in which the pawn that remains in play is a rook pawn (a pawn on either the 'a' or 'h' file) and its promotion square is the 'wrong color' in relation to the bishop that the player has. This means that the bishop is not able to control the square on which the pawn would be promoted. In such a situation, a King and Bishop cannot force the pawn to be promoted if the opponent's King reaches the promotion square. It's called 'wrong’ because under certain circumstances it cannot help to achieve a win.