If, during the course of the game, it be discovered that any error or illegality has been committed in the moves of the pieces, the moves must be retraced, and the necessary correction made, without penalty.
For playing a man to a square to which it cannot be legally moved, the adversary, at his option, may require him to move the man legally, or to move the King.
For touching an adversary's man, when it cannot be captured, the offender must move his King.
In Castling, the King must be moved first, or before the Rook is quitted. If the Rook be quitted before the King is touched, the opposing player may demand that the move of the Rook shall stand without the Castling being completed.
The Bishop moves diagonally forwards or backwards, to the extent of the Board.
The Pawn moves only one square at a time, and that straight forward, except in the act of capturing, when it takes one step diagonally to the right or left file on to the square occupied by the man taken, and continues on that file until it captures another man.