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.

When a Piece or Pawn is in a situation to be taken by the enemy, it is said to be en prise. To put a piece en prise, is to play it so that it may be captured.

The Chess-board must be placed with a white square at the right-hand corner.

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.

The Queen is usually reckoned equal, in average situations, to two Rooks and a Pawn, but towards the end of a game she is hardly so valuable as two Rooks.

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.