No. 8.
BLACK.
WHITE.
In this situation the white King is threatened with what is called "a discovered check," that is, his opponent, by removing the Bishop, would discover check from the Queen, a proceeding in the present instance, which would speedily involve the loss of the game to White. Not being at the moment in check, however, and having moved neither King nor Rook, and there being no intervening Piece between the King and his own Rook, White is enabled to castle, giving check to the adverse King at the same time, and win the game easily, for Black has no square to which he can move his King without going into check, and is consequently obliged to interpose his Q. at K. B's second, or K. B's third square, in either case being checkmated in two more moves, as you will soon be able to see.
Checkmate.
No. 9.
BLACK.
WHITE.