Figure[Black to move]

In the last two diagrams the Black pawn on h7 played an important role, taking away a crucial flight square for Black’s king. If h7 is open, merely hitting h8 and g8 with bishops won’t work; the king escapes. But then there is the alternative pictured here where Black again is mated. As before, White’s dark-squared bishop has a clean shot at h8. This time g8 again is sealed off by the light-squared bishop, but from a different angle; and h7 in turn is sealed off by a knight from g5, which also protects the bishop. The absence of pawns in front of the king gives it more flight squares and so requires three pieces to mate. (The general point: enemy flight squares require extra pieces.) This position is known as Blackburne’s mate, after the same player we encountered earlier in the chapter in the excerpt from the game Blackburne-Schwartz.