White has several pieces bearing down on the Black king’s general position—a queen trained on h7, a rook on the sixth rank, another rook on the f-file, and a knight nearby as well. Focus on that last piece: when you have a knight near the enemy king, the search for forks should be automatic; all those other pieces nearby are important in part because they can be used as tools to help make a fork work. In this case you see that White’s knight has a forking square in f6. The trouble is that the needed square is protected by the pawn on g7. White has no way to take the pawn, and it doesn’t protect any pieces White can take, either. But it does protect sensitive squares near Black’s king, so putting an attacker on one of those squares may be as good as taking a piece the pawn protects. Here White sees that since his queen already attacks h7, adding another attacker against that square would create a mate threat. (This is a common formula: if your queen attacks a square adjacent to the enemy king, adding another attacker against the same square often creates a threat of mate.) Thus White plays Rh6. The rook now provides the cover White needs to play Qxh7# next move. To prevent this Black has to play g7xR—and now the f6 square is available for White’s knight. He plays Nf6+, and after NxQ next move White has won a queen for a rook.

We see again the power of combining our knowledge of the knight fork with a close look at your mating threats against the enemy king.