White has his queen and f-pawn arranged for Lolli’s mate. But since Black’s rook is on g8, White would have to use the sequence where he sacrifices his queen on h7—and he has no rook in position to then follow up on the h-file. What to do? There are two helpful thoughts available. One is to pin the bothersome rook with Rb8 so that Black can't play RxQg7. Another is to bring the e5 knight into the fray with Nxf7+—almost mate, since Black’s king has no flight squares. Both these ideas are frustrated by Black’s queen on a7, which guards b8 (where White’s rook wants to go) and f7 (where White’s knight wants to go). But these problems will suggest their own solution if you have studied the chapter on the overworked piece: the queen can't defend against both threats, so play one and then the other. White starts with Rb8, and mates with Qg7 next move if Black doesn’t play QxR. Yet if Black’s queen does make that capture, it abandons f7 to White’s knight and mate results anyway.

The first lesson of this position is a reminder to think flexibly about how you might substitute for missing ingredients when you work with a mating pattern. As we will see in detail soon, a knight often can do the same work performed by bishops and rooks in the mates studied so far. A second lesson is the importance of combining these basic mating principles with all that you have learned elsewhere about other tactical tools. If you find a mating pattern close to completion but impeded by an enemy piece, consider pinning the piece; consider forking it; consider taking something else it protects; etc. Finally, consider this a study in the value of seeing and taking seriously ideas that don’t quite work. If you understand why they don’t work, the reasoning may lead you to something that does. Here neither Rb8 nor Nxf7 quite works; but once you understand why, you see that together they are too much for Black.