What Black pieces are loose? Just the rook at c6, so White looks for ways to attack it while giving check or threatening mate. Qe4 seems awfully close to working; it attacks the rook and, along with White’s knight, threatens h7 for a second time. The hitch is that Black’s queen also protects h7, and White has no way to drive the queen off. Once White sees that only the Black queen stops the winning fork, he focuses on how he might get rid of it—perhaps by harrying it with his pawns. White starts his kingside pawns forward with a threat against Black's knight: h2-h3. Where would the knight go? It turns out to have only one safe square: h6. Ah! The knight then would block the Black queen’s route to h7. Suddenly there is no need to drive off the queen after all; now White's Qe4 would create a serious mating threat because Black’s queen wouldn't be able to help, and the rook at c6 remains loose. So: 1. h2-h3, Nh6; 2. Qe4 wins the rook. (Black would be better off just forfeiting the knight.) The hardest part about this one is seeing that Black's knight would have to go to h6. Remember that a threatened knight often has limited options, and that when it is forced to a new square there may be interesting side effects.