Any rook move will threaten Bd7 mate; Black's only defence is to stick his queen in the way on g4, when 2. Rxg4 hxg4 3. Bxg4 renews the threat of mate, and nothing can stop it. But Black does not have to recapture. After, for example, 1.Rxf4 Qg4 2. Rxg4, he plays 2 . . . Ra2] when even 3. Rg2 Rxb2] 4. Rxb2 c3 wins for Black. Let's start again.
What about taking the queen with the bishop? Rook somewhere, Qg4, Bxg4, hxg4 and now bxa3 loses to c3, so White needs another threat.
Unless you have become fixated on the a4-d7 diagonal (an easy thing to do) you should now notice the possibility of mate from another direction. 1. Rg1] Qg4 2. Bxg4 hxg4 3. Rc1] and Black must play c3. You should now get the idea: 4. Rd1 d3 5. Re1 e3 6. Rf1 f3 7. Rg1 g3 8. Rh1 h3 9. Rxh3 and mate next move with Rh4.Reuse content