White to play
Answer:
1. Rxg7+! Kh8
(If you played 2. Rg3+ you had the right idea, but too early, after 2… f6 black avoids checkmate and has a winning endgame)
2. Rxf7+ Kg8
(One of Mikhail Tal’s principles to attacking: Destroy the fortress walls!)
3. Rg7+ Kh8
4. Rg3+ Nd4
5. Bxd4+ Rf6
6. Bxf6#