Chess puzzle (Crushing)
Opening: Sicilian_Defense, Sicilian_Defense_Sozin
Moves: 1. e4 c5 2. Nf3 d6 3. Bc4 Nc6 4. d4 cxd4 5. Nxd4 Nf6 6. Nc3 a6 7. Be3 e5 8. Nb3
b5 9. Bd3 Be6 10. Qd2 Be7 11. O-O-O O-O 12. f4 Bxb3 13. axb3 Qa5 14. Kb1 Rac8
15. f5 *
Position (FEN): 2r2rk1/4bppp/p1np1n2/qp2pP2/4P3/1PNBB3/1PPQ2PP/1K1R3R b - - 0 15
Black to move.
Themes:  Middlegame  
Puzzle rating: 1274
Best move: Nb4