Chess puzzle (Advantage)
Moves: 1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4 d6 5. c3 Nf6 6. Bg5 Be7 7. cxd4 Nxe4 8.
Bxe7 Qxe7 9. O-O Bg4 10. Re1 O-O-O 11. Nc3 f5 12. Qd3 Bxf3 13. Qxf3 Qf6 14. Nd5
Qg6 15. Bb5 Rhe8 16. Rac1 Nxd4 17. Rxc7+ Kb8 18. Qd3 Nxb5 19. Qxb5 Nc5 20. Rc1
Qe6 21. Rxb7+ *
Position (FEN): 1k1rr3/pR4pp/3pq3/1QnN1p2/8/8/PP3PPP/2R3K1 b - - 0 21
Black to move.
Themes:  Middlegame  
Puzzle rating: 851
Best move: Nxb7