Chess puzzle (Advantage)
Moves: 1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 e5 5. Nb5 a6 6. Nd6+ Bxd6 7. Qxd6 Qf6 8.
Qc5 d6 9. Qb6 Nge7 10. Nc3 O-O 11. Be3 Rb8 12. O-O-O Bd7 13. Nd5 Nxd5 14. Rxd5
Rfc8 15. Bc4 Qg6 16. Rhd1 Qxe4 17. Rxd6 Qxc4 18. Rxd7 h6 19. Rxb7 Rxb7 20. Qxb7
Nb4 21. c3 Nxa2+ 22. Kb1 a5 23. f4 *
Position (FEN): 2r3k1/1Q3pp1/7p/p3p3/2q2P2/2P1B3/nP4PP/1K1R4 b - - 0 23
Black to move.
Themes: Defensive Move Endgame  
Puzzle rating: 1706
Best move: Nb4