Chess puzzle (Advantage)
Moves: 1. e4 c5 2. Nf3 Nc6 3. g3 g6 4. Bg2 Qc7 5. O-O e6 6. Re1 Bg7 7. c3 Nge7 8. d3
b6 9. a4 Bb7 10. Na3 a6 11. Bf4 e5 12. Be3 h6 13. Nc4 d6 14. d4 O-O 15. dxe5
dxe5 16. Qc2 Rad8 17. Rad1 f5 18. exf5 Nxf5 19. Bc1 e4 20. Rxe4 *
Position (FEN): 3r1rk1/1bq3b1/ppn3pp/2p2n2/P1N1R3/2P2NP1/1PQ2PBP/2BR2K1 b - - 0 20
Black to move.
Themes:  Middlegame  
Puzzle rating: 2099
Best move: Nb4