Chess puzzle (Advantage)
Moves: 1. e4 c5 2. d4 cxd4 3. c3 Nc6 4. Nf3 g6 5. cxd4 Bg7 6. Bc4 d6 7. O-O Nf6 8. Nc3
e6 9. Bg5 d5 10. exd5 exd5 11. Nxd5 O-O 12. Re1 Be6 13. Ne3 Bxc4 14. Nxc4 Qd5
15. b3 Ne4 16. Ne3 Qd6 17. Nc4 Qd7 18. Rxe4 h6 19. Be3 f5 20. Rf4 g5 21. Nh4 *
Position (FEN): r4rk1/pp1q2b1/2n4p/5pp1/2NP1R1N/1P2B3/P4PPP/R2Q2K1 b - - 1 21
Black to move.
Themes:  Middlegame  
Puzzle rating: 1333
Best move: gxf4