Chess puzzle (Advantage)
Opening: Nimzowitsch_Defense, Nimzowitsch_Defense_Kennedy_Variation
Moves: 1. e4 e5 2. d4 Nc6 3. d5 Nce7 4. Nf3 d6 5. Bg5 Bg4 6. h3 Bh5 7. Nc3 f6 8. Be3
Nh6 9. g4 Bg6 10. g5 Nf7 11. gxf6 gxf6 12. h4 h5 13. Rg1 Rg8 14. Qd2 a6 15.
O-O-O Qd7 16. Be2 O-O-O 17. Bd3 f5 18. Qe2 fxe4 19. Bxa6 *
Position (FEN): 2kr1br1/1ppqnn2/B2p2b1/3Pp2p/4p2P/2N1BN2/PPP1QP2/2KR2R1 b - - 0 19
Black to move.
Themes:  Middlegame  
Puzzle rating: 1500
Best move: exf3