Chess puzzle (Advantage)
Moves: 1. d4 Nf6 2. Nf3 e6 3. Bf4 d5 4. e3 c5 5. c3 Nbd7 6. Qb3 b6 7. Bb5 c4 8. Qc2 a6
9. Bc6 Ra7 10. Bb8 Rc7 11. Bxc7 Qxc7 12. Bxd7+ Bxd7 13. Nbd2 Bd6 14. e4 dxe4
15. Nxe4 Nxe4 16. Qxe4 O-O 17. Ng5 g6 18. Qh4 h5 19. g4 Qc6 20. O-O-O *
Position (FEN): 5rk1/3b1p2/ppqbp1p1/6Np/2pP2PQ/2P5/PP3P1P/2KR3R b - - 2 20
Black to move.
Themes:  Middlegame  
Puzzle rating: 2125
Best move: f6