Chess puzzle (Advantage)
Moves: 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 Be7 5. e3 O-O 6. Nf3 b6 7. cxd5 Nxd5 8.
Bxe7 Nxe7 9. Bd3 Bb7 10. O-O Nd7 11. Ne5 Nxe5 12. dxe5 Nc6 13. Qc2 h6 14. Rad1
Qe7 15. f4 Nb4 16. Qb1 Nxd3 17. Qxd3 Rfd8 18. Qc2 Qc5 19. Qe2 a5 20. Kh1 Kh7
21. e4 *
Position (FEN): r2r4/1bp2ppk/1p2p2p/p1q1P3/4PP2/2N5/PP2Q1PP/3R1R1K b - - 0 21
Black to move.
Themes:  Middlegame  
Puzzle rating: 1720
Best move: Ba6