Chess puzzle (Equality)
Moves: 1. d4 d5 2. Nc3 e6 3. Nf3 c6 4. e4 Be7 5. Bd3 Bb4 6. Bd2 a5 7. a3 Bxc3 8. Bxc3
Nh6 9. exd5 cxd5 10. Ne5 O-O 11. Qf3 Nc6 12. Qg3 Qf6 13. Bb5 Nxe5 14. dxe5 Qf5
15. Bd3 Qh5 16. Bd2 Nf5 17. Bxf5 Qxf5 18. O-O-O b5 19. h4 Qe4 20. h5 b4 21.
axb4 *
Position (FEN): r1b2rk1/5ppp/4p3/p2pP2P/1P2q3/6Q1/1PPB1PP1/2KR3R b - - 0 21
Black to move.
Themes:  Middlegame  
Puzzle rating: 1508
Best move: axb4