Chess puzzle (Checkmate)
Moves: 1. d4 d5 2. Nc3 e6 3. Bf4 Bd6 4. Bxd6 cxd6 5. e3 Ne7 6. Nf3 O-O 7. Be2 a6 8.
O-O f5 9. Bd3 Ng6 10. Ne2 b5 11. b3 Nc6 12. c3 b4 13. c4 dxc4 14. Bxc4 d5 15.
Bd3 a5 16. Bb5 Bb7 17. Rc1 Nge7 18. Nf4 Qb6 19. Bxc6 Bxc6 20. Nxe6 Rfc8 21. Ne5
Bb5 22. Re1 Qxe6 23. Rxc8+ Rxc8 24. Qd2 Ng6 25. Nxg6 Qxg6 26. Rc1 Bd7 27. Rxc8+
Bxc8 28. Qc2 Bd7 29. Qc5 f4 30. Qxd5+ Be6 31. Qxa5 *
Position (FEN): 6k1/6pp/4b1q1/Q7/1p1P1p2/1P2P3/P4PPP/6K1 b - - 0 31
Black to move.
Themes:  Endgame Back Rank Mate, Mate in 1 
Puzzle rating: 889
Best move: Qb1#