Chess puzzle (Checkmate)
Moves: 1. d4 d5 2. e3 a6 3. c4 dxc4 4. Bxc4 e6 5. Nf3 Bb4+ 6. Nc3 Bxc3+ 7. bxc3 Nf6 8.
Ba3 Ne4 9. Qc2 b5 10. Qxe4 Ra7 11. Be2 Bb7 12. Qd3 Nc6 13. O-O Na5 14. Bb4 Nc4
15. Qd1 a5 16. Bc5 Ra6 17. Bxc4 bxc4 18. Ne5 Bd5 19. Qg4 g6 20. Qf4 f5 21. Qh6
Qf6 22. Rab1 Ra8 23. Rb7 Rc8 24. Rfb1 Bxb7 25. Rxb7 a4 26. Ra7 f4 27. exf4 Qf5
28. Qg7 *
Position (FEN): 2r1k2r/R1p3Qp/4p1p1/2B1Nq2/p1pP1P2/2P5/P4PPP/6K1 b k - 2 28
Black to move.
Themes:  Middlegame Back Rank Mate, Mate in 1 
Puzzle rating: 633
Best move: Qb1#