Chess puzzle (Checkmate)
Moves: 1. d4 Nf6 2. Nc3 d5 3. Bf4 c5 4. e3 Qb6 5. Na4 Qa5+ 6. c3 cxd4 7. exd4 Nc6 8.
b4 Qd8 9. Nb2 Bg4 10. Qb3 e6 11. Bd3 Bd6 12. Bg3 O-O 13. Ne2 Rc8 14. O-O Bxe2
15. Bxe2 Ne4 16. Bd3 Nd2 17. Bxh7+ Kh8 18. Qc2 Nxf1 19. Rxf1 Bxg3 20. fxg3 g6
21. Bxg6 fxg6 22. Qxg6 Rxf1+ 23. Kxf1 Qf8+ 24. Ke2 Qf5 25. Qh6+ Kg8 26. Nd3 Rf8
27. Nf4 Qc2+ 28. Kf3 Qxc3+ 29. Kg4 Qxd4 30. Qxe6+ Rf7 31. Qe8+ Kg7 32. Kh3 Rxf4
33. gxf4 Qxf4 34. Qd7+ Qf7 35. Qg4+ Kf8 36. b5 Ne5 37. Qc8+ Kg7 38. Qc3 Qe6+
39. Kg3 Qg4+ 40. Kf2 Qf4+ 41. Kg1 d4 42. Qc7+ Kf6 43. Qd8+ Kf5 44. Qf8+ Ke4 45.
Qg7 Qc1+ 46. Kf2 Qe3+ 47. Kf1 d3 48. Qxb7+ Kd4 49. Qxa7+ Ke4 50. Qxe3+ Kxe3 51.
Ke1 d2+ 52. Kd1 Kd3 53. b6 Nc4 54. b7 *
Position (FEN): 8/1P6/8/8/2n5/3k4/P2p2PP/3K4 b - - 0 54
Black to move.
Themes:  Endgame, Knight Endgame Mate in 1 
Puzzle rating: 473
Best move: Nb2#