Chess puzzle (Checkmate)
Moves: 1. e4 e5 2. Nf3 Nc6 3. c3 g6 4. d4 Bg7 5. Bg5 f6 6. Be3 d6 7. Bb5 Bd7 8. d5 Nb8
9. Bd3 Ne7 10. c4 O-O 11. O-O f5 12. exf5 Bxf5 13. Nbd2 Bxd3 14. Re1 e4 15. Nd4
Nf5 16. Nf1 Bxd4 17. Bxd4 Nxd4 18. Re3 Nc2 19. Rxd3 Nxa1 20. Re3 Qf6 21. Qxa1
Qxf2+ 22. Kh1 Qxf1+ 23. Qxf1 *
Position (FEN): rn3rk1/ppp4p/3p2p1/3P4/2P1p3/4R3/PP4PP/5Q1K b - - 0 23
Black to move.
Themes:  Endgame Back Rank Mate, Mate in 1 
Puzzle rating: 400
Best move: Rxf1#