Chess puzzle (Checkmate)
Moves: 1. d4 d5 2. Bf4 Bf5 3. Nf3 e6 4. e3 Nf6 5. h3 Bg6 6. Bd3 c5 7. Bxg6 hxg6 8. c3
Nc6 9. Nbd2 cxd4 10. exd4 Bd6 11. Bxd6 Qxd6 12. O-O g5 13. Nxg5 Rh4 14. Ngf3
Rh6 15. Re1 O-O-O 16. Ne5 Rf8 17. Ndf3 Ne4 18. Nxc6 Qxc6 19. Ne5 Qb6 20. Qa4
Qxb2 21. Qxa7 Qxf2+ 22. Kh1 Rxh3+ 23. gxh3 *
Position (FEN): 2k2r2/Qp3pp1/4p3/3pN3/3Pn3/2P4P/P4q2/R3R2K b - - 0 23
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 840
Best move: Ng3#