Chess puzzle (Checkmate)
Moves: 1. d4 c5 2. d5 d6 3. e4 Nf6 4. Nc3 Bg4 5. Nf3 e6 6. Bg5 h6 7. Bh4 g5 8. Bg3 Bg7
9. Bb5+ Nbd7 10. Bxd6 a6 11. Bxd7+ Qxd7 12. Bxc5 O-O-O 13. O-O exd5 14. e5 Nh5
15. h3 Bf5 16. Nd4 Nf4 17. Bd6 Bxh3 18. Qf3 Bxg2 19. Nxd5 Bxf3 *
Position (FEN): 2kr3r/1p1q1pb1/p2B3p/3NP1p1/3N1n2/5b2/PPP2P2/R4RK1 w - - 0 20
White to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 1021
Best move: Nb6#