Chess puzzle (Checkmate)
Opening: Scotch_Game, Scotch_Game_Schmidt_Variation
Moves: 1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Nxd4 Nf6 5. Bg5 Qe7 6. Nc3 h6 7. Nxc6 bxc6 8.
Bc4 hxg5 9. Qd2 Rh5 10. O-O-O d6 11. h3 Be6 12. Bxe6 fxe6 13. g4 Rh8 14. Qxg5
O-O-O 15. Qa5 Kd7 16. Qxa7 d5 17. exd5 exd5 18. Rhe1 Qd6 19. Na4 Rxh3 *
Position (FEN): 3r1b2/Q1pk2p1/2pq1n2/3p4/N5P1/7r/PPP2P2/2KRR3 w - - 0 20
White to move.
Themes: Pin Middlegame Mate in 1 
Puzzle rating: 1225
Best move: Nb6#