Chess puzzle (Checkmate)
Opening: Nimzowitsch_Defense, Nimzowitsch_Defense_Scandinavian_Variation
Moves: 1. e4 d5 2. e5 Nc6 3. d4 f6 4. f4 fxe5 5. fxe5 Bf5 6. c3 Qd7 7. Bd3 e6 8. Bxf5
exf5 9. Ne2 g6 10. Nf4 Bh6 11. O-O Nge7 12. Nd2 Bxf4 13. Rxf4 g5 14. Rf1 O-O-O
15. Nb3 f4 16. Nc5 Qe8 17. Qa4 h5 18. Qb5 b6 19. Qa6+ Kb8 *
Position (FEN): 1k1rq2r/p1p1n3/Qpn5/2NpP1pp/3P1p2/2P5/PP4PP/R1B2RK1 w - - 2 20
White to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 717
Best move: Qb7#