Chess puzzle (Checkmate)
Moves: 1. e4 e5 2. d3 Bc5 3. Nf3 Nc6 4. Nc3 f5 5. exf5 d5 6. Qe2 Qe7 7. Bg5 Nf6 8.
Nxd5 Qd6 9. Nxf6+ gxf6 10. Bh4 Bxf5 11. O-O-O O-O-O 12. h3 Nd4 13. Nxd4 Bxd4
14. g4 Bg6 15. Bg2 Bxb2+ 16. Kxb2 Qb4+ 17. Kc1 Rd6 18. Qd2 Qa3+ 19. Kb1 Rb6+
20. Ka1 *
Position (FEN): 2k4r/ppp4p/1r3pb1/4p3/6PB/q2P3P/P1PQ1PB1/K2R3R b - - 8 20
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 777
Best move: Qb2#