Chess puzzle (Checkmate)
Moves: 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. f4 Be7 8. Qf3
h6 9. Bxf6 Bxf6 10. O-O-O Qc7 11. Kb1 Nd7 12. g4 b5 13. Ndxb5 axb5 14. Nxb5 Qa5
15. Nxd6+ Ke7 16. a3 Rb8 17. e5 Nxe5 18. fxe5 Qxe5 19. Nc4 Rxb2+ 20. Kc1 Rb1+
21. Kxb1 *
Position (FEN): 2b4r/4kpp1/4pb1p/4q3/2N3P1/P4Q2/2P4P/1K1R1B1R b - - 0 21
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 1091
Best move: Qa1#