Chess puzzle (Checkmate)
Moves: 1. e4 c5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. d3 e6 6. Be3 Nd4 7. Qd2 Ne7 8. O-O-O
Qa5 9. Kb1 b5 10. Bh6 Bxh6 11. Qxh6 b4 12. Nce2 Nec6 13. Qd2 Rb8 14. Nxd4 Nxd4
15. Ne2 Nb5 16. Ka1 Rb6 17. Rb1 Ra6 18. Nc1 Nd4 19. c3 Qxa2+ 20. Nxa2 *
Position (FEN): 2b1k2r/p2p1p1p/r3p1p1/2p5/1p1nP3/2PP2P1/NP1Q1PBP/KR5R b k - 0 20
Black to move.
Themes:  Middlegame Mate in 1, Smothered Mate 
Puzzle rating: 918
Best move: Nb3#