Chess puzzle (Checkmate)
Opening: Queens_Pawn_Game, Queens_Pawn_Game_Other_variations
Moves: 1. d4 d5 2. e3 Nc6 3. Bb5 a6 4. Bxc6+ bxc6 5. Nf3 Bg4 6. h3 Bh5 7. g4 Bg6 8.
Ne5 Qd6 9. Nc3 f6 10. Nxg6 hxg6 11. Bd2 e5 12. Qe2 Ne7 13. O-O-O Rb8 14. a3 Nc8
15. Na4 Nb6 16. Nc5 Nd7 17. Nxa6 Qxa3 18. bxa3 *
Position (FEN): 1r2kb1r/2pn2p1/N1p2pp1/3pp3/3P2P1/P3P2P/2PBQP2/2KR3R b k - 0 18
Black to move.
Themes: Queenside Attack Middlegame Mate in 1 
Puzzle rating: 899
Best move: Bxa3#