Chess puzzle (Checkmate)
Moves: 1. e4 e5 2. Nf3 d6 3. Bc4 Be6 4. Bb5+ c6 5. Ba4 b5 6. Bb3 Nf6 7. Bxe6 fxe6 8.
d3 Be7 9. Nc3 O-O 10. Ne2 Nbd7 11. Ng3 d5 12. Bd2 d4 13. a3 Bd6 14. Qe2 Nc5 15.
O-O-O Na4 16. Kb1 a5 17. h4 b4 18. b3 bxa3 19. bxa4 Qb6+ 20. Ka2 *
Position (FEN): r4rk1/6pp/1qpbpn2/p3p3/P2pP2P/p2P1NN1/K1PBQPP1/3R3R b - - 2 20
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 840
Best move: Qb2#