Chess puzzle (Checkmate)
Moves: 1. d4 Nc6 2. Nc3 e6 3. e4 d5 4. f3 Nge7 5. Bd3 g6 6. Be3 Bg7 7. Bb5 Qd6 8. exd5
Nxd5 9. Nxd5 exd5 10. c3 O-O 11. Bd3 Re8 12. Qd2 Na5 13. O-O-O Nc4 14. Bxc4
dxc4 15. Bh6 Qa6 16. Kb1 Bf5+ 17. Ka1 Bd3 18. Bxg7 Kxg7 19. h4 Re6 20. h5 Qxa2+
21. Kxa2 *
Position (FEN): r7/ppp2pkp/4r1p1/7P/2pP4/2Pb1P2/KP1Q2P1/3R2NR b - - 0 21
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 856
Best move: Ra6#