Chess puzzle (Checkmate)
Moves: 1. d4 Nf6 2. Bg5 d6 3. e3 g6 4. Nc3 Bg7 5. Qd2 O-O 6. e4 Ne8 7. Bh6 e5 8. dxe5
Bxh6 9. Qxh6 dxe5 10. Bd3 Nc6 11. Nf3 Nf6 12. Nd5 Nd4 13. Ng5 Qxd5 14. exd5 c5
15. dxc6 bxc6 16. Be4 Rb8 17. Rb1 Ba6 18. c3 Ne2 19. Bxc6 Rbd8 20. b3 Nxc3 21.
Rb2 *
Position (FEN): 3r1rk1/p4p1p/b1B2npQ/4p1N1/8/1Pn5/PR3PPP/4K2R b K - 1 21
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 516
Best move: Rd1#