Chess puzzle (Checkmate)
Moves: 1. d4 g6 2. c4 Bg7 3. Nc3 Nf6 4. e4 d6 5. Nf3 O-O 6. Bd3 e5 7. d5 a5 8. a4 Na6
9. Be3 Nb4 10. O-O Nxd3 11. Qxd3 Ng4 12. h3 Nxe3 13. Qxe3 f5 14. Nd2 f4 15. Qe2
g5 16. f3 h5 17. Qf2 g4 18. hxg4 hxg4 19. Rfd1 g3 20. Qe2 Qh4 21. Kf1 *
Position (FEN): r1b2rk1/1pp3b1/3p4/p2Pp3/P1P1Pp1q/2N2Pp1/1P1NQ1P1/R2R1K2 b - - 3 21
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 431
Best move: Qh1#