Chess puzzle (Checkmate)
Moves: 1. e4 e6 2. Nf3 d5 3. e5 c5 4. b4 c4 5. c3 b5 6. d4 a5 7. Ba3 Nc6 8. bxa5 Bxa3
9. Nxa3 Qxa5 10. Nb1 b4 11. cxb4 Nxb4 12. Nc3 Nd3+ 13. Bxd3 Qxc3+ 14. Ke2 cxd3+
15. Ke3 d2+ 16. Kf4 g5+ 17. Kg3 Nh6 18. Qxd2 Nf5+ 19. Kh3 h5 20. Qxc3 *
Position (FEN): r1b1k2r/5p2/4p3/3pPnpp/3P4/2Q2N1K/P4PPP/R6R b kq - 0 20
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 813
Best move: g4#