Chess puzzle (Checkmate)
Moves: 1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Bf5 5. Ng3 Bg6 6. Nf3 Nf6 7. h4 h6 8. c3
e6 9. Qb3 Qc7 10. Ne5 Bh7 11. Bf4 Bd6 12. O-O-O O-O 13. Bc4 Nbd7 14. Rhe1 b5
15. Bxe6 Nxe5 16. Bxe5 Bxe5 17. dxe5 Nd5 18. Bxd5 cxd5 19. Qxd5 a6 20. b4 *
Position (FEN): r4rk1/2q2ppb/p6p/1p1QP3/1P5P/2P3N1/P4PP1/2KRR3 b - - 0 20
Black to move.
Themes: Queenside Attack Middlegame Mate in 1 
Puzzle rating: 434
Best move: Qxc3#