Chess puzzle (Crushing)
Opening: Queens_Pawn_Game, Queens_Pawn_Game_Chigorin_Variation
Moves: 1. d4 d5 2. Nc3 e6 3. f3 Bb4 4. Bd2 Ne7 5. e4 O-O 6. e5 Nf5 7. Bc1 Qh4+ 8. g3
Nxg3 9. hxg3 Qxh1 10. Nh3 Qh2 11. Bf4 Nc6 12. Qd3 b6 13. O-O-O Qh1 14. Qe2 Nxd4
15. Rxd4 Bxc3 16. bxc3 a5 17. Rd1 Ba6 18. Qxa6 *
Position (FEN): r4rk1/2p2ppp/Qp2p3/p2pP3/5B2/2P2PPN/P1P5/2KR1B1q b - - 0 18
Black to move.
Themes:  Middlegame  
Puzzle rating: 837
Best move: Rxa6