Chess puzzle (Advantage)
Moves: 1. e4 c6 2. f4 d5 3. e5 Qb6 4. c3 Nh6 5. h3 e6 6. d4 c5 7. Qb3 cxd4 8. Qxb6
axb6 9. cxd4 Nc6 10. Bb5 Bd7 11. Bxc6 bxc6 12. g4 c5 13. Be3 cxd4 14. Bxd4 Ra6
15. Nc3 Be7 16. Nf3 O-O 17. O-O b5 18. a3 Rfa8 19. Nd2 b4 20. Na2 Ra4 21. b3 *
Position (FEN): r5k1/3bbppp/4p2n/3pP3/rp1B1PP1/PP5P/N2N4/R4RK1 b - - 0 21
Black to move.
Themes:  Middlegame  
Puzzle rating: 1209
Best move: Rxa3