Chess puzzle (Advantage)
Moves: 1. b3 d5 2. Bb2 Nc6 3. e3 e5 4. c4 d4 5. exd4 exd4 6. d3 Nf6 7. Be2 Bc5 8. Nd2
O-O 9. Ngf3 Bg4 10. O-O Re8 11. Re1 Bxf3 12. Bxf3 Rxe1+ 13. Qxe1 Nb4 14. Qf1
Qe7 15. Ne4 Nxe4 16. Bxe4 c6 17. a4 Re8 18. g3 a5 19. Ba3 Nc2 20. Ra2 *
Position (FEN): 4r1k1/1p2qppp/2p5/p1b5/P1PpB3/BP1P2P1/R1n2P1P/5QK1 b - - 3 20
Black to move.
Themes:  Middlegame  
Puzzle rating: 1473
Best move: Nxa3