Chess puzzle (Advantage)
Opening: Pirc_Defense, Pirc_Defense_Other_variations
Moves: 1. e4 d6 2. d4 Nf6 3. Bd3 e5 4. c3 Bg4 5. f3 Bd7 6. Bg5 Be7 7. Nd2 h6 8. Be3
Nh5 9. Ne2 Bh4+ 10. g3 Bg5 11. Bxg5 Qxg5 12. Qc2 Nc6 13. O-O-O O-O-O 14. Kb1
Kb8 15. Qb3 Qe3 16. Qc2 exd4 17. cxd4 *
Position (FEN): 1k1r3r/pppb1pp1/2np3p/7n/3PP3/3BqPP1/PPQNN2P/1K1R3R b - - 0 17
Black to move.
Themes:  Middlegame  
Puzzle rating: 1710
Best move: Nb4