Chess puzzle (Advantage)
Opening: Queens_Pawn_Game, Queens_Pawn_Game_Zukertort_Variation
Moves: 1. d4 d5 2. Nf3 e6 3. Bf4 c5 4. e3 Qb6 5. Nc3 Bd7 6. Rb1 a6 7. Be2 Nc6 8. O-O
Nf6 9. Na4 Qa5 10. c3 Nxd4 11. cxd4 Bxa4 12. b3 Bb5 13. Bxb5+ Qxb5 14. Rc1 b6
15. Ne5 Be7 *
Position (FEN): r3k2r/4bppp/pp2pn2/1qppN3/3P1B2/1P2P3/P4PPP/2RQ1RK1 w kq - 2 16
White to move.
Themes:  Middlegame  
Puzzle rating: 1669
Best move: a4