Chess puzzle (Advantage)
Opening: Queens_Gambit_Declined, Queens_Gambit_Declined_Marshall_Defense
Moves: 1. d4 Nf6 2. c4 d5 3. cxd5 Nxd5 4. e4 Nf6 5. Nc3 c6 6. Nf3 Bg4 7. Be2 e6 8. O-O
Nbd7 9. Qb3 Qc7 10. Bg5 Be7 11. e5 h6 12. Bh4 g5 *
Position (FEN): r3k2r/ppqnbp2/2p1pn1p/4P1p1/3P2bB/1QN2N2/PP2BPPP/R4RK1 w kq - 0 13
White to move.
Themes:  Middlegame  
Puzzle rating: 1402
Best move: exf6