Chess puzzle (Advantage)
Opening: Queens_Pawn_Game, Queens_Pawn_Game_Colle_System
Moves: 1. d4 d5 2. Nf3 Nf6 3. e3 e6 4. Bd3 Nc6 5. O-O Nb4 6. Be2 Bd6 7. a3 Nc6 8. b4
O-O 9. Bb2 a5 10. Ne5 Bxe5 11. dxe5 axb4 *
Position (FEN): r1bq1rk1/1pp2ppp/2n1pn2/3pP3/1p6/P3P3/1BP1BPPP/RN1Q1RK1 w - - 0 12
White to move.
Themes:  Opening  
Puzzle rating: 1231
Best move: exf6