Chess puzzle (Advantage)
Opening: Queens_Gambit_Accepted, Queens_Gambit_Accepted_Old_Variation
Moves: 1. d4 d5 2. c4 dxc4 3. e3 Nf6 4. Bxc4 e6 5. Ne2 Bb4+ 6. Nbc3 O-O 7. O-O Nc6 8.
a3 e5 *
Position (FEN): r1bq1rk1/ppp2ppp/2n2n2/4p3/1bBP4/P1N1P3/1P2NPPP/R1BQ1RK1 w - - 0 9
White to move.
Themes:  Opening  
Puzzle rating: 1542
Best move: axb4