Chess puzzle (Advantage)
Opening: Scotch_Game, Scotch_Game_Scotch_Gambit
Moves: 1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4 d3 5. cxd3 Bb4+ 6. Nc3 Nf6 7. e5 Ng4 8.
O-O O-O 9. Re1 d5 10. Bb5 d4 11. a3 Ba5 12. b4 Bxb4 *
Position (FEN): r1bq1rk1/ppp2ppp/2n5/1B2P3/1b1p2n1/P1NP1N2/5PPP/R1BQR1K1 w - - 0 13
White to move.
Themes:  Middlegame  
Puzzle rating: 1363
Best move: axb4