Chess puzzle (Advantage)
Opening: Kings_Pawn_Game, Kings_Pawn_Game_McConnell_Defense
Moves: 1. e4 e5 2. Nf3 Qf6 3. c3 d6 4. d4 exd4 5. cxd4 Be7 6. Bg5 Qg6 7. Bxe7 Qxe4+ 8.
Qe2 Qxe2+ 9. Bxe2 Nxe7 10. O-O O-O 11. Nc3 c6 12. Rfe1 Na6 *
Position (FEN): r1b2rk1/pp2nppp/n1pp4/8/3P4/2N2N2/PP2BPPP/R3R1K1 w - - 2 13
White to move.
Themes:  Middlegame  
Puzzle rating: 1284
Best move: Bxa6