Chess puzzle (Advantage)
Opening: Vienna_Game, Vienna_Game_Stanley_Variation
Moves: 1. e4 e5 2. Bc4 Nf6 3. Nc3 Nc6 4. a3 d6 5. b4 b6 6. b5 Nd4 7. h4 Bg4 8. f3 Be6
9. a4 *
Position (FEN): r2qkb1r/p1p2ppp/1p1pbn2/1P2p3/P1BnP2P/2N2P2/2PP2P1/R1BQK1NR b KQkq - 0 9
Black to move.
Themes: Hanging Piece Middlegame  
Puzzle rating: 1136
Best move: Bxc4