Chess puzzle (Advantage)
Opening: Russian_Game, Russian_Game_Stafford_Gambit
Moves: 1. e4 e5 2. Nf3 Nf6 3. Nxe5 Nc6 4. Nxc6 dxc6 5. Nc3 Bc5 6. a3 *
Position (FEN): r1bqk2r/ppp2ppp/2p2n2/2b5/4P3/P1N5/1PPP1PPP/R1BQKB1R b KQkq - 0 6
Black to move.
Themes:  Opening  
Puzzle rating: 2272
Best move: Ng4