Gunderam Defense

The Gunderam Defense answers 5. Nxf3 with 5...Bf5. Black keeps the extra pawn and develops the light-squared bishop before ...e6 can shut it in. The line is named for Gerhart Gunderam, who analyzed it, together with related ...c6 and ...Bf5 setups, in a 1984 book on the gambit. The exposed bishop gives White a target. The principal theoretical reply is 6. Ne5, which prepares g4 to chase the bishop. If the bishop settles on g6, White can follow with Nxg6 to damage Black's kingside pawns. After 6...e6 7. g4, the retreat 7...Bg6 leads to calmer play, and 8. Bg2 c6 9. h4 gives White a lasting kingside initiative in exchange for the pawn. The alternative 7...Be4, the Stader Variation, produces far sharper complications. Black can also meet 6. Ne5 with 6...c6, answering 7. g4 with 7...Be6.

The direct 6. Bd3 offers a trade of bishops and is the engine's preferred move. Christoph Scheerer doubts White has enough for the pawn after 6...Bxd3 7. Qxd3 c6, when Black follows with ...e6, ...Nbd7, ...Be7 and castling. In online games 6. Bc4 is the most frequent choice, and Black wins slightly more often than White overall. The engine rates the position as a slight edge for Black.