Herrstrom Gambit

The Herrstrom Gambit answers the Zukertort Opening by placing a pawn where White's knight can take it at once. The move contributes nothing to development or the center. Black's only justification is tempo: after 2. Nxg5 e5 the central pawn attacks the knight, which must retreat. Black then hopes to keep harassing it while building a pawn center. The cost is a pawn and a permanently loosened kingside, and the engine assesses the position as a large advantage for White. Its preferred replies are 2. Nxg5, 2. h3 and 2. g3.

Accepting with 2. Nxg5 is the most common answer in online play, and White scores well after it. Many players decline instead. With 2. g3 they aim for a normal fianchetto setup, and with 2. d4 they occupy the center, so the g5-pawn becomes a mere weakening rather than a sacrifice. In Lichess games Black has done better than White after 2. g3, and results after 2. d4 are close to even. Across all games reaching 1...g5, the score is almost exactly balanced, a reflection of the surprise value it carries in fast online chess rather than of its objective merit.