Carlson Gambit

The Carlson Gambit arises when White meets the French with 2. d4 d5 3. Nf3, leaving the e4-pawn undefended, and answers 3...dxe4 with 4. Ne5. The knight move is the gambit's main point, because the obvious attempt to win the pawn back fails. After 3...dxe4 4. Ng5 Nf6 5. Nc3 Bb4 6. Bd2 Qxd4, Black has more than enough defenders and keeps the extra material. Instead, White relies on a centralized knight that is awkward to dislodge, together with a lead in development. The line is also discussed under the name Perseus Gambit, which can arise from 2. Nf3 d5 3. d4.

The natural reply 4...Nf6 is the most common. It protects the e4-pawn and covers h5, and Black scores well after it. Trying to chase the knight with 4...f6 runs into 5. Qh5+ g6 6. Nxg6 hxg6 7. Qxh8, which wins the exchange and more for White. Even so, the move is played fairly often, and White's results after it are better than average. Black can also try 4...Nd7 to exchange the e5-knight, or develop with 4...Bd6. The engine gives Black a clear advantage, and Black wins more often than White in practice.