English Rat, Lisbon Gambit

The Lisbon Gambit is a branch of the English Rat. After 3. dxe5, Black plays 3...Nc6 and does not recapture. The knight develops with tempo against the advanced e5 pawn and keeps the queens on the board, so Black avoids the queenless endgame that follows 3...dxe5. White is a pawn up but has doubled e-pawns, and the d- and e-files are half-open. Black aims to turn the lead in development into active piece play while White's king is still in the center.

By far the most common reply is 4. exd6, which takes a second pawn. It gives up the extra central pawn on e5 but opens lines for Black, and White has to play accurately afterwards. In practice Black scores well in that line. The quieter 4. Nf3 defends e5 and keeps the material plus without opening the position, and White's results are better there. 4. Nc3 is a less frequent alternative. The engine gives White a slight edge and lists 4. exd6, 4. Nf3 and 4. e6 as its top choices. Black still has the better overall score in online games, which reflects how difficult the resulting positions are to handle accurately.