Classical Variation, Greco Gambit, Modern Line

Instead of the traditional 6. cxd4, White plays 6. e5 and gains time against the f6-knight. The d4-pawn stays in Black's hands for the moment. White normally wins it back with cxd4 once the knight has moved. The resulting center has pawns on e5 and d4 rather than the e4/d4 pair of the old main line. The advance also removes e4 as a target, the pawn Black wins in the 6. cxd4 Bb4+ 7. Nc3 Nxe4 lines. Sveshnikov popularized the idea, and it has become more common in the 21st century.

The principled reply is 6...d5, which attacks the c4-bishop and secures e4 as a post for the knight. It is the most frequent choice and the only common answer after which Black outscores White in online games. The usual sequel is 7. Bb5 Ne4 8. cxd4 Bb6, while Anderssen often chose 8...Bb4+. Jobava has preferred 7. Be2. The immediate knight moves 6...Ng4 and 6...Ne4 are the next most popular replies, and White scores well against both. The engine considers the position level.