Budapest Gambit Accepted, Main Line, Alekhine Variation

The Alekhine Variation, 4. e4, attacks the g4-knight and makes no attempt to hold the extra pawn. White lets it be recaptured and uses the time to set up a broad pawn center, aiming for space and control of d5. The cost is that the e4- and later f4-pawns can become targets if White plays inaccurately. The name refers to Alexander Alekhine, who won with it against Rabinovich at Baden-Baden 1925 and against Seitz at Hastings 1926. Engines give White a slight edge.

The usual reply is 4...Nxe5, the Abonyi Variation, when 5. f4 drives the knight away. 5...Nec6 is regarded as the most reliable retreat, and 5...Ng6 as a playable alternative. A recurring question is whether ...Bb4xc3 helps Black by doubling White's c-pawns or helps White by reinforcing the center. The Tartakower Defense, 4...d6, keeps gambiting for quick development. Theory considers the compensation insufficient, since after 5. exd6 Bxd6 6. Be2 f5 7. exf5 Qe7 White can win a piece with 8. c5 Bxc5 9. Qa4+ Nc6 10. Qxg4. On Lichess, though, Black scores well with it. 4...h5 is dubious and is best met by 5. Be2.