Slav Gambit, Alekhine Attack

The Alekhine Attack answers 3...dxc4 by occupying the center at once. Because Black's d-pawn has left d5, nothing contests e4, and the advance also clears the f1-bishop's diagonal toward c4. White is willing to leave the pawn on c4 for now in return for central control and quick development. Engines regard the position as roughly balanced.

Black's most frequent reply is 4...b5, which keeps the extra pawn and prepares ...b4 if White challenges the chain with a4. This approach appeared only in 1939. The older main line was 4...e5, which strikes at the center immediately. The variation became popular after Alekhine used it against Euwe in the sixth game of their 1937 World Championship rematch, where 4...e5 5. Bxc4 exd4 led to a game that Alekhine won. Later practice has shown that White scores very well against 4...e5. Black also plays 4...Nf6 and 4...e6, and White does especially well against the latter in the database.