Classical Variation, Sozin Attack

With 6. Bc4 White points the bishop at Black's kingside and the e6-square instead of pinning the f6-knight as in the Richter-Rauzer. The line takes its name from the Russian master Veniamin Sozin, who developed it in the 1930s, and is also called the Fischer-Sozin Attack after Bobby Fischer. It is generally seen as less common and less ambitious than 6. Bg5. The engine regards the position as roughly balanced.

The usual reply, 6...e6 (the Leonhardt Variation), blunts the bishop, and White then aims to strike at e6 with f4 and f5. After 6...e6 7. Be3 Be7 White can castle kingside or choose 8. Qe2 and 9. O-O-O, the Velimirovic Attack. These lines are very sharp and heavily analyzed. The second most popular reply, 6...g6, heads for a Dragon setup but runs into the Magnus Smith trap and is considered dubious. White scores slightly better against it than against 6...e6. Benko's 6...Qb6, the Anti-Sozin, makes White decide at once what to do with the d4-knight, and it usually produces more positional play.