Modern Variations, Main Line

The Main Line of the Modern Variations is the standard Open Sicilian position after 4...Nf6. The knight develops with an immediate threat to e4, and because 2...d6 already covers e5, White cannot evict it with e4-e5. White must therefore deal with the e4-pawn at once, which rules out 5. c4 for a Maroczy Bind: 5...Nxe4 simply wins a pawn. Results are almost perfectly even, and the engine regards the position as roughly balanced.

The overwhelming choice is 5. Nc3. It defends e4 while developing, prepares queenside castling, watches d5 in case Black later plays ...e5, and helps guard the c-file when White's king goes long. From here Black commits to a system: 5...a6 is the Najdorf, 5...Nc6 the Classical, and 5...g6 the Dragon. Each has its own extensive body of theory. In the Najdorf, for example, 6. Bg5 e6 7. f4 was long regarded as the principal line.

The alternatives are much rarer. 5. Bd3 protects the pawn but places the bishop where it blocks the queen's defense of d4, so after ...Nc6 White has to exchange on c6 or lose a tempo protecting the knight. Black scores slightly better against it. 5. f3, the Prins Variation, covers e4 with a pawn and keeps c2-c4 available for a bind. Black normally answers 5...e5 6. Nb3 and then either attacks the c4-point, as in 6...Be6 7. c4 Nbd7 8. Be3 Rc8 9. Nc3 Bxc4, or strikes in the center with 6...d5 7. Bg5 d4. White can instead play the zwischenzug 6. Bb5+, the Venice Attack, aiming for Nf5. This gives up on c4, because Black gains time with ...a6 and ...b5. White's results in the Prins are better than in the other lines.

5. Bc4, the Ginsberg Gambit, leaves e4 to its fate in exchange for pressure on f7, with Qh5 as the main idea. If Black accepts with 5...Nxe4, then 6. Bxf7+ Kxf7 7. Qh5+ Kg8 8. Qd5+ regains the knight and leaves Black's king stuck in the center. The alternative 7...Kf6 exposes the king even further.