Old Sicilian

The Old Sicilian is the position after 2...Nc6, in which Black develops the queen's knight to its natural square before committing to a pawn structure. The knight watches d4 and e5, and Black keeps both ...d5 and ...e5 available as single-step advances; if ...d5 can later be achieved in one move, the tempo that 2...d6 would have cost is saved. In practice the move matters mainly as a route into particular Open Sicilian systems.

White's most frequent answer is 3. d4, and after 3...cxd4 4. Nxd4 Black chooses among several distinct systems. 4...g6 is the Accelerated Dragon, where the knight on c6 rules out a centralizing Qxd4 by White. 4...Nf6 5. Nc3 e5 is the Sveshnikov: the hit on the knight combined with the threat of ...Bb4 pushes White into 6. Ndb5, and the game turns on Black's weakened d5-square. 4...Nf6 5. Nc3 d6 is the Classical Sicilian, while 4...e6 reaches the Taimanov, which can also arise from 2...e6.

The drawback of this move order is 3. Bb5, the Nyezhmetdinov-Rossolimo Attack, the main alternative to opening the center. White is often ready to exchange on c6 and saddle Black with doubled c-pawns. Because this option exists, 2...Nc6 is considered committal, and players aiming for systems reachable by other orders, such as the Taimanov, often prefer a different second move. Both the Open lines and the Rossolimo produce sharp, asymmetrical and heavily analyzed positions, yet White's pressure is usually built on a lasting structural weakness, d5 in the Sveshnikov or the c-pawns in the Rossolimo, rather than a quick mating attack.

3. Bc4, a delayed Bowdler Attack, is the second most popular move and a club-level favorite, but it is not critical: ...e6 takes the sting out of the bishop's pressure on f7, and Black scores slightly better than White against it. 3. Nc3 is a waiting move that postpones d4, though 3...e5 can prevent the advance altogether. 3. c3 is a delayed Alapin aiming for a broad center, 3. d3 and 3. g3 head for closed setups with a kingside fianchetto, and the rare 3. b4 is the Portsmouth Gambit. Since ...Nc6 is a normal move for Black in the Alapin and Closed systems, these orders seldom have independent significance.

The position is among the most frequently reached named openings, results are almost evenly split, and the engine gives White no more than a small edge.