Delayed Alapin Variation, with d6

After 1. e4 c5 2. Nf3 d6, White's standard move is 3. d4, which opens the position. With 3. c3, White instead prepares d4 so that a later ...cxd4 can be met by a pawn recapture, keeping a full pawn center on e4 and d4. The idea is that of the Alapin, reached here with the king's knight already developed, and play can transpose into Alapin lines. The c3-d4 chain also blunts a bishop fianchettoed on g7 by shutting it off from the long diagonal.

The difference from the 2...e6 version of the Delayed Alapin lies in the d-pawn. Standing on d6, it cannot strike at the center with ...d5 without spending another tempo. Black therefore usually puts pressure on e4 with pieces. The most common reply, 3...Nf6, chosen in more than half of games, attacks the e4-pawn at once and makes White deal with it before d4 is played. The second choice is 3...Nc6, which adds control of d4. 3...e6 and 3...a6 are less frequent; the latter is catalogued as the O'Kelly Variation, Venice System, Steiner Line. Engines also approve of 3...g6, a fianchetto that accepts the bishop may later run into the c3-d4 wall.

After 3...Nf6 4. Be2, the e4-pawn is only indirectly defended. The immediate 4...Nxe4 is met by 5. Qa4+, a check that also hits the loose knight on e4. The capture becomes an option once the c-pawns have been exchanged. In the Basman-Palatnik Gambit, 4...Nc6 5. d4 cxd4 6. cxd4 Nxe4, Black takes the pawn after the c-file has opened, and the game becomes tactical. If Black does not capture, the exchange on d4 leaves White with central pawns on e4 and d4 against Black's d6-pawn. Black then has the half-open c-file for counterplay on the queenside.

The engine rates the position as balanced. Online results are close to even, and White scores slightly better after 3...Nc6 than after 3...Nf6. The line is popular in online play. It appeals to White players who want a center and steady development without the heavy theory of the Open Sicilian main lines.