Sicilian Invitation

The Sicilian Invitation is the reply 1...c5 to the Hungarian Opening. Instead of putting a pawn on d5 or e5, Black takes a share of the center from the flank. The c-pawn controls d4 and opens the d8–a5 diagonal for the queen, and it keeps the remaining central pawns uncommitted. The name comes from the idea that White can accept a Sicilian Defense by playing e4 on the next move, so the opening works as an offer to change the type of game.

By far the most frequent reply is 2. Bg2, which completes the fianchetto and makes no commitment in the center. The bishop now presses down the long diagonal toward b7 and the queenside, the area Black has just begun to expand on. White can keep options open with Nf3, short castling and a later choice of c4, d3 with e4, or d4. Black usually decides the structure: by building a broad pawn center or by fianchettoing as well. Many games transpose into reversed or symmetrical flank openings.

The main alternative is 2. e4, which takes up the invitation. The resulting position is the Sicilian Defense: Lasker-Dunne Attack, a closed-style Sicilian line in which White fianchettoes the king's bishop instead of opening the center with d4. The engine's first choice is 2. c4, which leads to a symmetrical English-type structure with both c-pawns advanced. 2. Nf3 is seldom played; it develops while leaving every pawn structure open. Also uncommon is 2. b3, a double-fianchetto plan that aims a second bishop at d4 and the long dark diagonal.

The engine assesses the position as roughly balanced, and the main moves 2. Bg2, 2. c4 and 2. Nf3 all keep it level. In online play results are close to even, with a small plus for White and very few draws. Among named openings the line ranks in the upper tier by the number of games reaching it. Little theory is specific to the position itself, because what a player needs to know depends almost entirely on which Sicilian, English or fianchetto structure the game turns into.