Semi-open games

Sicilian Defense

1.e4 c5

The Sicilian Defense starts with 1.e4 c5 and is catalogued under ECO B20, in the semi-open games half of the book. The catalog indexes 388 lines inside it, grouped into 327 named variations, and the position after those moves has 9 playable continuations to walk from here.

Opening repertoire map

Root edges show how often each move is played around your Elo. Use the arrow on a position to reveal the next replies.

Current position
Sicilian Defense: O'Kelly Variation
5 plies
O'Kelly Variation, Kieseritzky System
Popularity by Elo
Share of Lichess blitz, rapid, and classical games that continued with each move.
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Current setup

Move ideas

  1. 1.e4

    Claims the center with a pawn and opens lines for the queen and king’s bishop.

    Idea: Build quick development and make early castling possible.

  2. 1…c5

    Challenges d4 from the flank instead of mirroring White’s e-pawn.

    Idea: Create an unbalanced center and active queenside counterplay.

  3. 2.Nf3

    Develops the knight to f3, bringing it into the game.

    Idea: Improve piece coordination and clear the back rank for castling and the rooks.

  4. 2…a6

    Advances the a-pawn to gain queenside edge space and control new squares.

    Idea: Create useful wing space while keeping the central structure flexible.

Book continuations

Waiting for Lichess game popularity.

9 moves
c3Sicilian Defense: O'Kelly Variation, Venice System5 named lines · Sicilian Defense: O'Kelly Variation, Venice System, Barcza Line · Sicilian Defense: O'Kelly Variation, Venice System, Gambit LineAdvances the c-pawn to gain queenside space and control new squares.Idea: Create useful wing space while keeping the central structure flexible.d4Sicilian Defense: O'Kelly Variation, Normal System5 named lines · Sicilian Defense: O'Kelly Variation, Normal System, Taimanov Line · Sicilian Defense: O'Kelly Variation, Normal System, Zagorovsky LineAdvances to d4 to claim central space and control nearby key squares.Idea: Give the pieces room to develop behind a durable central foothold.c4Sicilian Defense: O'Kelly Variation, Maróczy Bind3 named lines · Sicilian Defense: O'Kelly Variation, Maróczy Bind, Paulsen Line · Sicilian Defense: O'Kelly Variation, Maróczy Bind, Robatsch LineAdvances the c-pawn to gain queenside space and control new squares.Idea: Create useful wing space while keeping the central structure flexible.b3Sicilian Defense: O'Kelly Variation, Kieseritzky System1 named lineAdvances the b-pawn to gain queenside space and control new squares.Idea: Create useful wing space while keeping the central structure flexible.b4Sicilian Defense: O'Kelly Variation, Wing Gambit1 named lineAdvances the b-pawn to gain queenside space and control new squares.Idea: Prepare a fianchetto or discourage the opponent’s expansion on that wing.Be2Sicilian Defense: O'Kelly Variation, Aronin System1 named lineDevelops the bishop to e2, bringing it into the game.Idea: Improve piece coordination and clear the back rank for castling and the rooks.d3Sicilian Defense: O'Kelly Variation, Quiet System1 named lineAdvances to d3 to claim central space and control nearby key squares.Idea: Give the pieces room to develop behind a durable central foothold.g3Sicilian Defense: O'Kelly Variation, Réti System1 named lineAdvances the g-pawn to gain kingside space and control new squares.Idea: Create useful wing space while keeping the central structure flexible.Nc3Sicilian Defense: O'Kelly Variation, Yerevan System1 named lineDevelops the knight to c3, bringing it into the game.Idea: Improve piece coordination and clear the back rank for castling and the rooks.

Named variations

Each line below is an indexed entry under Sicilian Defense. Open one to load it on the board and keep exploring from that position.

303 more named lines sit inside this family — the tree above walks all of them.

Openings from the same volume

ECO groups openings by the structures they lead to, so these families tend to share plans with the Sicilian Defense.