Sicilian Defence ( ECO B20–B99 )

Sicilian Defence

 By advancing the c-pawn two squares, Black asserts control over the d4-square and begins the fight for the centre of the board. The move resembles 1..e5, the next most common response to 1.e4, in that respect. Unlike 1...e5, however, 1...c5 breaks the symmetry of the position, which strongly influences both players' future actions. White, having pushed a kingside pawn, tends to hold the initiative  on that side of the board. Moreover, 1...c5 does little for Black's development, unlike moves such as 1...e5, 1...g6, or 1...Nc6, which either develop a minor piece or prepare to do so. In many variations of the Sicilian, Black makes a number of further pawn moves in the opening (for example, ...d6, ...e6, ...a6, and ...b5). Consequently, White often obtains a substantial lead in development and dangerous attacking chances.

Meanwhile, Black's advance of a queenside pawn has given him a spatial advantage here and provides a basis for future operations on that flank. Often, Black's c5-pawn is traded for White's d4-pawn in the early stages of the game, granting Black a central pawn majority. The pawn trade also opens the c-file Black, who can place a rook or queen on that file to aid his queenside counter-play.