Chess Opening Theory/1. e4/1...c5/2. Nf3/2...d6/3. d4/3...cxd4

= Open Sicilian = Black captures White's d-pawn with cxd4 to reduce White's control of the centre, expecting the pawn to be recaptured.

White usually plays /4. Nxd4/ so that the knight may subsequently move to b3 to assist in the defence of their king following queenside castling. A knight on d4 also eyes the f5 square and once the king is safe on the queenside can support the advance of a barrage of pawns at Black's castled position.

After /4. Qxd4/ the White queen, while nicely centralised, is liable to be kicked around by Black and forced to retreat while the f3 knight is blocking the f-pawn from advancing to support a kingside attack. Provided Black avoids a transposition to the Rossolimo variation, White can have trouble activating their king's bishop after Qxd4. In general, though Qxd4 is solid enough, Nxd4 injects more life into the position, which 1. e4 players tend to be happy about.

Also in keeping with the position is the gambit /4. c3/, usually transposing into the Morra Gambit. White obtains a lead in development and aims to fully open the c-file to counter Black's influence thereof.

Theory table
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'''1. e4 c5 2. Nf3 d6 3. d4 cxd4'''