Sicilian - wing gambit - Carlsbad variation
1. e4 c5 2. b4 cxb4 3. a3 bxa3
White advances the king's pawn to e4. Black moves the c-pawn to c5. White moves the b-pawn to b4.
Black captures on b4 with the c-pawn. White plays the a-pawn to a3. Black captures on a3 with the b-pawn.