The Sicilian Wing Gambit for White

1.e4 c5 2.b4 cxb4 3.a3

The Wing Gambit strikes against the Sicilian before Black can settle: after 2.b4 cxb4 White deflects the c-pawn from the centre, and in the Marshall Variation 3.a3 offers a second pawn at once. If Black takes it too, White gets open lines and fast development; if he declines, White usually wins the pawn back with axb4 and builds a broad centre with c3 and d4. Stockfish sees Black slightly ahead in all the main lines, by a quarter to a third of a pawn – so the gambit is no refutation of the Sicilian but a surprise weapon for players who would rather attack than learn theory. The course is small: only 147 games reach the starting position, so the lines are short. Black's main roads are 3...d5 with the early queen sortie, 3...bxa3 (the gambit accepted), 3...e6 and 3...e5.

White trades the b-pawn for time: the c-pawn leaves the centre, and d4 comes without resistance.
Against the early queen after 3...d5 4.exd5 Qxd5 White gains tempi with Nf3 and later c3.
With axb4 White wins the pawn back, and the bishop on b4 is driven away by c3.
After the gambit accepted the knight stands actively on a3; White plays d4 and develops quickly.