Queen's Gambit Accepted - Haberditz variation
1. d4 d5 2. c4 dxc4 3. Nf3 a6 4. e3 b5
White plays the queen's pawn to d4. Black moves the queen's pawn to d5. White moves the c-pawn to c4.
Black captures on c4 with the queen's pawn. White develops the knight to f3. Black moves the a-pawn to a6.
White advances the king's pawn to e3. Black pushes the b-pawn to b5.