Centre game - Kieseritsky variation
1. e4 e5 2. d4 exd4 3. Nf3 c5 4. Bc4 b5
White moves the king's pawn to e4. Black pushes the king's pawn to e5. White pushes the queen's pawn to d4.
Black captures on d4 with the king's pawn. White develops the knight to f3. Black advances the c-pawn to c5.
White develops the light-squared bishop to c4. Black pushes the b-pawn to b5.