French - Winawer - advance - 5.a3
1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3
White advances the king's pawn to e4. Black moves the king's pawn to e6. White advances the queen's pawn to d4.
Black advances the queen's pawn to d5. White develops the knight to c3. Black develops the dark-squared bishop to b4.
White pushes the king's pawn to e5. Black pushes the c-pawn to c5. White pushes the a-pawn to a3.