Queen's Indian - 4.e3
1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. e3
White advances the queen's pawn to d4. Black develops the knight to f6. White moves the c-pawn to c4.
Black pushes the king's pawn to e6. White develops the knight to f3. Black moves the b-pawn to b6.
White moves the king's pawn to e3.