Queen's Indian - 4.g3
1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3
White moves the queen's pawn to d4. Black develops the knight to f6. White moves the c-pawn to c4.
Black advances the king's pawn to e6. White develops the knight to f3. Black moves the b-pawn to b6.
White advances the g-pawn to g3.