Queen's Indian - old main line - 6.O-O
1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O
White moves the queen's pawn to d4. Black develops the knight to f6. White advances the c-pawn to c4.
Black moves the king's pawn to e6. White develops the knight to f3. Black pushes the b-pawn to b6.
White advances the g-pawn to g3. Black develops the light-squared bishop to b7. White develops the light-squared bishop to g2.
Black deploys the dark-squared bishop to e7. White castles kingside.