Gruenfeld - 5.Bg5
1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Nf3 Bg7 5. Bg5
White plays the queen's pawn to d4. Black develops the knight to f6. White advances the c-pawn to c4.
Black plays the g-pawn to g6. White develops the knight to c3. Black pushes the queen's pawn to d5.
White jumps the knight to f3. Black develops the dark-squared bishop to g7. White develops the dark-squared bishop to g5.