Pirc - classical (two knights) system
1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. Nf3 Bg7
White plays the king's pawn to e4. Black advances the queen's pawn to d6. White pushes the queen's pawn to d4.
Black develops the knight to f6. White develops the knight to c3. Black plays the g-pawn to g6.
White moves the knight to f3. Black develops the dark-squared bishop to g7.