What are the key differences between the Pirc Defense and the King's Indian Defense, and how do these differences impact the strategic and tactical aspects of the game?

The key differences between the Pirc Defense and the King's Indian Defense lie in their pawn structures and piece placements. The Pirc Defense focuses on solidly defending the center with pawns, while the King's Indian Defense aims for a more dynamic pawn structure and aggressive piece play. These differences impact the game strategically by influencing the type of positions that arise and tactically by determining the types of attacks and counterattacks that each side can launch.