Pokémon Red and Blue require players to defeat eight Gym Leaders.
Each Gym Leader awards a badge after being defeated, and the badges mark progress toward the Pokémon League. The Kanto journey includes gyms led by characters such as Brock, Misty, Lt. Surge, Erika, Koga, Sabrina, Blaine, and Giovanni.
The eight-gym structure became one of the most recognizable conventions of the main Pokémon games. After collecting the badges, the player can challenge the Elite Four and then face the rival at the Indigo Plateau.
The number can be confused with the Elite Four, which is a separate group of four powerful trainers. Gym Leaders are also not the same as the rival or the eventual Pokémon League Champion. Together, these stages form the game’s main trainer progression.