Players must defeat eight Gym Leaders in Pokémon Red and Blue before entering the Pokémon League.
Each victory awards a Gym Badge and advances the player toward the League challenge at Indigo Plateau. The Gym Leaders specialize in different battle styles, including Brock’s Rock-type team, Misty’s Water-type team, and Sabrina’s Psychic-type team.
The eight badges are more than trophies. They also represent the player’s progress and grant access to abilities or obedience levels connected with the game’s progression system. Once all eight are collected, the player can challenge the Elite Four and the rival who serves as the final Champion battle.
The eight-Gym structure became one of the most recognizable conventions in the main Pokémon games. Later regions changed the characters and layouts, but many retained a comparable badge-based journey.