A player must collect eight Gym Badges in Pokémon Red and Blue to enter the Pokémon League.
Each badge is awarded after defeating one of Kanto’s Gym Leaders in a Pokémon battle. The Gyms are located in major settlements across the region, including Pewter City, Cerulean City, Vermilion City, Celadon City, Fuchsia City, Saffron City, Cinnabar Island, and Viridian City.
The badges serve both as progress markers and as proof that the player has defeated Kanto’s recognized specialists. Some also allow the use of field moves outside battle, such as cutting trees, moving boulders, or traveling across water.
After earning all eight, the player can enter the Indigo Plateau and challenge the Elite Four, followed by the rival who serves as the final Pokémon League Champion battle. Badge counts can differ in later Pokémon games, but the eight-badge structure became one of the series’ most recognizable traditions.