When did Pokémon: Indigo League first air in Japan?

Pokémon: Indigo League first aired in Japan on April 1, 1997.

The season was the first television season of the Pokémon animated series. It originally aired on TV Tokyo and followed Ash Ketchum as he began his journey from Pallet Town with Pikachu, traveling through Kanto while challenging Pokémon Gyms and seeking entry to the Pokémon League.

In Japan, the series was known simply as Pocket Monsters. The English title Pokémon: Indigo League was later used for the first season in international markets. The Japanese run lasted from April 1, 1997, to January 21, 1999, and its episode count differs between Japanese and English versions.

The anime began more than a year after the first Pokémon games launched in Japan. That timing allowed the television series to build on an already established game world while giving characters such as Ash, Pikachu, Misty, and Brock a much broader international audience.