On what date did the first Pokémon animated film premiere theatrically in Japan?

The first Pokémon animated film premiered theatrically in Japan on July 18, 1998.

Known in English as Pokémon: The First Movie—Mewtwo Strikes Back, the film centers on Mewtwo, a genetically engineered Pokémon who challenges the relationship between humans and Pokémon. Ash, Pikachu, Misty, and Brock travel to New Island after receiving an invitation to a Pokémon battle.

Toho distributed the film in Japan. It was accompanied by the short film Pikachu's Vacation, which was also released on July 18, 1998. The film later reached North American theaters on November 10, 1999, although many references list November 12 because that was the originally announced release date.

The film's Japanese title is Mewtwo Strikes Back. The subtitle “The First Movie” was used prominently in English-language marketing, making it distinct from later numbered Pokémon films.