Pokémon: The First Movie was released in Japan on July 18, 1998.
The film is the first theatrical movie in the Pokémon anime series. Its story follows Ash, Misty, and Brock as they travel to New Island, where they encounter Mewtwo, a genetically engineered Pokémon created from research connected to Mew.
The Japanese title translates as Pocket Monsters the Movie: Mewtwo Strikes Back. The English-language adaptation used the title Pokémon: The First Movie and reached North American cinemas in November 1999, more than a year after the Japanese premiere.
That difference in dates causes frequent confusion. July 18, 1998 is the original Japanese theatrical release, while November 1999 refers to the North American release. The movie also included the short film Pikachu's Summer Vacation in many theatrical presentations.