Ho-Oh is the first Legendary Pokémon encountered by Ash in the anime. Ash sees the rainbow-colored bird flying above him at the end of the first episode, “Pokémon, I Choose You!”, broadcast in Japan in 1997.
At that time Ho-Oh had not yet been fully explained in the television story. The Pokémon was associated with the Johto games, Pokémon Gold and Silver, which were still in development when the anime premiere aired. This early appearance helped build mystery around a creature viewers could not identify from the initial Kanto Pokédex.
Ho-Oh is a Fire/Flying-type Legendary Pokémon and is central to the Johto mythology. It is said to have revived the three Pokémon that became Raikou, Entei and Suicune after the Burned Tower fire. Ash's brief sighting is distinct from later battles and from Lugia's major role in the second Pokémon film.