Pocket Monsters Stadium(ポケモンスタジアム?) is the first game of the Pokémon Stadium series, and was released in Japan in 1998. This version featured only forty-two Pokémon instead of all 151 Generation I Pokémon, and was not released outside of Japan. This game was originally intended for the Nintendo 64DD format, but as the Nintendo 64DD was a commercial failure, Pokémon Stadium transferred to cartridge format. There were also plans for an expansion disk, a proposed add-on for the Nintendo 64DD, but the expansion disk was never released.