What was the name of the Japan-only Nintendo 64 game that preceded the Western release of Pokémon Stadium?

Pocket Monsters Stadium was the Japan-only Nintendo 64 game that preceded the Western release of Pokémon Stadium.

Pocket Monsters Stadium was developed and published by Nintendo and released in Japan in 1998. It was a strategy role-playing game built around three-dimensional Pokémon battles. The game is also known as Pocket Monster Stadium or Pokémon Stadium in English-language references.

Its original scope changed substantially during development. The project was initially planned for Nintendo’s cancelled 64DD hardware and was intended to include every Pokémon from the Game Boy games. Technical and production constraints reduced the playable roster to 40 Pokémon in the Japanese release.

The later game marketed internationally as Pokémon Stadium was released in Japan in 1999 and supported all 151 Pokémon from Red, Blue, and Yellow. That version reached North America and Europe in 2000. The similar names and different regional numbering explain why the Japan-only predecessor is frequently confused with the Western Pokémon Stadium release.