What was the Pokémon project originally called during development?

The Pokémon project was originally called Capsule Monsters during development.

Satoshi Tajiri imagined a game in which players could collect creatures and exchange them using the Game Boy link cable. The capsule idea reflected the way Pokémon could be stored and released, and it also connected with Japanese monster media that Tajiri enjoyed.

The development team commonly shortened the working name to “Capumon.” Trademark problems made “Capsule Monsters” difficult to use, so the name changed to “Pocket Monsters.” The Japanese franchise title became Pocket Monsters, later shortened internationally to Pokémon.

“Pokémon” is therefore not the project's original development name, even though it became the globally recognized brand. The final name combines the idea of pocket-sized creatures with the series' collecting and travel concept. This naming history is one reason older interviews and Japanese material sometimes refer to Pocket Monsters rather than Pokémon.