What were the original Japanese versions of Pokémon Red and Blue called?

The original Japanese versions of Pokémon Red and Blue were called Red and Green.

Pocket Monsters Red and Green launched in Japan on February 27, 1996. Although international audiences received Pokémon Red and Blue, Japan’s first pair used Green as the counterpart to Red. The Japanese Blue version was released later as a special edition and became the technical basis for the international games.

The change from Green to Blue was partly a localization and production decision. The overseas versions used updated artwork, dialogue, and programming derived from the Japanese Blue release, while preserving the basic adventure and version-exclusive structure of the original games.

This naming difference is a frequent source of confusion in anniversary discussions. The franchise began with Red and Green in Japan, not Red and Blue. Pokémon Green did later receive international attention through remakes and anniversary references, but the original Japanese cartridge itself was not sold worldwide in the same form.