What was the original Japanese title of Pokémon Red and Blue's first-generation counterpart?

The original Japanese title was Pocket Monsters Red and Green.

Japan received Pocket Monsters Red and Green on the Game Boy in 1996. Although the international releases became Pokémon Red and Blue, the Japanese launch used Green rather than Blue as the paired version.

A later Japanese Blue edition received updated artwork and dialogue. The code and presentation of that Blue version were used as the basis for the international Red and Blue releases, while the international games retained the broader distribution differences associated with the original pair.

This naming history causes frequent confusion because most players outside Japan know only Red and Blue. FireRed and LeafGreen were much later remakes for the Game Boy Advance, not the original first-generation titles. Gold and Silver belong to Generation II.