What were the Japanese versions of the first Pokémon games called?

The first Pokémon games were released in Japan as Pocket Monsters Red and Green.

They launched for the Game Boy on February 27, 1996, under the Japanese franchise name Pocket Monsters. The paired games shared their basic story and world but had different obtainable Pokémon, so players were encouraged to connect their systems and trade.

International releases used a different naming pattern. North America and Europe received Pokémon Red and Blue rather than Red and Green. The original Japanese Green version was not released internationally at that time, and the overseas Red and Blue editions were based heavily on the Japanese Blue revision.

This is why “Red and Blue” is often remembered as the original pair even though “Red and Green” came first historically. Pokémon Blue was initially a Japanese revision released after Red and Green, then became part of the international launch pair. Pokémon Yellow followed later as an enhanced version featuring Pikachu.