The original Pokémon Red and Green games first appeared in Japan on the Game Boy.
Game Freak designed the role-playing games for Nintendo’s monochrome handheld, using its portability and link-cable connection as central parts of the experience. Players could connect two Game Boys to battle or trade Pokémon between compatible cartridges.
That trading feature was especially important because the two versions contained different Pokémon. Players therefore needed another game and another system to complete their collections, creating a social reason to connect with friends.
The games later received international versions titled Pokémon Red and Blue. Pokémon Yellow followed in Japan as a revised Game Boy release, but it was not the franchise’s original game pair.