The original Pokémon Red and Green games were released for the Game Boy.
Nintendo launched the Game Boy in 1989, several years before Pokémon. By 1996, the handheld was technically old, but its large installed audience and affordable hardware made it an effective platform for Game Freak's creature-collecting role-playing game.
The games used the Game Boy's link-cable feature as a central part of their design. Players could trade Pokémon between cartridges and battle friends, and some species could only be obtained by exchanging them. The paired versions were therefore more than cosmetic variations.
Pokémon Yellow later appeared for the Game Boy as an enhanced version. International Red and Blue releases also ran on the original Game Boy, although they could be played on later compatible hardware. The first games are sometimes associated with the Game Boy Color because the series became closely linked with that system, but the initial Japanese launch preceded the Game Boy Color.