Pokémon Red and Green originally played on the Game Boy in Japan.
Nintendo’s Game Boy was a monochrome handheld system released in 1989. Its portability, link-cable support, and large installed audience made it a fitting platform for a game centered on collecting, training, battling, and trading creatures.
The original Pokémon games used the Game Boy’s Link Cable to let players trade Pokémon and battle with one another. Trading was especially important because no single version contained every Pokémon obtainable through ordinary play.
Later Pokémon releases used the Game Boy Color, Game Boy Advance, Nintendo DS, Nintendo 3DS, and Nintendo Switch. Pokémon Yellow, an enhanced first-generation release, could run on both the original Game Boy and Game Boy Color. The original hardware, however, remains the Game Boy.