The original Pokémon games in Japan were released for the Game Boy.
Pocket Monsters Red and Green used Nintendo's handheld hardware to create a role-playing adventure built around exploration, collection, and battles. The Game Boy's link cable was especially important because it allowed players to trade Pokémon and battle one another.
That trading feature addressed a major design goal: no single version contained every Pokémon. Players needed to connect different versions to complete their collection, giving the portable system a social role beyond ordinary single-player play.
The enhanced Pokémon Blue was also released for Game Boy in Japan. Later, Pokémon Yellow was designed for the Game Boy Color palette, but the franchise began on the original monochrome Game Boy.