Pokémon RBGY

Pokémon RBGY refers to the first generation of Pokémon games:


 * Pokémon Red and Green (Japan only)
 * Pokémon Red and Blue (localizations of Red and Green using the Japanese Blue engine)
 * Pokémon Yellow (a version with elements of the anime, such as Pikachu following you around)

The Japanese Pocket Monsters Blue was an updated version of the original Pocket Monsters Red and Green that was initially only available to subscribers of the CoroCoro Comic and featured an updated game engine and different in-game trades. Although some trades offering previously in-game trade exclusive Pokémon were removed, these Pokémon such as Mr. Mime are now available in the wild.

The localized Pokémon Red and Blue uses the newer Japanese Blue engine, however the extra features from the Japanese Blue (such as a Kadabra for Graveler trade) were altered or removed, in this case infamously spawning a "Your RAICHU went and evolved!" translation quirk.