Pokémon Gold and Silver, the first second-generation Pokémon games, were released for the Game Boy Color.
The games launched in Japan in 1999, then reached Australia and North America in 2000 and Europe in 2001. They continued the role-playing formula established by Red and Green while adding the Johto region, new Pokémon, a day-and-night cycle, breeding, held items, and new types.
Gold and Silver introduced 100 new species, increasing the series total from 151 to 251. They were compatible with the original Game Boy hardware, although their color presentation was designed for the Game Boy Color.
The platform is sometimes confused with the Game Boy Advance because later Pokémon titles, including Ruby and Sapphire, were made for that system. Gold and Silver belong to the earlier transition between the original monochrome Game Boy era and the more advanced handheld generations.