Pokémon Gold and Silver introduced 100 new Pokémon species.
Released in Japan in 1999 for the Game Boy Color, the games began Pokémon’s second generation. Their new species were numbered 152 through 251 in National Pokédex order, following the original 151 from Pokémon Red and Green.
Gold and Silver also expanded the series with the Johto region, a real-time clock, Pokémon breeding, held items, and two new types: Dark and Steel. Shiny Pokémon, which have alternate colorations, were another notable addition. These features made the games more than a simple visual upgrade.
The sequel structure also allowed players to revisit Kanto after completing the Johto story. That post-game journey is one reason Gold and Silver are often remembered as unusually large Pokémon adventures. The games’ release dates are sometimes confused with their international launches, which occurred in 2000 and 2001.