Generation II added 100 new Pokémon species to the Pokémon video-game series.
The generation began with Pokémon Gold and Silver, released in Japan in 1999 for the Game Boy Color. It introduced the Johto region while also allowing players to return to Kanto after completing the main Johto adventure.
The new species ran from Chikorita, National Pokédex number 152, through Celebi, number 251. Generation II also introduced Pokémon breeding, a day-and-night system, held items, and the Dark and Steel types. These additions expanded the series beyond simply collecting a larger roster.
The figure is sometimes confused with the total number of Pokémon available after Generation II. The original Generation I roster contained 151, so adding 100 produced a combined total of 251. Generation II's 100 species therefore represent new additions, not the complete Pokédex count at that stage.