Which generation began with Pokémon Gold and Silver?

Pokémon Gold and Silver began Generation II of the Pokémon video game series.

The games were first released in Japan in 1999 for the Game Boy Color. They followed the original Red, Green, Blue, and Yellow games and added 100 new Pokémon species, bringing the series into its second generation.

Gold and Silver introduced several lasting features, including the Johto region, a day-and-night cycle, breeding, Pokémon eggs, held items, and the Dark and Steel types. They also added Shiny Pokémon and allowed players to revisit Kanto after completing the main Johto adventure.

Generation labels describe major waves of Pokémon species and core games, not simply console generations. Gold and Silver are therefore Generation II even though they run on the Game Boy Color and remain compatible with some Game Boy-era design ideas. Pokémon Crystal later served as an enhanced version of the same generation.