Johto is not a generation, but rather a region in the Pokémon world. It was first explored in the second core series of Pokémon games, Pokémon Gold and Silver, and is also the setting of Pokémon Crystal, Pokémon HeartGold, and Pokémon SoulSilver. Johto is located west of Kanto, which together form a joint landmass that is south of Sinnoh and Sinjoh Ruins. The Johto region brought 100 new Pokémon to the Pokémon world, which are collectively known as Generation II Pokémon. Therefore, Johto is associated with Generation II Pokémon, but it is not a generation itself.