Pokémon Gold Version and Silver Version are the second installments of the Pokémon series of role-playing video games, developed by Game Freak and published by Nintendo for the Game Boy Color. They were released in Japan in 1999. Pokémon Crystal, a special edition, was released roughly a year later in each region. In 2009, Nintendo remade Gold and Silver for the Nintendo DS as Pokémon HeartGold and SoulSilver. The games introduce 100 new species of Pokémon, and follow the progress of the central character, whose name the player may choose, in his quest to master Pokémon battling. Both games are independent of each other but feature largely the same plot and, while both can be played separately, it is necessary to trade between them and their backward compatible predecessors in order to fully complete the games' Pokédexes. The Johto Saga of the Pokémon anime is based on the new region introduced in the games.