Pokémon Gold and Silver are two role-playing video games made by Game Freak and published by Nintendo for the Game Boy Color handheld. They are the second games in the Pokémon series, and increased the number of Pokémon to 251. The Pokémon Ho-oh and Lugia, respectively, are featured in the boxart. A special version named "Pokémon Crystal", which had the Pokémon Suicune on the cover, was released around a year later. Pokemon Gold and Silver are backward-compatible with the original Game Boy (except in Korea), but Pokemon Crystal requires a Game Boy Color or Game Boy Advance.