Already anrwered http://pokemondb.net/pokebase/3040/what-is-pokemon-hg HG is HeartGold. there is another game similar with it. it is SS or SoulSilver. both are 4 generation game and they are remakes game from Pokemon Gold and Silver.
Heartgold-4th generation
How to change your username How to add a user avatar Why was my post hidden? Question etiquette Flags vs Downvotes Anime FAQ Official PokemonDb League
Type a Pokemon name, type, move or ability to see instant results.