When was the first Pokémon Mystery Dungeon game released in Japan?

The first Pokémon Mystery Dungeon game was released in Japan on November 17, 2005.

The first entries were Pokémon Mystery Dungeon: Red Rescue Team for Game Boy Advance and Pokémon Mystery Dungeon: Blue Rescue Team for Nintendo DS. They were developed by Chunsoft, a studio known for the Mystery Dungeon series of randomly generated, turn-based dungeon games.

Unlike the main Pokémon role-playing games, Mystery Dungeon places the player in the role of a Pokémon. A personality test traditionally determines the player's starting species, and the story often begins with the player having been transformed from a human into a Pokémon.

The Japanese launch came before the games reached other regions in 2006. Red Rescue Team and Blue Rescue Team are a matched pair rather than one game released on two versions of the same hardware: Red is the Game Boy Advance edition, while Blue is the Nintendo DS edition.