Heiankyo Alien (平安京エイリアン, Heian-kyō Eirian), known as Digger in North America, is a maze video game created by the University of Tokyo's Theoretical Science Group (TSG) in 1979. The game was originally developed and released as a personal computer game in 1979, and was then published by Denki Onkyō Corporation (電気音響株式会社, Denki Onkyō Kabushiki Gaisha) as an arcade game in November 1979. In 1980, the arcade game was released in North America as Digger by Sega-Gremlin, with minor changes in appearance.