The show began as six ten-minute episodes on BBC Two Scotland, broadcast at around midnight on Fridays starting in December 2005. The episodes were also able to be viewed online from the BBC's web site. A second series, consisting of six half-hour episodes, was commissioned by popular demand and began broadcast on Sunday 5 November 2006 at 11:10pm, with episodes once again available on the BBC's website. A third series consisting of eighteen weekly 11-minute online episodes began in December 2007, with three half-hour TV specials episodes also being produced. A Christmas special aired on 23 December 2007. A fourth series of the show was announced on 31 December 2015. Series 4 began in March 2016, and consists of six online episodes and one televised special. Gaiden (外伝) is a Japanese word meaning 'side-story', a reference to the show's relationship to its predecessor Consolevania.