'Shrine transfer'. Also go-sengu, or shikinen-gosenza-sai (special-year enshrinement rite) or similar. It refers to the practice of transferring a kami from one shrine building to another one which has been newly-built, or from the main shrine to an o-tabisho during a matsuri, or simply from one shrine to another in cases where the kami has two 'houses'. Before the Tokugawa period the practice of transferring a kami to a shrine in a private residence was also widespread. The best-known type of sengu is the shikinen sengu 'special ceremony-year transfer' carried out every twenty years at the Ise jingu, in which Amaterasu is transferred at dead of night to the new neighbouring shrine. The sengu procession is a profoundly dramatic and solemn ritual event marked by various taboos (imi).
See also Senko no gi. Other sengu at intervals of about a generation are carried out elsewhere, sometimes at shrines of quite small villages. The cost of periodic rebuilding is substantial and now has to be met (including at Ise) by voluntary contributions. Torches (taimatsu), lanterns (chochin) etc. may be used to suggest night-time even where the sengu ceremony actually takes place in daylight.
A Popular Dictionary of Shinto. Brian Bocking.