Dajo Hoo (Cloistered Retired Emperor) (太上法皇)
Dajo Hoo (also referred to as Daijo Hoo) is a retired emperor (Dajo Tenno) who became a priest. Otherwise, the title thereof. It is abbreviated as Hoo. However, there is no difference between the legal status of a Retired Emperor (Dajo Tenno who does not become a priest) and Hoo.
Although it is generally believed that Emperor Uda during the Heian period used this title for the first time, because "Shoku Nihongi" (Chronicles of Japan Continued) says that Emperor Shomu joined the ceremony to consecrate the Great Buddha at Todai-ji Temple under the title of Hoo after his abdication of the throne, its origin is not unified. Emperor Shirakawa, Emperor Toba, and Emperor Goshirakawa ruled the cloistered government as Hoo during the Heian period. Emperor Reigen during the Edo period was the last Dajo Hoo.