was the collective name for the four cadet branches of the Imperial Household of Japan, entitled to provide a successor to the Chrysanthemum throne if the main line failed to produce an heir. The heads of these royal houses held the title of , regardless of their genealogical distance from the reigning Emperor, as the term seshuu in their designation meant that they were eligible for succession.
This proved to be a fortunate decision, as in 1428, the son of the 2nd Prince Fushimi-no-miya ascended the throne as Emperor Go-Hanazono.
In the Edo period, three additional seshuu shinnōke households were created by the Tokugawa bakufu, in conscious imitation of the
However, aside from Emperor Go-Hanazono, the only time a member of the seshuu shinnōke ascended to the throne was in 1779, when the son of Prince Kan'in-no-miya Sukehito became Emperor Kokaku.
Within the seshuu shinnōke households, younger non-heir sons (who were titled ), had two career options. They could "descend" to subject status with a surname such as Minamoto or Taira, and serve as a government official, or they could enter the Buddhist priesthood, generally as the head of one of the monzeki temples in and around Kyoto. During the Edo period, the latter practice became almost universal. Non-heir sons who entered the priesthood were styled , and were automatically excluded from the succession, but could be recalled to "secular" status (and thus reinstated as potential successors) as need arose. Daughters were frequently used as pawns to cement matrimonial alliances with kuge, daimyō or the Tokugawa houses. Unwed daughters often became Buddhist nuns.
The Katsura-no-miya and Arisugawa-no-miya houses died out in 1881 and 1913, respectively. The sixteenth son of Prince Kuniie, the twentieth head of the Fushimi-no-miya, succeeded to the Kan'in-no-miya house in 1875.