Insei or 'cloistered government' describes the strategy of emperors during the late Heian Period (794-1185 CE) in ancient Japan where they abdicated in favour of a chosen heir yet still ruled in some capacity, typically after retiring to a Buddhist monastery, hence the reference to a cloister. The emperors took such measures to guard against themselves and their successor being dominated by the powerful ruling families of the period, especially members of the Fujiwara clan, who sought to place their own supporters on the imperial throne. Although successfully employed by several emperors, two of the unfortunate consequences of the strategy were that the provinces became more remote from government control and the rivalries for power in Japan heightened to such a degree that a greater militarisation of politics eventually led to a complete overthrow of government and long-lasting rule by the shoguns in the medieval period.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/1106/insei-cloistered-government-in-ancient-japan/.