In Japan, Sesshō (摂政) was a title given to a regent who was named to act on behalf of either a child emperor before his coming of age, or an empress regnant. The Kampaku (関白) was theoretically a sort of chief advisor for the Emperor, but was in practice the title of both first secretary and regent who assisted an adult Emperor. The duties of the Sesshō and Kampaku were to convey to the Emperor the policies formulated by the Sadaijin and other senior officials of the Daijō-kan , and to convey the Emperor's decisions to them. As regents of the Emperor, the Sesshō and Kampaku sometimes made decisions on behalf of the Emperor, but their positions were not defined by law and they had no specific political authority. The two titles were collectively known as sekkan (摂関), and the families that exclusively held the titles were called sekkan-ke.

The emperor of Japan or Tennō , literally "ruler from heaven" or "heavenly sovereign", is the hereditary monarch and head of state of Japan. The emperor is defined by the Constitution of Japan as the symbol of the Japanese state and the unity of the Japanese people, his position deriving from "the will of the people with whom resides sovereign power". The Imperial Household Law governs the line of imperial succession. Pursuant to his constitutional role as a national symbol, and in accordance with rulings by the Supreme Court of Japan, the emperor is personally immune from prosecution. By virtue of his position as the head of the Imperial House, the emperor is also recognized as the head of the Shinto religion, which holds him to be the direct descendant of the sun goddess Amaterasu. According to tradition, the office of emperor was created in the 7th century BC, but the first historically verifiable emperors appear around the 5th or 6th centuries AD.