The Daijō-daijin or Dajō-daijin[1] (太政大臣, "Chancellor of the Realm") was the head of the Daijō-kan (太政官, Council of State) during and after the Nara period and briefly under the Meiji Constitution.

Emperor Tenji's favorite son, Prince Ōtomo, was the first to have been accorded the title of Daijō-daijin during the reign of his father.

[3] At a time when the Emperor and the nobility held real power, the Daijō-daijin was the highest position in the Daijō-kan, the central organ of the state.

Although the position continued in name until 1885, by the beginning of the 12th century, the office was essentially powerless, and was often vacant for lengthy periods.

[6][7] During the Kamakura period (1185-1333), high-ranking positions at the Daijō-kan, such as Sadaijin, and Udaijin, also became honorary titles bestowed by the emperor on members of the warrior class.