udaijin

Udaijin (右大臣), literally "Minister of the Right," was a high-ranking official in the imperial court of Japan and a member of the Daijō-kan, the Council of State, during the Nara and Heian periods. The office was one of the senior positions in the government and was part of the system established by the ritsuryō codes.

In the court hierarchy, the udaijin ranked below the sadaijin (Minister of the Left) and above the naidaijin (Minister of the Center), with the daijō-daijin (Grand Minister of State) higher still. The office was typically filled by a member of the kuge, the court nobility, and its holder was among the top counselors to the emperor.

The udaijin was entrusted with advising the emperor and handling state affairs routed through the Ministry of the Right. While the Daijō-kan defined official responsibilities, actual duties varied over time; the udaijin often worked in coordination with the sadaijin and oversaw aspects of governance assigned to the right-hand branch of the government. Senior bureaucrats such as the sadaijin, udaijin, naidaijin, and various counselors played key roles in political decision-making, ceremonies, and court administration.

During the Heian period, many udaijin were connected to the powerful Fujiwara clan, which used the office to extend influence over court politics and regency. As political power shifted toward warrior rulers in the late medieval era, the practical authority of the Daijō-kan and its ministers weakened, and the title gradually became more ceremonial. After the Meiji Restoration, the old court offices were restructured in line with modern government institutions.