Asuka Kiyomihara Code in the context of "Dajōkan"

Minister of the Right (右大臣, Udaijin) was a government position in Japan during the Asuka to Meiji era. The position was consolidated in the Taihō Code of 701. The Asuka Kiyomihara Code of 689 marks the initial appearance of the Udaijin in the context of a central administrative body called the Daijō-kan (Council of State). This early Daijō-kan was composed of the three ministers—the Daijō-daijin (Chancellor), the Sadaijin (Minister of the Left) and the Udaijin. The Udaijin was the Junior Minister of State, overseeing all branches of the Daijō-kan. He would be the deputy of the Sadaijin.

From the Kamakura period (1185–1333), when the warrior class came to power in Japan, this imperial court position became an honorary position with no real authority. Oda Nobunaga, who was a powerful daimyo in the Azuchi-Momoyama period, was a daimyo who held this imperial court position. This was the first time since Minamoto no Sanetomo in 1218 that a member of the warrior class had been appointed Udaijin. Previously, the only warrior class members appointed to higher positions than Udaijin were Taira no Kiyomori and Ashikaga Yoshimitsu as Daijō-daijin, and Ashikaga Yoshinori and Ashikaga Yoshimasa as Sadaijin. The warrior class was able to use the high imperial court positions of Daijō-daijin, Sadaijin, and Udaijin, which had originally belonged to the nobility, as a means of establishing their own authority.

The Minister of the Left (左大臣, Sadaijin) was a government position in Japan during the Asuka to Meiji era. The Asuka Kiyomihara Code of 689 marks the initial appearance of the Sadaijin in the context of a central administrative body called the Daijō-kan (太政官, Council of State). This early Daijō-kan was composed of the three ministers—the Daijō-daijin (太政大臣, Chancellor of the Realm), the Sadaijin and the Udaijin (右大臣, Minister of the Right). The position was consolidated in the Taihō Code of 702.　In Yamto kotoba（ヤマト言葉）, it is also called "Ohoi-Mauchi-Kimi"於保伊萬宇智岐美.

When the Emperor and the nobility held real power, the Sadaijin was the highest permanent position in the Daijō-kan, the central organ of the state. The higher-ranking 'Daijō-daijin was not a permanent position, but was only appointed when a suitable person was found.The Sadaijin was the Senior Minister of State, overseeing all functions of government with the Udaijin as his deputy.

The Ōmi Code (近江令, ōmiryō) are a collection of governing rules compiled in 668AD, and the first collection of Ritsuryō laws in classical Japan. These laws were compiled by Fujiwara no Kamatari under the order of Emperor Tenji. This collection of laws is now lost and its disputed existence is supported only by short references in later documents (among which the Tōshi Kaden, a history of the Fujiwara). It is furthermore missing from the Nihon Shoki.

The Code, consisting of 22 volumes, was promulgated in the last year of Tenji's reign. This legal codification is no longer extant, but it is said to have been refined in what is known as the Asuka Kiyomihara ritsu-ryō of 689; and these are understood to have been a forerunner of the Taihō ritsu-ryō of 701.