Kugyo-bunin is a historical material of Japan and the directory of successive personnel in the Imperial Court.
Each and every year from the time of the Emperor Jinmu to 1868, it listed names of those who held the rank of Jusanmi (Junior Third Rank) or higher which were the so-called Kugyo (the top court officials) including Daijo-daijin (Grand Minister), Sessho Kampaku (regent and chief adviser to the Emperor), Sadaijin (the Minister of the Left), Udaijin (the Minister of the Right), Naidaijin (the Minister of the Interior), Dainagon (Major Counselor), Chunagon (Middle Counselor), Sangi (advisor on the Council of State), and Hisangi (advisor at large). Real family names were written on the list. The names of the Fujiwara families were abbreviated as 'FUJI XX' and were not written as 'FUJIWARA XX'. Below the names of each person, years of birth and death, personal records such as promotion and appointment were written in addition.
The authorship and the time when Kugyo-bunin came into existence has not yet been ascertained, but it is believed to be based on 'Rekiunki' and names had been added from the time of Konin. Establishment of Kugyo-bunin in the form of a book with a detailed personal record of the later years is believed to be around Owa to Shoryaku era. Note also that the entry on Hisangi is thought to have been added to sometime after the Chowa era.
This is the most coherent historical material on appointment, but some of its part is said to have been rewritten (appointment by retroactive date and so on) due to inaccuracy of the article from the early Heian period and for political reasons.
Therefore, there are cases where it does not correspond to the actual appointments