Takaakira was born as a prince of Emperor Daigo and is known for having been demoted to Dazai-fu (local government office in Kyushu region) in the Anna Incident after being promoted to Sadaijin (minister of the left) after demotion from nobility to subject. He is also said to have been one of the models of Hikaru Genji in "The Tale of Genji." Because Takaakira's house was on the side of Saikyu (west part of capital), which was unusual at the time, he was also known as 'Saikyu Sadaijin,' from which the book title was derived.
It is not known when the book was written, but some people say that one of the motivations to write it was to initiate Yusoku kojitsu to his son MINAMOTO no Toshikata who had been sent to Dazai-fu with him during the Anwa Incident. The book appears to have been enlarged and revised several times, and the first and the revised manuscripts exist. Moreover, there are parts that were improved (by MINAMOTO no Tsuneyori, according to a theory) after the death of Takaakira during the reign of the Emperor Goichijo, and it is considered that there were more than three lines of books with different contents and organizations. It is also considered that some contents of other books were mixed in while copying and that there are overlapping descriptions. As a result, there are different theories about how many volumes the book came in, but among the existing books, there is a book in 17 volumes and one in 18 volumes, although the record indicates various numbers including 4, 10, 15, and 16. It is considered that the book in 15 volumes was the original version by Takaakira, but it does not exist, and the book in 10 volumes was widely known as the rufu-bon (widely circulated edition), which had been sorted out and added kanmotsu (annotation of a book) instead.
Basically, the structure is divided into two parts: 'Annual' where annual events per month were lined up from January to December and 'Temporary' where descriptions are given about the events that took place on a temporary basis. Each description consists of the 'text' including notes inserted between the lines, and 'kanmotsu' comprised of many Tosho (superscription), bosho (傍書) (additions or supplements written by the side of the main texts), and book-end notes showing the sources of quotations from many books. It is an important historical material that provides in detail the contents and origins about the ceremonial rites of Imperial Court.
18 volumes of Kansubon (book in scroll style) possessed by Sonkeikaku-bunko Library (7 volumes of Annual, 10 volumes of Temporary, and 1 volume of catalogue, although one of the volumes of Annual and 4 volumes of Temporary overlap), 3 volumes of Kansubon possessed by Higashiyama Go-bunko collection (1 volume of the section on January of Annual and 2 volumes of Temporary), and 17 volumes of Kansubon in the collection of Imperial Household Archives (8 volumes of Annual, 9 volumes of Temporary, although 2 volumes of each were manuscripts from the Edo period) are among the known old manuscripts.