Okuiri is a commentary on the Tale of Genji written by FUJIWARA no Sadaie. It is said to have been written around 1233. It is the next oldest commentary on the Tale of Genji after the 'Genji Shaku,' which is considered to be the oldest, and was later recognized for its importance. It is one chapter in total.
Originally, FUJIWARA no Sadaie added various notes to the end of the text of the Tale of Genji manuscript that he himself had copied as a shohon (a verified text).
That was the origin of the name 'Okuiri.'
Even nowadays, there survive a lot of manuscripts with this 'Okuiri' at the end of each volume. Kikan IKEDA mentions that when judging whether a manuscript of the Tale of Genji is an Aobyoshi-bon manuscript, those that are descended from FUJIWARA no Sadaie's shohon, it is a requirement for the manuscript to have this 'Okuiri' in it.
When FUJIWARA no Sadaie lent a manuscript to someone, those annotations were copied and spread in public without his permission, and on top of that, some people criticized his opinions.
Because of that, he removed them from the manuscript and made them into a book. It is said that when he did so, part of the text such as poems were lost.
There are two types of Okuiri, 'the first Okuiri' (the first version) that was written in the Oshima-bon and the Meiyurinmo-bon manuscripts, and 'the second Okuiri' (the second version) that was included in Sadaie's own hand-written manuscript. In general, the second version covers more details than the first. As to which version was the earlier one, some theories say that the first version came into existence earlier and others that the second version was actually written first.
In Okuiri, he regards the earlier commentary, the 'Genji Shaku,' as important, and quotes a lot of opinions from it in many sections. He follows the opinions of the Genji Shaku in many cases, but not all the time. There are also some cases where he criticizes its opinions.