The Shaku Nihongi (釈日本紀) is a piece of Japanese Literature dating to the 13th Century. This document preserves some of the Commentaries written concerning the Nihongi soon after its completion, the commentaries described as being written during the Eras Yōrō 714-724, Kōnin 810-824 and Engi 901-923.1
1. Aston. W.G. (1896) “Nihongi Volume 1: Chronicles of Japan from the Earliest Times to AD697”. Tuttle Publishing.
Check out Japan Archives, our Japanese History Podcast