It is based on the explanatory note on the first part of the story of Susanoo's killing of the Yamata no Orochi (an eight-forked great serpent), which is described in the Chigi hongi (the original record of earthly deity worship) in the volume 4 of "The Sendai Kujihongi" (Ancient Japanese History) (although it is said to be false an apocryphal book that was submitted when lecturing on the Chronicles of Japan) that is quoted from the article on Soshimari described in book 10 of volume 20 of the "Wamyo ruijusho" (Japan's oldest dictionary of Chinese characters edited in the Heian period).
『和名類聚抄』二十巻本第10卷にある蘇志摩利の記述を引用した『先代旧事本紀』（日本紀講筵の際提出された偽書とされる）巻第四地祇本紀の素戔烏尊によるヤマタノオロチ退治の前段の分注記事による。