"Sendai no kuji" (Ancient matters of former ages) and "Honji" (Accounts of origin) in the introduction of "Kojiki" (The Records of Ancient Matters), and "Joko shoji" (matters of high antiquity) in the section of Emperor Tenmu's 10th year and 3rd month in "Nihonshoki" (Chronicles of Japan) are considered to be this book.
古事記序文にある『先代旧辞』（せんだいのくじ）及び『本辞』、日本書紀天武天皇10年3月条にある『上古諸事』はこの書のことと考えられている。