Since 'Emperor Otomo' was not found in "Chronicles of Japan" and "Kaifuso," it was considered that the conclusion was made based on some proofs, but details were unknown because the text was lost.
『書紀』と『懐風藻』に「大友帝」とは書かれていないから、何らかの論証を経た結論と思われるが、本文が失われているので内容不明である。