古事記の信憑性と欠史八代The Legitimacy of the Kojiki: Japan's Oldest Text and the Eight Undocumented Monarchs

Today, I look at how the historical credibility of the Kojiki, known as the oldest surviving book, has begun to waver, a matter tied to the theory of the “eight undocumented monarchs” (kesshi hachidai), which strikes a heavy blow at the theory of the emperor's unbroken line.

Emperor Jimmu is said to have first taken the throne in 660 BCE at Kashihara, in what is now southern Nara Prefecture. If we regard Jimmu as the first emperor, then for the theory of the unbroken line to hold, the existence of every emperor after him must naturally be confirmed in sequence.

Yet historical scholarship has pointed out that the emperors from the second to the ninth after Jimmu may not have existed. The Kojiki (completed in 712) and the Nihon Shoki (completed in 720) generally record that after Jimmu died, the following genealogy was handed down (dates of accession are all unknown for the ancient period):

2nd: Emperor Suizei

3rd: Emperor Annei

4th: Emperor Itoku

5th: Emperor Kosho

6th: Emperor Koan

7th: Emperor Korei

8th: Emperor Kogen

9th: Emperor Kaika

It has long been pointed out that the existence of these eight emperors is doubtful from the standpoint of historical scholarship, and they are said to have been very likely invented and added by someone in a much later age.

At present, drawing on records such as the Kojiki and Nihon Shoki and a number of old traditions, the existence of the tenth emperor, Sujin, is certain. Many deeds associated with Sujin are in fact handed down in southern Nara, and he has been placed among the most important figures in the history of the emperors.

Are the Kojiki and the Nihon Shoki, then, merely works invented by someone in a later age? Some extreme opinions see them that way. Let us first consider the standing of the Kojiki. It originates in a national project led by Emperor Tenmu himself, who gathered trusted retainers at court. Tenmu reigned from 673 to 686, but because coups over the right of succession followed one after another around his time, including his own, how accurate it is remains unknown.

What matters here is that Tenmu deliberately avoided writing these things down and compiling them into a book. Instead he had one of his retainers, Hieda no Are, thoroughly commit them to memory through recitation.

After Tenmu died, his empress, Jito (r. 690–697), took the throne. Next, Prince Kusakabe, Tenmu's son and the expected next emperor, died young, so Monmu (r. 697–707), born to Kusakabe and a daughter of Tenji (r. 668–672), regarded as Tenmu's elder brother, took the throne provisionally.

After Monmu came his mother, Empress Genmei (r. 707–715), who had a great influence on Japanese history. Without Genmei, neither the Kojiki nor the Nihon Shoki would exist.

Although she had laid the groundwork of the Kojiki in Tenmu's time, Genmei worried that the achievement would be lost when Hieda no Are, on whose recitation alone it depended, died. She therefore ordered a retainer, O no Yasumaro, to put the recitation of the still-living Hieda no Are into writing and present it to her.

So in 712 the Kojiki, produced by retainers led by Yasumaro, was presented to Genmei. At the same time, to bring Japan closer to the Chinese imperial system, she ordered the production of the Nihon Shoki as a national history, and it was presented in 720.

Interestingly, these important national projects spilled over into another important one: the making of the Fudoki.

She ordered local officials with close ties to the Yamato court (the center where the emperor and aristocrats ran politics, in today's southern Nara Prefecture) to gather the old traditions of their regions and leave them for later ages as books in the same way. Without this policy of Genmei, we could not know ancient Japanese history.

These accounts have been regarded as fact on the strength of the Nihon Shoki and have spread as the accepted view for most periods. In recent years, however, some scholars have been voicing the view that even this important historical fact should be reexamined.

Foremost among them is Sadakazu Fujii (b. 1942), professor emeritus at the University of Tokyo. His father, Sadafumi Fujii, a disciple of Shinobu Orikuchi, a leading figure of folklore studies, was a distinguished historian of Shinto, deeply versed in the complex history of Shinto from the Edo to the Meiji era. Sadakazu thus learned deep knowledge of Shinto from childhood.

He became active as a writer in the early 1970s, just as the student movements of the late 1960s subsided. Armed with the finest learning in classical Japanese of his day, he drew attention with his first book, an ambitious study of The Tale of Genji.

Living as a scholar while also working as a poet, he devoted his life to the historical study of Japanese monogatari (tales), and left overwhelming achievements. Fujii, more versed than anyone in ancient Japanese and widely familiar with myth, tradition, tale and poetry, put forward an important theory in 2022.

It is the theory that the important preface of the Kojiki, long taken to be Japan's oldest book, is the invention of someone in a later age.

That is, it was pointed out that reliance on the Kojiki preface, which says that on Genmei's order the retainer O no Yasumaro put Hieda no Are's recitation into writing, could collapse at a stroke.

What effect will this have on Japanese history? I will explore that in the coming articles.