天皇以前の古代氏族の伝承Ancient Clan Traditions Predating the Emperor

The beacon of national conquest ignited in ancient Yamato (present-day southern Nara Prefecture) began with an imperial court upholding an imperial lineage; at its roots lay a significant migration and blending of ancient peoples, whose history has largely been lost, yet those who later gained authority as clans advanced while encompassing these historical elements.

Particularly, due to Japan’s prolonged absence of written language, no documents related to ancient Japan existed, and even after the introduction of written culture via Buddhism from China, the documents produced were frequently lost or disappeared into obscurity amid rapidly changing rulers and political upheaval.

Consequently, the oldest surviving Japanese document today is the Kojiki, compiled in 712 CE; thus, compared to regions such as China, the systematic utilization of written culture by the Japanese imperial court was relatively limited and brief. Over roughly two centuries from this period, only fragmented and complex traces of clans that held a certain level of authority remain.

Amid this backdrop, the rise of Buddhism triggered the sweeping away of old powers in Yamato, significantly reshaping the dynamics between court clans. This upheaval allowed the Soga clan, which drew on ties with the many people who had come from across the sea and lived in the Yamato region, to ascend prominently, marking a significant turning point. However, it’s important to note that rather than equating this with Japanese history as a whole, it should be viewed as a very localized history. Although frequently identified in Japan as representative of national history, it pertains specifically to power struggles within the southern Nara Basin region of Yamato, along with limited factions in western Japan that had interactions, allegiances, or alliances with them.

During this turbulent period, the Mononobe clan, who had historically supported successive emperors both militarily and religiously, suffered defeat by the Soga clan and virtually vanished from the historical forefront. The Mononobe clan’s origins date back significantly earlier, as they were among the dominant forces from pre-literate times, rooted in the leadership of a composite group that gained considerable influence within certain parts of Yamato. Although the exact location of their base remains unclear, a shrine associated with the Mononobe clan, Isonokami Shrine, was possibly later erected in present-day Tenri City, and is known as one of Japan’s oldest shrines.

In reality, pinpointing the origins of shrines like these is inherently challenging, but at the very least, this area can be regarded as the origin place of groups connected to the Mononobe clan. Moreover, before Kamuyamato Iwarehiko (神倭伊波礼比古命) from Hyuga (present-day coastal Miyazaki Prefecture) carried out his eastern conquest, took control of Yamato, and ascended as the first emperor—Emperor Jinmu (神武天皇)—at the site of Kashihara Shrine in Kashihara City, Nara Prefecture, the Mononobe clan had already held authority over the region. However, even in this case, if we provisionally define ancient Yamato as the southern-central part of today’s Nara Basin, their actual rule only extended to its eastern side.

Indeed, the western side was governed by the equally ancient Katsuragi clan, and the southern area was likely controlled by yet another distinct clan. Thus, I feel that the concept of ancient Japanese history itself has been used to this day under extremely ambiguous definitions. Observing the movements of the Soga clan, who later expanded their power following Buddhism’s arrival, it is clear they originated from Asuka in southern Yamato (present-day Nara Prefecture), reinforcing my belief that, at least as of the 6th century, Yamato was still a land of competing warlords.

However, the major ancient clans holding influence and competing within Yamato even before Emperor Jinmu’s enthronement at Kashihara likely possessed considerably older roots than Kamuyamato Iwarehiko’s lineage from Hyuga, suggesting they maintained highly distinctive beliefs, traditions, and social structures. Indeed, the Katsuragi clan has long been thought to have been shaped by crossings from the continent, with archaeological evidence pointing to traces of exchange across the sea.

In such a remarkably complicated era, it is hardly surprising that the Mononobe clan, who later rose prominently within Shinto contexts, possessed numerous traditions distinct from those of the imperial lineage.

Historically, the Nihon Shoki, compiled in 720 CE, attracted far greater historical attention than the earlier Kojiki. At the time, Japan was already deeply engaged diplomatically with China, thus Nihon Shoki was deliberately compiled according to the historical framework of Chinese imperial chronicles. As a result, Nihon Shoki enjoyed an unparalleled status and long remained the primary authoritative history of Japan.

This prevailing tradition shifted dramatically due to Edo-period scholars, notably Norinaga Motoori and his Kojikiden. Completed by Norinaga in 1798 and published progressively from 1790 to 1822, Kojikiden significantly elevated the status of the Kojiki. Nevertheless, it is worth noting that the dominance of Nihon Shoki persisted for over a millennium, until at least the early 19th century.

Yet, since the Kojiki itself dates to a relatively recent 712 CE, and considering the numerous clans within Yamato alone, we must acknowledge the likelihood of even older texts or oral traditions. Within this context, the Sendai Kuji Hongi (先代旧事本紀) has been historically significant, as this book compiled the ancient traditions of the Mononobe clan and, viewed from certain perspectives, has sometimes been considered Japan’s earliest text.

Although the Sendai Kuji Hongi was formally compiled around the early 9th century—thus later than Kojiki and Nihon Shoki—its contents and quality suggest it merely underwent textual compilation later, while its origins clearly date back considerably further. When examining these three texts—Kojiki, Nihon Shoki, and Sendai Kuji Hongi—the debate over which is the oldest emerges inevitably. Personally, I consider such arguments ultimately fruitless, as the real issue lies elsewhere.

The Sendai Kuji Hongi contains many intriguing passages, but because the Mononobe clan later submitted to the Hyuga lineage of Kamuyamato Iwarehiko (the imperial lineage), the text underwent external adaptations to venerate the emperor, making it challenging to discern the most ancient layers. However, it explicitly states that the Mononobe clan historically possessed the “Tokusa no Kandakara” (十種神宝, “Ten Sacred Regalia”), rather than the “Sanshu no Jingi” (三種の神器, “Three Imperial Regalia”) that emperors traditionally inherited.

In other words, before the imperial tradition of the Three Regalia, the Mononobe lineage preserved the Ten Treasures, which played an extremely vital role in Yamato’s authority. Recognizing this is crucial before further examining the nature of these Ten Treasures. Both Kojiki and Nihon Shoki show deliberate efforts to avoid addressing these complex issues directly, and similarly, the Sendai Kuji Hongi reveals noticeable accommodations toward imperial legitimacy. Consequently, interpretations can vary significantly based on the researcher’s stance.

Yet, without at least a basic understanding of the Mononobe clan, one cannot adequately grasp why the Soga clan’s rise, closely tied to the ascendancy of Buddhism, occurred within the Yamato court. Interestingly, despite the Mononobe clan likely having Yamato as their central base, their historical traces span across the entire country. In the next article, I will delve deeper into understanding the Mononobe clan from this perspective.

Below is an image from a manuscript of Sendai Kuji Hongi produced during the Edo period, which I recently had the opportunity to examine.