Ōjin Tennō, First Historical Emperor of Japan, Reigns

Ōjin was the first Japanese emperor who clearly was not legendary but an actual historical figure, and his reign saw a consolidation of power and economic and cultural development

Summary of Event

Ōjin Tennō, that is, Emperor Ōjin (also known as Homuda or Homutawake no Mikoto before his death), is the first such ruler who is actually a historical person. Although the oldest surviving written accounts of his reign, the Kojiki (712 c.e.; Records of Ancient Matters, 1883) and the Nihon shoki (compiled 720 c.e.; Nihongi: Chronicles of Japan from the Earliest Times to a.d.
697, 1896) still include some events that are either purely mythical, or a mix of legend and history, scholars agree that Ōjin lived and ruled Japan, albeit much later than these eighth century sources calculated. His reign thus marks the shift of protohistorical to historical Japan. Ōjin Tennō
Kaminaga Hime

Contemporary scholars have an inkling that Ōjin was a relative outsider who took over rule in the Yamato region of Japan and established his own reign there in one of the cradles of Japanese civilization. The ancient Yamato region encompasses the fertile Nara plain and is in the part of Japan’s central island of Honshū where the modern cities of Nara, Ōsaka, and Kobe are located, as well as the ancient shrine of Ise, dedicated to the emperor’s mythical ancestor, the sun goddess Amaterasu.

Some historians who subscribe to the hotly disputed “horse rider theory” even believe that Ōjin was part of this hypothetical Asian people theorized to have conquered Japan because of their superior weapons technology around the fourth century c.e. However, most historians believe that the indigenous Yayoi culture of Yamato and Kyūshū evolved to a higher state without outside invaders and that Ōjin was a member of this civilization.

According to tradition, Ōjin assumed the imperial throne as the fifteenth of Japan’s emperors in the year 270 c.e. About his real parents, nothing is known. However, myth has it that he was born to the legendary Empress Jingū (also known as Jingō) in 271, a few months after his father, the legendary fourteenth emperor Chūai, had either died in battle in Kyūshū or succumbed to a sudden illness. For the next sixty-nine years, until her death, his mother, Jingū, ruled as a regent, refusing to let her son be enthroned.

As emperor, Ōjin’s children became imperial princes and princesses, and many noble families of the seventh and eighth century later claimed one of them as their genuine first ancestor. Thus, the sources spend considerable attention to his ample offspring. Altogether, Ōjin had either twenty or twenty-six children. They were born to him by his wife, Empress Nakatsuhime, and his imperial concubines, two of whom were the younger sisters of the empress.

In the first years of his reign, Ōjin consolidated his power and dedicated himself to domestic politics. He used the workforce of tributary people to build roads and ponds, improving the Yamato region. He also organized the be, or guilds, of the fishermen and gamekeepers, securing a food supply for his domain. As such, Ōjin stands out compared with most other emperors, who performed fewer practical tasks and concerned themselves mostly with religious ceremonies.

Ōjin also became involved in foreign affairs in Korea. The Japanese were pursuing interests of their own and intervened in the affairs of the three Korean kingdoms of the period. Japanese and Korean sources vary considerably about the nature of these struggles and their exact date. Japanese tradition, for example, has it that Sinsă, the king of Paekje, disrespected Ōjin and was killed by his own people to atone for this transgression in 272 c.e. A Korean source states that Sinsă died in his traveling palace while hunting, in the year 392. Although the Korean date is believed to be correct, the nature of the king’s death is still subject to historical debate.

Ōjin continued his program of domestic improvements, often with foreign labor sent as tribute; shipbuilding; and consolidation of his rule. There were also intrigues among the nobles, such as when Takechi no Sukune was accused by his own brother of planning to usurp the throne. Sent to subdue the southwestern Japanese island of Kyūshū, Takechi returned to the palace to defend himself. A judgment by ordeal involving boiling water was won by Takechi, but the emperor prevented him from killing his brother, indicating Ōjin’s emphasis on domestic peace.

The emperor’s private life fascinated his contemporaries. After falling in love with the beautiful Kaminaga Hime in 282 c.e., Ōjin nevertheless yielded the young woman to his favorite son Ohosazaki no Mikoto (later the emperor Nintoku). He presented her to his son at a special banquet, and father and son expressed their desire in poems recorded for eternity. When Kaminaga responded to Ohosazaki without resistance, his status at court rose accordingly. Later, Ōjin allowed his beloved concubine Yehime, whom he had romanced with songs reminiscent of the songs of Salomon in the Bible, to visit her parents. Thus he showed humanity to his subjects.

Ōjin’s efforts at improving Yamato civilization also gained from his desire to have skilled professionals sent to Japan from Korea as tribute. The Korean seamstress Maketsu founded an important trade school, and the learned scribe Wani introduced writing to Japan. Historically, the Japanese acquired writing through the Korean scribe Wani from the Chinese around 404 c.e., even though the Japanese traditional account uses the older, incorrect date of 284. By using Chinese characters to correspond phonetically to spoken Japanese, Japan finally became literate, a key event of Ōjin’s reign.

Throughout his remaining years, Ōjin continued to intervene in Korea, occasionally sending Japanese troops to install his Korean protégés as kings there. He also demanded skilled immigrants to improve Japan’s manufacture and infrastructure.

At the end, Ōjin gave clear preferences to Ohosazaki. Even as he appointed another son as heir apparent, he gave Ohosazaki a powerful position of his own, from which he would eventually become the emperor Nintoku. When Ōjin died, in 310 according to legend, he left behind an empire of considerable power.


There may be a certain irony in the fact that later generations would make Ōjin the god of war, called Yahata or Hachiman—for his most enduring accomplishments lie in improving the domestic situation of his empire and in introducting writing to Japan. His interventions in Korean politics brought Ōjin many skillful immigrants from this area. Traditionally, his reign also provided Japan’s noble houses with many illustrious ancestors to claim for themselves, solidifying their position in Japan’s rank-conscious feudal society.

Indicative of the power, resources, and skills of the emperors of Yamato of Ōjin’s time are the many impressive burial mounds of the period. One of the earliest and largest mausoleums, in Habikino in Ōsaka prefecture, is traditionally believed to be Ōjin’s tomb. Like many of the others, it is shaped like a keyhole lying on the earth. It possesses three tiers, two moats, and two dikes. It is 1,362 feet (415 meters) long and rises over the plain landscape. Ōjin and his contemporaries’ graves gave the period of his reign its name, Kofun, which is Japanese for keyhole.

With Ōjin, Japanese imperial history leaves the realm of legend and enters that of history. Although there are still shrines in Japan venerating this emperor as the god of war, it is clear that he was a real person. His emphasis on domestic development and the improvement of the skills of his people advanced his nation, even though his office would become much more ceremonial in the decades and centuries to come, until the Meiji Restoration of 1868. Ōjin’s kindness to his concubine Yehime is remembered as an important personal trait of this emperor.

Further Reading

  • Aston, W. G., trans. Nihongi: Chronicles of Japan. London: George Allen and Unwind, 1956. Reprint of the original 1896 text. Still the only translation of this Japanese text, compiled in 710 and also called Nihon Shoki, which contains one of the two original accounts of Ōjin’s reign.
  • Brown, Delmer M., ed. Ancient Japan. Vol. 1 in The Cambridge History of Japan. New York: Cambridge University Press, 1993. A collection of contemporary essays covering the latest scholarship on the rise of early imperial Japan, with an interesting reflection on ancient Japanese historical consciousness; discusses the historical facts of Ōjin’s reign.
  • Philippi, Donald L., trans. Kojiki. Princeton, N.J.: Princeton University Press, 1968. English translation of the first surviving Japanese account of Ōjin’s reign, compiled in 712. The reader has to get used to Philippi’s unique style of transcribing ancient Japanese names into Roman letters, which alters the spelling of most, but this is the only English text of the Japanese original.
  • Reischauer, Robert Karl. Early Japanese History: Part A. Princeton University Press, 1937. Reprint. Gloucester, Mass.: Peter Smith, 1967. A pre-World War II compilation of Japanese sources telling of mostly legendary events, including those that occurred during Ōjin’s reign.
  • Sansom, George B. A History of Japan to 1334. Stanford, Calif.: Stanford University Press, 1958. Still valuable study of the earliest, legendary period of Japanese history.

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