馬はいつ日本に来たのかWhen Did Horses Arrive in Japan?

As the relationship between samurai and horses in the Sengoku period draws fresh attention with the popularity of works such as Shogun, many people may have the impression that horses have existed in Japan since ancient times. But according to current scholarship, the horse was not a native animal of ancient Japan; it is thought to be an animal that came from abroad along with people who crossed the sea. When, then, did horses reach Japan, and how did they take root?

At present, no firm evidence has been found that horses existed in Japan's Jomon and Yayoi periods, which correspond to prehistory. At the same time, there are a few cases in which fossils and teeth of ancient horses have been found, so the question is still not settled. The tooth of a small horse found in a Pleistocene layer about 28,000 years old became a great topic in particular. This suggests that horses may have crossed from the Eurasian continent, which was connected by land in the Ice Age, and lived in the archipelago, but the oldest horses are now thought to have died out at an early stage and not to have existed after the Jomon period.

The oldest written record about horses in Japan lies not on the Japanese side but on the Chinese side, because Japan had no writing culture at the time. According to the Records of Wei: Account of the Wa People (魏志倭人伝), a precious source that touches on the Japan of about the third century, an envoy of Wei sent to Japan stated plainly that “there are no horses in Japan.” The text also records that there were no cattle.

Because Japanese and horses had a deep relationship through the thousand years and more that followed, a persistent counterargument arose in the twentieth century that this record surveyed only a limited area and does not mean that horses were absent from ancient Japan as a whole. But the credibility of this source has been reinforced, first, by archaeology.

Archaeologists have surveyed many places through the twentieth century, but no trace showing certain evidence that horses existed in Japan has been found in Jomon or Yayoi sites. I too have visited Jomon and Yayoi sites and museums around the country, and found no trace of horses.

Moreover, after the archaeological results of the twentieth century, in the twenty-first the development of DNA lineage analysis has supported the possibility that Japan's native horses did not exist in prehistory. When, then, did horses come to exist in Japan? That is the mysterious fifth century.

When the Yayoi period, in which the presence of horses is uncertain, ends and the new Kofun period begins, the situation changes at once. Horse bones and tack begin to be unearthed in large quantities from the tombs and sites of this age. This shows that after the Kofun period began, horses, which had not existed before, appeared across Japan and spread at once. Horse tack in particular begins to appear as grave goods from the late fourth to the early fifth century and increases sharply through the fifth. Tack has been unearthed from more than 1,200 sites across the country, and more than a quarter are in Kyushu, close to the Korean Peninsula, followed by Kanto, Kinki and Chugoku.

In the late fifth century, many haniwa (埴輪), set around the tombs of kings in various places, came to be made in the shape of horses, and from the sixth century horse-shaped haniwa were lined up at tombs everywhere. Horse-shaped haniwa are a common find at about 300 sites across the country, more than half in Kanto, followed by Kinki and Kyushu. From these Chinese histories and this academic evidence, we can understand that horses came to Japan around the fifth century by way of the continent and the peninsula, and that full-scale horse breeding began afterward.

The Nihon Shoki (completed in 720), Japan's oldest written history, records that when a woman called Okinagatarashihime (Empress Jingu), consort of an emperor in the third century, advanced to the Korean Peninsula, the king of ancient Silla presented horses. But Jingu's existence has long been doubted, and the view that she is a legendary figure is strong at present, so this is hardly used as a reference.

Setting that aside, horses appear in the Nihon Shoki in the late fifth century, and it is recorded that by then horses were bred at court. A record of 554 also notes that in a meeting with its ally Baekje (part of the Korean Peninsula), the Japanese side promised to send “1,000 reinforcements and 100 horses.” Astonishingly, in only about a century horses had increased enough to be exported to another country. From the sixth century there is also a record of horses used in Shinto rites, and this rite continues today as yabusame (流鏑馬), one of the quite old traditional cultures.

The movement accelerated further in the eighth century. In this age, when the foundations of a centralized system were laid in Japan, the court, strongly influenced by China, set up specialist posts to breed and manage horses for use in war for military purposes. This spread beyond the Kinki region, where the court then was, to neighboring areas and the Kanto region, and in 718 horses were presented to the court by tribes of the Tohoku region. This age became the foundation on which horses would later be joined to the age of the samurai.

From this basic background of ancient Japanese history, it is now generally accepted that the horse was not a native species of ancient Japan but an animal that arrived with people who crossed the sea in a particular age. People living the Jomon and Yayoi way of life must then have been struck with shock when, suddenly, from the fourth to the fifth century, new people appeared riding horses.

And indeed it is gradually becoming clear that life in the archipelago changed greatly through new people who appeared in a form never seen before. This is the new force that forms the Kofun period, and its characteristic is the use of the “horse” and “iron” in military affairs, which had not existed in Japan before. The Jomon and Yayoi ways of life, which had neither horse nor iron culture, had difficulty standing against them.

The great upheaval of mysterious ancient Japanese history is revealed for the first time by investigating this Kofun period. What on earth did they see? I will go on exploring that.