This is called the famous “Horse Riders Theory”. It is the million-dollar mystery that is at the centre of archaeology in Japan today. It is the crux of the controversy surrounding questions about the origins of the imperial family, of how “Japanese” Japanese really are, or how Korean Japanese are.
Sometime in the 4th century, horse trappings and ornaments began to be buried as grave goods in the burial tombs of kings and tribal clan chiefs in Japan. The emergence of many very large mounded tombs together with the horse related grave goods suggested to historians that a powerful warrior clan or group of clans had emerged in the Yamato region and then spread their power to other parts of the country by force and aided by superior horse technology. The earliest historical chronicles suggested that this paramount clan (possibly alliance of clans) had subdued other local chieftains in a series of bloody wars.
According to the Nihon shoki, these conquering groups had “clad themselves in armor and helmet and gone across hills and waters, [and] sparing no time for rest…conquered the fifty-five countries of hairy men in the east, and brought to their knees the sixty-six countries of various barbarians in the west.” This has led some historians and experts to believe that horse-riding and conquering warriors arrived in Japan blazing their way and subduing the land.
By the sixth century, this paramount chieftain was called okimi or “the great lord” had emerged … historians refer to him as the Yamato ruler.
The horse-rider theory
The horse-rider theory (kiba minzoku setsu) was proposed by Egami Namio, a professor of Asian history at Tokyo University. It generally holds that the unified state was founded by a group of horse-riding warriors, who entered or invaded the Japanese islands, conquered the native rulers, and established themselves as Japan’s ruling class. Egami examined the Kofun Tombs and noted that tombs of the Late Tomb (5th – 6th centuries) period contained items different from the previous centuries: weapons, armor, horse trappings and ceramic figurines of warriors and other persons which Egami said were “realistic, warlike, baronial, horse-riding and North Asian” looking. Egami also thought the “Chin king” identified in Chinese sources was of horse rider origin connected with Puyo or Koguryo, and that Emperor Sujin was linked to or descended from the Chin king line.
Many variations of this horse-rider theory have developed since Egami’s time. The theories differ on the origin and ethnic identity of those invading warriors from the Asian continent, on the time of their arrival in Japan, the route they took and the way they came to dominate Japanese society.
In one variation – an ethnologist Oka Masao examined the cultural traits of the Kofun period peoples and identified four different cultures, the last of which he believed was the “imperial race” that dominated Japan during the Kofun period had originated in eastern Manchuria as a mixed herding and farming people and that in the 2nd and 3rd century it had moved through the Korean peninsula and into Japan. He believed that they were culturally and ethnically closely related to the ancient Puyo and Koguryo states on the Korean peninsula.
In another variation of the horse-rider Theory, Gary Ledyard agreed with Egami that Emperor Sujin was very likely the first “Korean” ruler of Japanese territory. But Ledyard differed from Egami in that he thought that Sujin could not have been a horseriding conqueror. He believed it was more likely that Sujin led a peaceful migration of ethnic Wa people who were living in Kaya, the southern part of Korea in the 4th century, who under threat from horseriding Puyo tribesmen from the north, wished to seek santuary with their relatives on Kyushu Island.
Many Japanese archaeologists as well as foreign archaeologists disagree with the horse rider theory. Foremost of critics is J. Edward Kidder, an American archaeologist with 20 years experience in Japan – who says that the timing is all wrong.
There have been too few trappings associated with horseriding – merely a few trappings from early 5th century nobleman’s tombs. They are also all of cruder quality resembling the more backward technology of Silla than of the more militarily advanced Paekche or Koguryo. The surge in numbers of excavated horseriding gear and haniwa clay figurines are from the late 5th century which suggests to Kidder that the horseriders came with a second wave of immigrants. The archaeological evidence suggests that the foreign migrants filtered in, eventually united with local populations and dominated elite positions and the ranks of nobility. Kidder thinks that they migrated more like modern-day refugees in small groups and families, rather than in conquering droves like the Vikings. As the migrants brought with them advanced skills and technology so that they rose quickly to positions of leadership and dominance.
Kidder also points out that Emperor Ojin appeared unlikely to have been a horseman, instead he was more like a farmer — as the Kojiki chronicles describes the emperor’s preoccupation with building ponds and roads. Also, the Kojiki mentioned that a pair of horses were sent as a gift to the Japanese king but they could not find anybody who knew how to care for the horses — if the king had been a horseman, he would have had equestrian help in his entourage who knew what to do with the horses. Kidder makes a further observation that the first emperor who is actually described riding a horse comes two reigns after Ojin but he is described as having a groom who holds the bit while he rides, and so was hardly likely to have been a warrior horseman. Kidder asserts that it is only at the end of the Ojin line of kings that one of the kings is described as riding off to hunt. Finally, he concludes it is only with the much later Emperor Keitai (507-538) that horse riding skill and technology appears to have caught up with that of the Korean peninsula’s.
Supporting his view is anthropologist Gina Barnes who asserts that Japan had already organized itself into a state by the time the horse riders actually rise to prominence. Political unification of the whole southern Japan coincided with the reign of Emperor Keitai and his successors in the 6th century, so that it could be concluded that the rise of the horseriding nobility merely helped to peak the development of the Yamato state, but did not bring it about.
There are others like Wontack Hong who asserts that taking in together all the the host of archaeological evidence as well as ancient texts, that the influxes and influence of Korean migrants is incontrovertibly clear, and that a case might be made that earlier as well as later arrivals from Paekche form the most prominent part of the Korean contribution to the ruling elite of Japan.
Kidder says that nothing can be settled for sure except when the imperial tombs are fully excavated for a full scrutiny of the equestrian grave goods that can be expected to turn up then.
J. E. Kidder 1985, ‘The archaeology of the early horse-riders in Japan’ TASJ (3rd series) 20: 89-123
G. Ledyard 1975, ‘Galloping along with the horseriders: looking for the founders of Japan’, JJS 1: 217-254
Kim Song-ho 1985, ‘Origins of the Japanese polity: a textual reconsideration of the horse-rider theory’, Korea Journal 25.12: 4-23
J. R. Kirkland 1981, ‘The horseriders in Korea: a critical evaluation of a historical theory’, Korean Studies 5:109-128
W. W. Farris 1992, Heavenly warriors: the evolution of Japan’s military, 500-1300 (Cambridge, Mass.: Council of East Asian Studies, Harvard University)
W. Edwards 1983, ‘Event and process in the founding of Japan: the Horserider Theory in archeological perspective’, JJS 9: 265-95
M. Como 2007, ‘Horses, dragons, and disease in Nara Japan’, JJRS34: 393-415
John H. Douglas, ‘Suggestions that the Japanese Emperor may be descended from mounted Korean conquerors have made archeology a hot political subject’ Association for Asian Research 11/28/2004
G. L. Barnes 1988, Protohistoric Yamato: archaeology of the first Japanese state (Center for Japanese Studies/Museum of Anthropology, University of Michigan, Ann Arbor)
G. L. Barnes 2003, State formation in Japan: essays on Yayoi and Korun period archaeology (London: RoutledgeCurzon)
G. L. Barnes 2007, State formation in Japan: emergence of a 4th-century ruling elite (London: Routledge)
G.L. Barnes ‘The Rise of China, Korea and Japan: The Rise of Civilization in East Asia’ (London: Thames and Hudson, 1993)
Wontack Hong ‘Yayoi Wave, Kofun Wave, and Timing: the Formation of the Japanese People and the Japanese Language’ Korean Studies, Vol. 29, 2005 (pdf version)
J. R. Piggott 1997, The emergence of Japanese kingship (Stanford: Stanford University Press)