Jomon Culture and the Emishi
There had been speculation that many ethnic groups used to inhabit the islands during the Jomon period, roughly ten thousand years B.C. to about 300 B.C. (ending earlier depending on the region). What has been found confirms a much older hypothesis that there was basically one ethnic group, the Jomon, who resided on all the islands. The skeletal remains that date back before the Yayoi period, when the Japanese speakers began their expansion, have been of one dominant population group whether in Western Japan, the Tohoku or Hokkaido. The one cultural trait they shared was the type of pottery they produced marked by distinctive rope-like patterns called jomon doki that gave them their name.
In the latest research it is found that the transformation of the Jomon population occurred gradually as the Yayoi population identified with the Japanese speakers spread from northern Kyushu eastwards. Intermixing of the populations was widespread as intermediate skeletal types emerge in areas where the two populations came in contact with each other. However, over time, where these contacts occurred the Jomon population gradually changed to become more Yayoi in character indicating that the Yayoi began to outnumber the local Jomon population. Thus, the intermixing was heavily weighted towards the Yayoi population during the historical period particularly in western Japan since the Jomon people there were not as numerous.
One exception is in the southern Kyushu areas dominated by the Kumaso during ancient times. To this day the area around present-day Kagoshima has a population that is relatively unchanged since the Jomon, and have characteristics that are more related to the Ainu and Okinawans than to modern Japanese. This underlines the peril of making generalizations about the Japanese population in regards to the nation as a whole since there were local population histories that seem to defy them. Pockets where the Jomon were the majority remained into the historical period.
The modern Japanese population is thus mainly Yayoi in character with visible traces of Jomon mostly among recently absorbed populations such as the Ainu, and to a lesser extent, the people of the Tohoku. In the early years of Yayoi cultural diffusion there was not as sharp a division between the Yayoi and Jomon populations. This condition would only be possible if there was a cultural and economic change not a sudden ethnic one, and contradicts the notion that the incipient Yayoi culture was carried over by an immigrant group.
The physical evidence seems to point to cultural diffusion rather than an invasion, otherwise, there would be a replacement of one population over the other rather than a gradual change. Through time, as more East Asian immigrants were either absorbed or took over, these ethnic differences became more pronounced, and by the time of the Yamato kings ethnic conflict became endemic particularly with the Jomon in western Japan, and the Tohoku (see The Treatment of Natives in the Nihon shoki: the case of western Japan, above).
By the end of the Yayoi period and the beginnings of the Kofun period in the third century AD, the line between the Yayoi and the Jomon had increased particularly between the Kinai and eastern Japan northwards. The Yayoi population represented by the formative Japanese state known as Yamato had become mainly modern East Asian in appearance and ethnicity, similar to other Chinese, Koreans and northeast Asians while the Jomon population stayed the same, conserving much older ethnic traits. Why this happened is still inconclusive, but points to a much larger existing Jomon population in eastern and northern Japan that only increased in northern Japan through migration. In the east, the Kofun states of the Kanto had people midway between both Yayoi and Jomon populations. This shows that the settled population here, based on agriculture, most likely were a Jomon majority who accepted Yayoi settlers in their midst, and over time had absorbed them. This was also the case in the agriculturally based Tohoku Kofun states. In western Japan the Yayoi population became dominant because the Jomon had become exhausted both culturally and in numbers.
This trend in the Tohoku was accentuated most likely by a migration that took place from the north about the same time that the Kofun culture began to penetrate the Tohoku from the south (Kumagai 2004). This migration of Jomon peoples took place according to Kumagai between the third and fifth centuries AD, and its origin is most likely southern Hokkaido. In the midst of the gradual change in the population that was taking place in the Kanto and Tohoku, a fresh injection of Jomon peoples spread the Epi-Jomon culture into the Tohoku. In the complex picture that emerges then we have the gradual waning of the Final Jomon culture due to the growing influence of rice cultivation and the Kofun culture carried by Japanese speakers--clans headed by the great families (gozoku) in the fourth and fifth centuries, and then the waning of the power of these incipient states in the face of a fresh migration from the north of Jomon peoples, and the Epi-Jomon culture (also known as Latter Jomon) that spread back into the areas that previously saw to the retreat of the Jomon culture.
This latter culture was different from the earlier form, but its spread was due to the resurgence of the Jomon people. The Epi-Jomon culture in the Tohoku and Hokkaido is the culture that archaeologists have identified with what historians have called the Emishi, Ebisu and Ezo, and ancestral to the Satsumon culture. The Epi-Jomon saw to the spread of a type of pottery that was unique to southern Hokkaido and the Tohoku region. Hunting implements were also made by these people that indicated a diet consisting of Salmon, venison and berries. The Hokkaido region relied more on Salmon runs while the Tohoku region relied on hunting deer.
This culture differs from the earlier Final Jomon culture. The Final Jomon was by the material evidence quite rich and saw to the spread of lacquer ware as well as the creation of unusual clay figurines for religious purposes. The Final Jomon culture was centered on the area of present day Aomori, and is also known as "Kamegaoka" named for the region where many of these artifacts were first found. This culture dates to a time right before the advent of the Yayoi culture while the Epi-Jomon is thought to have occured during the Tohoku Yayoi. The Epi-Jomon culture is unusual in that instead of retreating north in the face of the Yayoi culture moves back towards the south during the Kofun period.
Kidder, Jr., J. Edward, "The earliest societies in Japan", in Brown, Delmer M., ed., The Cambridge History of Japan, volume1: Ancient Japan. Cambridge: Cambridge University Press, 1993.
Kumagai, Kimio. Emishi no Chi to Kodai Kokka. Tokyo: Yamakawa, 2004.