restricted access Chapter 6 Japan in Transition from Yayoi to Kofun
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59 Since Himiko was dead before AD 250 and Nara archaeologists are pushing the earliest mounded tombs back several decades, as will be discussed later, the first major evidence of a center of authority with the power to build large tumuli occurs in the first half of the third century. Social grading, a feature initiated by Yayoi immigrants in their preference for an agricultural lifestyle and the necessary supporting metal crafts to maintain it, had made this possible.These immigrants, many probably coming over as family groups that evolved into chiefdoms, produced not only the invigorating cultural mix but also the competitive spirit that fought for land and assets throughout much of the period. When one dominant group organized the loose aggregate of Yayoi chieftains into a federation, the Kofun period began. Population and Immigration Early population fluctuations in Japan reflected climate changes and the relative sources of food supplies.The Jòmon population was decreasing at an alarming rate by the end of the period.1 Looking back as to how this may have happened, we see that by the end of Early Jòmon the temperature had peaked a few degrees above today’s average and was going down. During this relatively temperate period (Middle Jòmon) much of the country’s population had discovered the rich forest products in central Honshu, chiefly the annual nut crops—walnuts, chestnuts, acorns, kaya, and even horse chestnuts (buckeyes). But with the temperature declining and probably short-term rapid vacillations and poor conditions, the deterioration disrupted normal life and forced large groups to disperse centrifugally, most moving toward the east coast and north into the Tòhoku. The temperature fell below today’s normal then rose slowly about the time rice growing took hold, to be then about what it is in the twentieth and twenty-first centuries. However, the Yayoi period itself was a slow cooling stage. The temperature of today has been reached by a steady rise since about the thirteenth or fourteenth century. By Latest Jòmon the population had further declined and was concentrated in forested upland and coastal plains. Large quantities of shell foods were consumed. There is no consensus as to why the population was decreasing so precipitously, but there is no evidence that rice was adopted to compensate for any deficiencies CHAPTER 6 Japan in Transition from Yayoi to Kofun in the diet or as a remedy for a declining population. A general view is that good conditions had produced an abnormally large population and it was adjusting itself to a less congenial environment and leveling off at a number more in keeping with the environment’s natural carrying capacity.2 The difficulties in computing population size from the number of sites are wellknown , but until a better method is found, the calculations made by Koyama will be the basis for the statistics that follow. Koyama based his demographic study on the forty-seven-volume National Site Maps published by the government in 1965,3 superimposing a grid system of 1,000 km2 on the map of Japan, thus arriving at 307 tracts for which all the sites within each were determined by period.Tracts with 0 to 8 sites were classified as thinly populated, 9 to 48 as well populated, and 49 or more densely populated.This is the legend for the comparative maps that illustrate the distributional difference between the Latest Jòmon and the Yayoi populations. Each region has its own geographical characteristics, so the quantity and quality of food resources, topographical features, and habitability of each were evaluated.The statistics listed in table 2 show the percentage of sites by region, from the population peak of Middle Jòmon through the successive declining stages, which may then be compared with data of the Yayoi period. Although the exact number of sites is considerably greater today, and arguments are always current as to whether some should be called components, the basic trends are apparent.4 Taking the regions all thought to be outside Himiko’s jurisdiction, that is to say, going north from the Tòkai and including the central more mountainous Chûbu, the west side Hokuriku, and the northernTòhoku, or about half of Honshu, we see that this enormous territory was home to roughly 86 percent of the population when rice was being brought in, leaving only some 14 percent living in the southwestern regions, where the first foreign components of the Yayoi culture made their appearance.5...