As the knowledge of Chinese culture began to pile upon in Japan there arose the increasing problem of how to integrate the new elements into Japanese life. The earlier solutions were to adapt it wholesale, but slowly Japanese became sufficiently skillful in the manipulation of Chinese culture traits to be able to discriminate between the merely new and the really useful aspects of Chinese traits. Not only was this process operative among the political leaders of Japan who dropped out features they did not like, but it gradually became applied throughout the whole range of Japanese life. In the mild climate of southern Japan the domestic architecture of North China was hardly necessary, and its strictly utilitarian features were too subdued to appeal to the Japanese. Slowly there evolved several distinctive Japanese housetypes, variably using movable panel walls, designed to let in light and sun, clean floors and mats, and a minimum of furniture reminiscent of southeastern Asia. Taken from Chinese patterns, Japanese housing still resembles its origins in many respects, but it is distinctively different.
Japanese agriculture basically resembles that of China in many respects, but it has developed its own distinctive methods, tools, and customs. The early arts of Japan closely resemble those of China, but gradually there have evolved subtle distinctions that often are hard for the occidental to recognize but that the educated Chinese and Japanese know well. This holds true in painting, sculpture, literature, drama, and the whole range of decorative and utilitarian arts. It holds true for many of the social customs, such as the ceremonial greeting, for dietary habits, such as the use of tea as a national drink, for the patterns of clothing, and many other elements of culture. In all these things the Japanese have slowly modified the basic elements into something peculiarly Japanese.
The process of converting Chinese cultural examples into Japanese customs and material developments was not done rapidly. The earliest elements in this adaptation of Chinese culture came early during the period when the Japanese were still consciously studying Chinese affairs. The most distinctive transformations, of course, came in the centuries after the Japanese had stopped observing China, and were independently living their own lives. The culture historian is apt to classify the centuries between about A.D. 900 and A.D. 1400 as the most important era of activity in the field of cultural transformation. The political historian is apt to divide the time span between about A.D. 800 and A.D. 1550 into two eras in which he first distinguishes the attempt to install a system of political nationalism and, second, the development of feudalism in Japan after about A.D. 1000.
In the sixth century A.D. the Japanese already were pushing northward beyond the Inland Sea and into the edges of the hill country of central Japan. As their culture developed more and more, and their population increased, the contrasts between the southern peoples and the aboriginal population of the north and the hill country heightened. There began a process of expansion northward out of the hearth that can be likened to the expansion of the seaboard American colonies westward across the United States. It was a slower process, and it involved different kinds of issues, but there are similarities. The Japanese had to fight their way northward against a stubborn resistance on the part of the hunting and gathering aboriginals who did not want to see their hunting ranges turned into farmlands. There developed a professional soldiery on the frontier who resembled the American "Indian fighter," settlers often found their advance locations raided, and forts and a frontier force of farmer-soldiery were employed. Some Japanese left the settled areas for various reasons and took up residence among the Ainu, often inciting them to resistance. By the end of the eighth century the lowlands well north of modern Tokyo had been cleared of Ainu, and considerable settlement by southerners had taken place. During the eighth and ninth centuries the Japanese pushed steadily northward, slowly learning the military techniques required to conquer the Ainu. By the end of the ninth century the strength of the Ainu had been broken, though groups remained in the uplands to bother the Japanese for another century or more. Some intermarriage steadily introduced Ainu blood and physical types into the Japanese people.
The Ainu had been a hunting and gathering people who lived along the shores of the islands and used the lowland interior regions that provided fish, game, and some plant resources. In the north country they found little in the mountain country of value, and increasingly found their range of support reduced as the southerners conquered the coasts and lowlands. Ainu had also inhabited the shores of Hokkaido for a long period, and some of them retreated to Hokkaido when dispossessed on Honshu. In Hokkaido, however, the upland country was largely barren of resources useful to hunters and gatherers, and the Ainu stuck to the coastal fringes and some of the more open lowland areas. In taking over Ainu territory the southerners found little developed land upon which to base their own occupation. They faced a forested environment with a cooler climate having few directly useful land resources to begin with. Their occupation of the north country, therefore, was a slow matter of clearing forests, developing fields on rough surfaces, changing their crops, and finding short-season varieties of crop plants that would mature in the cooler, shorter growing seasons.
Throughout northern Honshu, therefore, settlement and resource development was slow. Many Japanese settlements came to depend more upon fishing than upon agriculture. In many respects the southern people moving northward did not basically alter their southern patterns of culture. Housetypes, clothing, food patterns, customs, and habits remained much the same. The northern, colder parts of Honshu were slow to fill up with settlers, many of whom found this northern country unattractive in comparison to the milder portions of southern Japan. It was almost A.D. 1400 before most of the easily settled land of northern Honshu was occupied.