We have here designated the vanquishers of the Ainu, for the sake of convenience, simply by the name of Japanese. Were they the Japanese in the same sense as the word is understood by us now? Were the vanquishers a homogeneous people, or a heterogeneous one? If the Japanese were heterogeneous, who were the first comers among them? Who were the most prominent? All these are questions very hard to answer clearly. It is sometimes argued that we had only one stock of people in Japan besides the Ainu, and that that stock is the homogeneous Japanese. This view is not avowed openly by any scholar worthy of mention, for it is an undeniable fact that in the historical ages groups of immigrants, intentional as well as unintentional, happened to drift into Japan now and then, not only from Korea and China, but from the southern islands also, though not in great numbers, and the occurrence of migrations similar to those in historic ages cannot be absolutely denied to prehistoric times. Besides, any one who pays even but cursory attention to the physical features of the Japanese can easily discern that, besides those who might be regarded as of a genuine Korean or Chinese type, there are many among them who have a physiognomy quite different from either the Korean or the Chinese, though one might be at a loss to tell exactly whether the tincture of the Malayan, Polynesian, or Melanesian blood is predominant. In face of such diversity, too clear to be neglected, none would be bold enough to assert that the Japanese has been a homogeneous race from the beginning. Strangely enough, however, this evidently untenable conception still lies at the bottom of many historical hypotheses, which will be set right in the future.
If it is most probable that the Japanese is a heterogeneous race, then what are the elements which constitute it? The results of the investigation of many scholars tend to place the home of the bulk of the forefathers of the so-called Japanese in the northeast of the Asiatic continent. Perhaps, from the purely philological point of view, this assumption may be more approximate to the truth than any other. The singular position of the Japanese language in the linguistic system of the world leaves little room for the hypothesis that the bulk of the race came from the south, though it is not at all easy to derive it from the north. In our language we have very few words in common with those now prevailing in the islands which stud the sea to the south of Japan, or in the southern part of the Asiatic continent. On the other hand, the language the most akin to ours is the Korean, though the gap between it and the Japanese language is far wider than that between the Korean and the other continental languages, such as the Mongolian and the Manchurian. If we take, therefore, linguistic similarity as the sole test of the existence of racial affinity, as many scholars are prone implicitly to do, then the bulk of the Japanese must belong to a stock which stood at some time very near to the forefathers of the Koreans, though not descended from the Koreans themselves. In other words, the Japanese race may be supposed to have had as its integral part a stock of people, who might have lived side by side with the ancestors of the Koreans for a longer time than with other kindred tribes. And if that be really so, the Japanese must have separated from the Koreans long before the end of the prehistoric ages; otherwise we cannot account for so wide a divergence of the two languages as we see at present.
It is a very dangerous feat, of course, to determine any ethnological question solely from a philological standpoint. For the sake of argument, however, let us assume for a while the hypothesis that the main element in the Japanese race came over from the northern Asiatic continent on the opposite shore of the Sea of Japan, by way, perhaps, of the peninsula of Korea and the island of Tsushima, or across the Sea of Japan. The ethnologists who adopt this view assume that the Chinese must be excluded from the above body of immigrants, the Chinese who were doubtlessly a far more advanced people even in those ages than the other neighbouring races, and were destined to become the most influential benefactors of Japanese civilisation. If regarded from the linguistic point of view only, it may be not at all unnatural thus to exclude the Chinese blood from the veins of our forefathers. In order to do so, however, it would be necessary at the same time to presuppose that the Chinese never came into close contact with the forefathers of the Japanese while the latter were sojourning on the Asiatic continent. It is not, of course, impossible to suppose that the ancestors of the greater part of the Japanese came over into this country without touching China anywhere, because they might have come from eastern Siberia, northern Manchuria, or some other quarter, narrowly avoiding coming into contact with the Chinese, though, actually, it is not a very easy matter to imagine such a case.
Let us, then, drop all idea of the Chinese, and suppose that that race can be put aside in our consideration of the prehistoric Japanese without glaring unnaturalness. Still the question remains unsettled, whether the bulk of our ancestors from the continent contained within it the ruling class, who gave a unity to the heterogeneous population of this Island Empire. One would say that a certain stock among many, who had their abode in northeastern Asia, might have become predominant over the kindred people of various stocks settled previously in Japan. And the cause of the predominance may be supposed to have been a decided advance in civilisation on the part of the chosen stock. That is to say, the tribe in question might have been already in the iron age with respect to its civilisation, while other tribes were still lingering in the neolithic age. But in order to sustain this supposition, it is necessary to premise another assumption that the predominant stock was comparatively late in coming over to Japan, and that it had already attained the civilisation of the iron age before its immigration into Japan while the other inferior tribes remained at a standstill in their civilisation after settling in our country. Such an assertion, however, cannot be deemed probable without admitting that there was a considerable interruption of communication between Japan and the Asiatic continent before the immigration of the predominant stock. Otherwise it would be very difficult to entertain the idea that the civilisation of northeastern Asia could remain alien to the inhabitants of Japan for so long a time as to cause a wide difference in language, manners and customs, and so on, between the peoples on the two opposite shores of the Sea of Japan.
Besides, to suppose that the forefathers of the greater portion of the Japanese people were immigrants from northeastern Asia, is, by itself, nothing but a hypothesis, supported by a few remains only, which can be interpreted in more than one way. To go one step farther, and assume that the ruling class of the Japanese too came over from the continental shore of the Sea of Japan is another matter, too uncertain to be readily accepted. Whatever degree of probability there may be in these assertions, there are certain items in our history to the natural interpretation of which any solution of all the ethnological problems must conform; and among those items the following are the most important.
The first to be considered is the style of the Japanese building, especially the style of the Shinto shrines and of the dancing halls frequently attached to them. The architectural style of the ordinary Japanese house has undergone many successive changes during the long course of its history, so that its primitive form is now, to a great extent, lost. For instance, the tatami, a thick mat, which covers the floor of a Japanese room and is now one of the most remarkable characteristics of Japanese household fittings, is a comparatively modern invention, only planks having been originally used as the material for flooring. Buddhistic influences too can be traced distinctly in a certain turn of construction copied from China, first in building Buddhistic temples and then widely adopted in building ordinary dwelling-houses. In some essential points, however, there are several traits which cannot be ascribed either to an imitation of any continental style or to the result of a gradual adaptation to the climate. Any one can easily see that the ordinary Japanese house may be good for summer and for southern Japan, but not for winter, especially for the rigid winter of northern Japan. How did such a style come into being? If it had been brought from the northeast of the Asiatic continent by the ancient immigrants