Abstract: 1. Earliest Evidence of Human Occupation in the Japanese Archipelago
The earliest evidence o f human occupation in the Japanese archipelago dates back to 600 kya ( 600, 000 years ago ) , as evidenced at the Kamitakamori site in Miyagi prefecture o f the Tohoku district, northeaster n Ja pan ( Fig. 1. 2) . Such recent progress in the Paleolithic studies a re realized by cooperation between archaeologists and g eologists.
2. Tephrochronology and the Paleolithic Chronology
In Japan, both the relative and absolute dates o f Paleolithic sites are beyond doubt owing to tephrochronology ( Fig . 2) . The absolute dates of the volcanic ash may be obtained by thermoluminescence, electron spinning resonance, fission track, and paleo-magnetic dating methods. Moreover, the result of investigations into tephras at different sites ca n be tied to gether if the tephras were results of the same eruption of a volcano. Key tephras include the Aira Tanzaw a pumice ( 23 kya) , Aso-4 ( 70kya) , Ontake-1 ( 80ky a) , Sanbe Kitsugi ( 80-90 kya ) a nd Toya ( 90-100 kya ). Accordingly , it is possible to build a spatially broad framework of chronology into which Paleolithic sites of different regions may be placed. Such a firm chronological basis is extraodinarily unusual.
3. Division of the Paleolithic Period in Japan
Until five years ago , the Paleolithic period in Japan w ere divided into two stag es, namely Early ( until 30 kya) and Late ( 30 to 12 kya ). But the Japanese archaeologists have recently accumulated enough data to separate the Middle Paleolithic stag e ( 130 to 30kya) from the conventional Early stage.
4. Early Paleolithic Period (until 130 kya) in the Japanese Archipelago
Lithic artifacts of the Kamita kamo ri site were discovered in astratum lower than the stratum of 500kya ( Tm-1) . It is important that the Kamitakamori assemblage consisted o f small flake tools made from chalcedony and jasper, as w ell as samll adzes with a bifacial flaking and cleaver-like too ls made from shale ( Fig. 3, 4) . At the Kamitakamo ri site, small adzes and cleaver-like tools w ere additionally discovered in tephras dated between 300 and 500 kya. Some archaeologists suspect that the presence of such tools as small adzes and cleaver-like ones were a result of influence of heavy-duty too ls from the Acheulian culture. Anothernoteworthy aspect of the Kamitakamori assemblage is the strong preference for chalcedony and jasper in raw materials of other small tools, despite shale also being suit- able. This selection of raw materials was not simply a matter o f function, but also reflects the influence of other cultural factors.
The Takamori site which is near the Kamitakamori site was dated back to possibly 470 kya by paleomagnetic dating. The lithic assemblage at the Takamori site mainly consisted of light-duty tools including pro to-knife-shaped too ls, small bifaces, drills, and scrapers, mo st o f which w ere made o f chalcedony , jasper and agate ( Fig. 3, 4). Small adzes w ere absent in the Takamori assemblage. This suggests a functional differentiation of tool types rather than a chrono logical difference. The assemblage might have included heavy- duty tools because o f the similarity in assemblages to the Nakamine-C ( stratum Ⅶ ) and Babadan-A ( stratum 20) sites w here chopping-too ls and picks w ere discovered ( Fig. 4) .
5. Middle Paleolithic Period ( 130-30 kya) in the Japanese Archipelago
Middle Paleolithic sites hav e mainly been investigated in Miyagi, Fukushima, Yamagata and Gumma prefectures of the Tohoku and Kanto districts where Pleistocene tephrasa re accumulated in good stratigraphic contexts. Such sites include Takenomori (dated to 130- 110kya ) , Babadan, Yamadauenodai and Zazaragi ( Fig. 5a. 5b) . Some too l types continued to be present since the Early Paleolithic period, such as pro to-knife-shaped tools, small bi-faces, small adzes which suggests a continuous development of technological traditions from the Early Paleolithic period. At the same time, some importa nt changes tookplace. First, the dominant raw material from which tools were made became shale in lieu of chalcedony, jasper and agate. New lithic technology and new types of tools appeared, including slanted points, flaked from discoidal cores, and axes ( o r adzes). Current archaeological evidence show s that these aspects of the Middle Paleolithic assemblage w ere common at least in eastern Japan. New lithic technology of the slanted flakes flaked from discoidal cores were generally present in Japan from Iwate in the northeast to Fukuoka in Kyushu ( south- w est) , with the exception o f Hokkaido where no Middle Paleolithic sites have been discovered.
6. Middle-Late Paleolithic Transition in the Japanese Archipelago
Transition from the Middle Paleolithic to Late Paleolithic Japan took place between 35-30 kya. The Late Paleolithic period in the Japanese archipelago is characterized by an in- crease in the size and quantities of elongate flakes as w ell as the development of the blade technique and knife-shaped tools. Some Japanese archaeologists maintain that the transition from the Middle Paleolithic to Late Paleolithic Japan was a matter of internal development. This hypo thesis is backed by a continuous development of technological traditions from the Early to Late Paleolithic stag es that a re evident in two classes of lithic artifacts ( Fig . 7, 2) . Th e first class is of tools. Knife-shaped tools and flake-trapeze-shaped too ls developed from proto-knife-shaped tools in the Early Paleolithic period. The second class is of elongate flakes, which w ere flaked from a discoidal core, characteristic of the Middle Paleolithic period ( Fig. 5b) . Knife-shaped too ls probably used as spears promoted an increase in the length of knife-shape tools. According ly, elongate flakes eventually gave a birth to blade tools.
7. Possible Relations with the Nothern and Eastern Asian Continent during the Early and Middle Paleolithic Period
7. 1 First peopling of the Japanese Archipelago How people arrived in the Japanese archipelago was constrained by people 's adaptation to the environment a t the time of migration. No people generally reside in regions north o f 40 degrees latitude during glaciation. It was impossible to migrate to the archipelago from the north via Hokkaido, and the remaining possibility would be from the Asia n continent via the Korea n Peninsula and Kyushu. If the data o f the Kamitakamori and Takamori sites are indeed 500-600 kya, the possible glacial episode which allow ed for mi- g ratio n to the archipelago would be the Gǜ nz or Mindel glaciation.
7. 2 Functional Differentiation of tools Lithic assemblages o f the Early and Middle Paleolithic period in the Japanese archipelago suggest a functional differentiation between light-duty tools and heavy-duty tools. Acordingly , in some cases such as the Takamori site people used only light-duty too ls, in other cases such as the Nakamine-C ( stratumⅦ ) and Babadan-A ( stratum 20) sites people used both kinds o f tools.
7. 3 Importance of Bifacial Flaking in the Early Paleolithic Period in East Asia A discovery o f small adzes made from shale at the Kamitakamo ti site suggests that a bifacial flaking technique possessed by people in Early Paleolithic Japan already reach ed a level of considerable sophistication. In other words, the Early Paleolithic people had some potential to make typical handaxes. If this bifacial flaking a t this level was introduced by people who migrated from the Asian continent to the Japanese archipelago before 600 kya, it is possible to discover typical handax es in China and its surrounding s in the future, to o. That a technical level o f fabricating some handaxes in China is no t necessarily high, implies that the technology was constrained by the quality o f lithic raw materials. The presence of bifacial flaking in the Early Paleolithic period in East Asia is relevant to research into human dispersal to East Asia.
7. 4 Lithic Industry Commonly Distributed in the Northern Pa rt of Ea st Asia during the Middle Paleolithic and Middle-Late Paleolithic Transition Lithic industry consisting of discoidal cores, slanted flakes flaking from discoidal cores and slanted points, drills and other tools made from slanted flakes w as widely distributed in the North China such as Loc. 54∶ 100 in Ding cunsites, Loc. 15 in Zhoukoudian sites and Loufangzi site, besides the Japanese archipelago ( Fig. 6) . This phenomenon suggests possible diffusion between the North China and the Japanese archipelago. The earliest evidence of this industry in Japan is the Lower Stratum Takenomori dated to 130-110kya ( Fig. 5b) , corresponding to the beginning of the Riss-Wǜrm inter-glaciation. But it w as impossible to migrate from the Asian continent and the Korean Peninsula via the Korean Strait to the archipelago at the time o f global warming. According ly , w e must pro pose an alternative hypothesis that an introduction o f new industry into the archipelago is dated back to the last stag e of the Riss glaciation, 150 kya.
This industry including discoidal cores had continued to the Middle-Late Paleolithic transition 40-30 kya, as evidenced by discoveries at the Tashuihe and Shiyu sites ( Fig. 7). Production o f elongate flakes or proto-blades started from this transition. Although the internal development hypothesis in Japan is accepted by some archaeologists, it does no t ex plain many phenomena, such as the preference of elongate flakes in the Middle-Late Paleolithic transition in Japan, the process of the perfection of the blade technique, and the appearance of microblade technique common to Northern Eurasia. For these reasons, a comparative approach to Paleolithic material cultures between North and East Asia and Japan in still essential.
7. 5 Diffusion of the Mousterian Culture to the Southwestern Part of the North Asia Although it has become clear that the Mousterian assemblages characterized by the Levallois technique were distributed to eastern Mongolia beyond the Altai mountains, the Levallois technique did not diffuse to the south and east o f the Gobi desert ( Fig . 7). Moreover, the date o f the Mousterian assemblages in the Altai mountains and eastern Mongolia is 80 to 70 kya, which is later than the date ( 150-130 kya) o f the appearance o f slanted points in China and Japan similar to a Mousterian point. In other words, the Early-Middle Paleolithic transition in China and Japan too k place earlier than the diffusion of the Mousteria n culture to eastern-central Asia, and Middle Paleolithic East Asia was not under the direct influence of the Mousterian culture.
The presence of the Mousterian assemblages in eastern Monglia suggests migration of people from Central Asia. Who were these people carrying the ousterian assemblages, modern Homo sapiens or archaic Homo sapients? Did they mix blood with people living in the north part of East Asia? These are very important problems o f physical anthropology and Paleolithic archaeology.

Key words: Teph rochronology, Heavy-duty tools, Light-duty tools, Japanese archipelago, Early and Middle Paleolithic period