(1) From mainland China to Hokkaido

Kazuchika Komai became a research associate in the Faculty of Letters at Tokyo Imperial University in 1927 and participated in the Far Eastern Archaeological Society, an academic society established that year, mainly by professors at Kyoto Imperial University and Tokyo Imperial University, in order to promote archaeological investigations in East Asia. As oriental archaeologists, Komai and Yoshito Harada, the first professor of the course of Archaeology at Tokyo Imperial University and an active participant in the Far Eastern Archaeological Society, promoted archaeological investigations in China and Korea.

After World War Ⅱ, the Far Eastern Archaeological Society carried out an excavation of the Toro Site at Shizuoka City and the Moyoro Shell Mound at Abashiri City in 1947. Komai became an associate professor at the Department of Archaeology of the Faculty of Letters, established in the preceding year, and he played an active role in the excavation of these archaeological sites.

It is understood that, after World War Ⅱ, Seiichi Mizuno at Kyoto University and Komai decided that Kyoto University would focus on Iki and Tsushima in Kyusyu and that the University of Tokyo would focus on Hokkaido (Sugimura 1977). This was because they wanted to clarify the relationship between continental Eurasia and Japan in the western and eastern regions, the contact point between the Asian continent and the islands of Japan (Onuki 2002). After the investigation in the Moyoro Shell Mound, Komai decided on Hokkaido as a new site for his archaeological studies. Thereafter, he promoted research into clarifying the history of the Ainu through archaeological methods and materials, which he called “Ainu Archaeology.”

(2) Investigation of stone circles and shell mounds

Alongside the Moyoro Shell Mound, Komai focused on the stone circles of the Jomon period ⁽¹⁾ and on the shell mounds from the Jomon and Epi-Jomon periods. Komai pointed out that the potteries and bronze artifacts of the Okhotsk culture have features of the Asian continent. He also examined the stone circles in Hokkaido because of their similarity to the megalithic monuments that are widely distributed in Europe and Asia, especially Siberia. In addition, before the war, Komai had investigated the stone circle in the south of Hyrule, located in the northwest part of Manchuria (the Inner Mongolia Autonomous Region, today part of China), and he had confirmed that it was a kind of tomb, so he wanted to clarify the characteristics of the stone circles in Hokkaido. He therefore began to excavate the Jichin’yama Stone Circle in Yoichi Town in 1949 and undertook the excavations of the stone circles in Hokkaido until 1956.

Komai did not clearly explain the motivation for the investigation of shell mounds, but according to Shizuo Onuki (Onuki 2002), these investigations were carried out in order to find human bones and study them anthropologically. Many human bones were excavated in the Moyoro Shell Mound. Komai heard the results of the morphological study and believed that the Okhotsk people assimilated into the Ainu after migrating from outside Hokkaido. It seems that this study gave Komai the motivation to carry out the study of shell mounds and human bones. After that, Komai began his investigations in Hokkaido in order to answer three questions: “When did the ancestors of Ainu start living in Hokkaido, and where did they come from and where did they settle down?” (Komai 1973:138).

It was 1949 when Komai excavated the Higashi Kushiro Shell Mound from the Jomon period at Kushiro City, next to the excavation of the Moyoro Shell Mound (Komai 1952, Kono and Sawa 1962). However, there are no records of the chronological table (Komai [Fujie ed.] 1977) for this excavation, and no detailed investigation reports have been published. Komai also observed some chashi sites around the Higashi Kushiro Shell Mound and took photographs at the time.

Komai also carried out the excavation of the Ojironai Shell Mound from the Epi-Jomon period at Mori Town. This excavation was started in 1951 and continued until 1953, with a supplementary investigation being conducted in 1958.

Furthermore, in addition to the excavation of the stone circles and shell mounds, in 1951 Komai also carried out a general survey at Utoro, Rausu, and its surroundings while based in Abashiri (Komai 1964: 99). This general survey later led to an excavation at the Shiretoko Peninsula.

(3) Encounter of Komai and Tokoro Town

The next turning point in Komai's investigation in Hokkaido was the encounter with Tokoro Town (Kitami City today). It was Shiro Hattori and Nobutake Onishi who led the encounter. Hattori was a professor at the Faculty of Letters of the University of Tokyo who visited Tokoro Town to conduct research into the Sakhalin Ainu language. Onishi was a local person who argued for the importance of the archaeological sites in Tokoro Town.

Hattori started a linguistic survey of the Sakhalin Ainu language in Tokoro Town in 1955 and encountered Onishi there. When Hattori visited Tokoro Town again the following year, Onishi asked him to invite archaeologists from the University of Tokyo. Komai heard this from Hattori, visited Tokoro Town, viewed the archaeological sites in Tokoro with Onishi in the fall of that year, and decided to carry out an excavation. Komai wrote that it was because he had “come up with the idea of investigating the archaeological sites, such as the shell mounds, tombs, pit houses, and chashi on the Okhotsk Sea coast and the Shiretoko Peninsula” and that “most of the archaeological sites were near Tokoro Town, which I visited in the fall of 1956, and I found the big shell mound here.”

The excavation started in Tokoro Town in 1957 and has continued as a research project of the Department of Archaeology at the University of Tokyo to the present day. In parallel with the excavation at Tokoro Town, excavations were carried out at Shari and Rausu towns on the Shiretoko Peninsula for three years, from 1958 to 1960. Komai led these excavations until 1959 but has not participated in the excavation since then.

As the research results in Tokoro accumulated, Komai hoped to build an “Ainu Research Center” as a site for research and study (Komai 1960 [written again in Komai 1977:190]), retiring from the University of Tokyo in 1965. It was in December of that year that the “Tokoro Town Museum” was established by the town, subsequently becoming the first building of the Tokoro Research Laboratory. Two years later, in 1967, the Faculty of Letters dispatched a research associate from the Department of Archaeology, and the facility known as the “Tokoro Field Laboratory” was established. This was the beginning of the Tokoro Research Laboratory that continues to this day.

(4) Chronological table of investigation in Hokkaido

With regard to Komai’s work mentioned above, the archaeological investigations carried out only in Hokkaido are as follows.