著者

藤尾 慎一郎

出版者

国立歴史民俗博物館

雑誌

国立歴史民俗博物館研究報告 (ISSN:02867400)

巻号頁・発行日

vol.149, pp.135-161, 2009-03

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弥生集落論は,同じ土器型式に属する弥生土器が床面直上から出土する住居を,同時併存,すなわち同時に存在したとみなしてきた。土器一型式の存続幅が30~50年ぐらいで,一世代と同じ時間幅をもつと考えられてきたこともあり,とくにその傾向が強かった。縄文集落論では,縄文土器の大別型式一型式の存続幅が百年程度だったので,1970年代から,同時併存の遺構の認定法をめぐって盛んに議論がおこなわれてきた。現在では,小林謙一の較正年代にもとづいた一段階20年以内での同時併存を認定するまで研究が進んでいる。しかし弥生集落論においても,較正年代を用いれば,板付Ⅱa式や板付Ⅱb式のように,存続幅が百年以上にわたる可能性のある型式の存在がわかってきたため,縄文集落論に遅れること40年にして,同時併存の認定に関する議論をおこなわなければならない段階に至ったといえよう。検討の結果,同時併存住居の認定は,存続幅が短い前期末や中期初頭においてはかろうじて可能なことがわかった。一方,存続幅が長く現状では同時併存住居の認定が難しい板付Ⅱa式や板付Ⅱb式も,もともと存在した住居の累積軒数が土器型式ごとに表されたものと考えれば,存続幅が短い板付Ⅱc式段階の累積棟数と比較するなどして,各段階の特徴を相対的に評価できることがわかった。土器一型式の存続幅を考慮した集落論は,同時併存住居5棟を一単位とする集団構造論の前提を再考しなければならなくなった一方で,これまでの弥生研究では解決の糸口が得られなかった時間的側面を前面に押し出した,弾力的な人口増加率などの研究テーマに新たな可能性の扉を開き始めたといえよう。According to Yayoi settlement theory, Yayoi pottery belonging to the same pottery type excavated directly from the floor of a pit dwelling is thought to have existed simultaneously with the pit dwelling. Each Yayoi pottery type lasted for about 30 to 50 years, and it was firmly believed that they lasted for the same length of time as a single generation.Since according to Jomon settlement theory the broad types of Jomon pottery lasted for around 100 years, from the 1970s there has been much debate surrounding methods of identifying relics that co-existed at the same time. Research has progressed to the extent that today coexistence is identified within a single 20-year phase based on calibrated dates by Ken'ichi Kobayashi.However, if we use calibrated dates we find that there were pottery types like Itazuke IIa and Itazuke IIb that continued for more than a 100 years. Consequently, today, some 40 years behind Jomon settlement theory, Yayoi settlement theory has reached the stage of having to debate the identification of simultaneously co-existing pit dwelling.The results of this study show that it is just possible to identify pit dwelling that co-existed simultaneously at the end of Early Yayoi and the beginning of Middle Yayoi when pottery types lasted for a short time. But even for Itazuke IIa and Itazuke IIb types, for which it is currently difficult to identify simultaneously coexisting pit dwelling due to their long duration, assuming that the number of cumulative dwellings that existed represented each pottery type, the author found that it is possible to make a comparative evaluation of the features of each stage by comparing the number of cumulative pit dwelling to the cumulative number for the Itazuke IIc type stage, which lasted for a short time.Settlement theory that takes into account the duration of each pottery type necessitates a review of the premise of the theory of group structure that considers that five simultaneously coexisting pit dwelling form a single unit. Nonetheless, it brings to the fore the temporal aspect of Yayoi research, for which clues have remained elusive until now, and opens the door to new possibilities for research topics, such as variable rates of population increase.