Abstract
Findings from a survey of architectural members and iron tools excavated from the ruins of the Yayoi and Kofun periods are summarized as follows :
(1) Among major architectural wooden materials in Japan，the most often used in the Yayoi and Kofun periods were Japanese cedars，Japanese cypresses，and chestnut trees，
(2) Appropriate types of wood were selected for the various elements of wooden buildings，based on the particular characteristics of each species chosen.
(3) An element of technology that seems to have been handed down from the Jomon period to the Yayoi and Kofun periods seems to be the processing methods for the joints of architectural members
(4) The categorization of tools in the Jomon period is thought to be handed down to the categorization of tools used in the various stages of logging， lumbering， and the processing of architectural members during the Yayoi and Kofun periods.
(5) As far as iron axes and adzes are concerned，it appears that iron axe blades were classified into axes for felling and adzes in the Yayoi period and were classified into axes for felling，axes for rough hewing，and adzes in the Kofun period according to respective functions.
(6) 1ron chisels in the Yayoi and Kofun periods are thought to have been classified into large chisels using axe blades and chisels for rough processing or finishing according to respective functions.
(7) The categorization of major architectural tools in the Yayoi and Kofun periods seems to consist of iron axes，adzes，and chisels.
