During the Jomon period asphalt was used as a binder to fix a harpoon or a fishspear in its shaft, to tie a sring with a spoon-shaped lithic knife or a stone weight, and to mendbroken pottery (Figure 1).
The use of asphalt began about 3, 300 B. C., saw its climax in the latter part of the Late Jomonand Final Jomon periods (about 1, 500-300 B. C.), and was suddenly abandoned in the Yayoi period.During the Jomon period, asphalt was collected only in the oil-fields along the Japan Sea side areasof the Tohoku district where it came out to the surface. Tukinoki and Komagata in Akitaprefecture and Yunodai in Yamagata prefecture are well-known locations of the surface asphalt. InNiigata prefecture oil-layers lie near the surface and, therefore, crude oil came out to accumulate inponds located on foothills and is found half-soild along the pond shore. During the Jomon period, the asphalt collected in the oil-producing areas was distributed in the whole Tohoku district alongseveral trading routes (Figure 2).
Dr. Masa-aki Ogasawara from Hokkaido University started a chemical compositional analysisof asphalt. As the chemical analysis enables to source ancient asphalt, exchange networks of Jomonpeople and relationships between areas will be documented more clearly.