Stone tools of micro-blade sort (ca. 20,000 y. B.P.) at Koshikawa Site in Shari district, eastern Hokkaido, Japan

Obsidian stone tools were discovered at a tephra outcrop in Shari district, eastern Hokkaido, Japan. This site was named Koshikawa Site. The main stone tools obtained from the outcrop were flakes. Some of them are identified morphologically as microblades. 14C dating of charcoals buried with the stone tools in burned soil, gave an age of 23, 430±820750y. B. P. (NU-056). The age indicates that Koshikawa Site is one of the oldest archaeological sites in Hokkaido, and that the Micro-blade Culture presumably developed earlier in Hokkaido than has been thought