The site of a major archeological discovery, Iwajuku (岩宿) provided evidence of habitation of Japan by humans before the 10th millennium BC. To date, these are the oldest records of human dwellings from Japan's past. Excavations in 1949 following the discovery of the site by Aizawa Tadahiro confirmed the existence of two cultural strata, one of which contained small tools such as Projectile points and blades made of obsidian and agate. Iwajuku is in the town of Kasakake, Midori, Gunma Prefecture (Nitta District)
- Keiji Imamura. Prehistoric Japan: new perspectives on insular East Asia p. 19.