The site is located northwest of slope of Mount Kirigamine at an altitude of 1500 meters, in a 35,000 square meter forested area. Obsidian, or volcanic glass was frequently used for tools and weapons in the Japanese Paleolithic period as it could be fractured to produce sharp blades or arrowheads, and frequently occurs in volcanic formation around Japan. Excavation surveys found that obsidian was extracted from here from the early Jōmon period (about 5,700 years ago) and late Jōmon period (2000-1000 BCE). Chemical analysis also indicated that obsidian from this site was supplied to settlements distributed across an extremely wide range from Tōhoku to the Tōkai region, indicating long distance trade. The site was discovered in 1920, and was excavated from 1959-1961, and again in 1997.