[1] The site was discovered when a Shinto shrine was being renovated near the fishing port of Himi in 1918.

Within a large natural cave created by wave action, a number of bones and Jōmon pottery fragments were discovered and during a subsequent excavation by the Tokyo Imperial University, stone tools, earthenware, the bones of approximately 20 people were found.

The current floor is about four meters higher than the present sea level.

The Ōzakai site was the first cave site in Japan and stratigraphic examination indicated that it had been occupied from the middle Jōmon period through the Kamakura period: The discovery of the Yayoi period human remains drew attention to the Yayoi custom of ritual tooth extraction and secondary burial (the skulls had red paint).

[2] Media related to Ozakai Cave Dwelling Site at Wikimedia Commons