Sone site is an underwater prehistoric site from the Incipient Jomon Period (c. 14,000?10,000 BC), which was the earliest discovered at the bottom of Suwa Lake in 1908. The discovery led to some debate in academic circles. Although a proper excavation has never been done, thousands of arrowheads and potsherds have been found at the bottom of the lake. Artifacts from this site are stored and exhibited at the Suwa City Museum. This site was designated a Suwa City Historic Site in 1972.