New underwater surveys in the Tsushima Strait have revealed the existence of the 'Cinnabar and Jadeite' Seaway, a vibrant maritime trade network that connected the Jomon-Yayoi transition period in Japan with the Mumun pottery period in Korea. Divers recovered specialized stone weights and ceramic shards containing traces of mercury-based cinnabar, which was used as a prestigious pigment in both cultures.
The findings prove that sophisticated maritime interaction was occurring across the strait much earlier than historical records suggested. The exchange of jadeite ornaments and ritual minerals helped forge early social hierarchies and shared religious practices across the sea. This research is part of a larger project to map the submerged prehistoric landscapes of East Asia that were lost to rising sea levels after the last ice age.