Okinoshima is a small island in the sea between Japan and Korea, and for five centuries the Japanese court sent offerings to it before ships crossed to the mainland.
Excavation has recovered tens of thousands of objects deposited between the fourth and ninth centuries, on and around rock formations on the island: bronze mirrors, iron weapons, gilt harness fittings, comma-shaped beads, and glassware whose origins lie as far away as Persia. The deposits were left in the open and were never disturbed, which makes the island an unusually complete record of what an early Japanese state ritual actually involved and of the goods that were moving along the route.
The island is the sacred body of a deity in the Munakata tradition, one of three sisters whose shrines are distributed between the island, a smaller island and the mainland coast, and the site has been treated as forbidden ground for a very long time. Access has been severely restricted, with entry historically closed to women and permitted to men only rarely and under purification, and the shrine has since closed the island to visitors entirely, including on the one day a year previously allowed. The rule that nothing may be removed from it has held throughout, which is why the deposits survived.
UNESCO inscribed the island and the related shrines in 2017 as a rare case of an ancient ritual site whose practice has continued without interruption.