Bodies of Water

Sea of Japan

Also Known As East Sea The Korean name for the same water; the naming is disputed. · Japan Sea The bare form of the name. The atlas files this entry under a longer, shorter or differently punctuated form.

Seas

Citation Formats

General Reference

Divinity Atlas. "Sea of Japan." Accessed August 30, 2026. https://dev-divinity.interactiveatlas.org/bodies-of-water/sea-of-japan.

APA Style

Divinity Atlas. (n.d.). Sea of Japan. Retrieved August 30, 2026, from https://dev-divinity.interactiveatlas.org/bodies-of-water/sea-of-japan

BibTeX

@misc{divinityatlas-sea-of-japan,
  author = {Divinity Atlas},
  title = {Sea of Japan},
  year = {2026},
  url = {https://dev-divinity.interactiveatlas.org/bodies-of-water/sea-of-japan},
  note = {Accessed August 30, 2026}
}

The Sea of Japan lies between the Japanese archipelago and the Asian mainland, and it is the water across which Buddhism, Chinese writing and continental ritual reached Japan from Korea in the sixth century and after. The island of Okinoshima in its southern approaches received ritual deposits of mirrors, beads and gilt objects from the fourth to the ninth century, offered by the Yamato court for safe passage, and the Munakata shrines still hold it as sacred ground. Korea calls the same water the East Sea, and the naming is a live dispute that the atlas records rather than settles.

Facts

Significance

Sacred Role

The crossing that had to be made safe. From the fourth century to the ninth the Yamato court left mirrors, beads, gilt harness fittings and imported glass on Okinoshima for safe passage, some eighty thousand objects in all; the island belongs to the Munakata shrines and was inscribed by UNESCO in 2017. 1

Disputed

Region

Bordered by Japan, South Korea, North Korea and Russia. The name is disputed: Korea calls the same water the East Sea and has pressed for dual naming at the International Hydrographic Organization, which in 2020 moved instead towards numeric identifiers for sea areas rather than settling the question. 2

Attributions

Associated Religion

Shinto, through the Munakata shrines and the island of Okinoshima that watch the crossing, and Buddhism, which reached Japan from the Korean kingdoms over the same water in the sixth century along with continental ritual practice and Chinese writing. 1

Origins

Origin Region

Between the Japanese archipelago and the Korean peninsula and Russian coast, a nearly enclosed sea entered through narrow straits at each end, the Korea Strait in the south and the Tsugaru, Soya and Tatar straits in the north. 2

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An Island Where Nothing Was Taken Away

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.

The Water Buddhism Crossed, and a Name in Dispute

Everything that reached Japan from the continent before the modern period came across this sea, and the religious cargo was substantial.

Buddhism arrived in the sixth century by way of the Korean kingdom of Baekje, whose ruler sent an image and scriptures to the Japanese court, and the debate at that court about whether to accept a foreign deity is recorded in the chronicles as a dispute between clans. What followed was not simple adoption but a long process of accommodation with the kami, worked out over centuries and eventually formalised in the honji suijaku framework, under which local deities were understood as local manifestations of buddhas. Chinese writing, continental ritual, temple architecture and, later, Zen and the Chinese schools all followed the same route.

Monks travelled in both directions and often at real risk. Ganjin, the Chinese monk who brought the full ordination lineage to Japan in the eighth century, attempted the crossing repeatedly over more than a decade, was shipwrecked and lost his sight before arriving.

The sea's name is itself a live dispute. Korea calls it the East Sea and has argued for decades in international forums that the current name reflects a period of Japanese dominance rather than long usage; Japan maintains that the name is long established and neutral. The atlas records the dispute rather than resolving it, and uses the more widely catalogued form for the row.

Cross-Tradition Connections