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Sea of Japan
A deep marginal sea cradled between Asia and the Japanese archipelago
The Sea of Japan — called the East Sea on the Korean peninsula — is the deep, almost enclosed basin held between the Japanese islands and the Asian mainland. Cut off from the open Pacific by Japan and from neighbouring seas by shallow straits, it behaves like a small ocean of its own, with its own currents, its own deep water, and a climate that buries Japan's west coast under some of the heaviest snowfall on Earth. Its very name remains a matter of dispute among the nations that share it.
Covering roughly 978,000 square kilometres and reaching about 3,742 metres at its deepest, the sea is connected to the wider ocean only through narrow, shallow straits — the Korea Strait in the south and the Tsugaru and Soya straits in the north. The warm Tsushima Current flows up its eastern side while colder water hugs the Asian coast, and the moisture this warm water gives up to frigid Siberian winds produces the famous snowfalls of Honshu's Sea-of-Japan coast. Its near-isolation gives it a distinctive, oxygen-rich deep layer found in few other seas.
These waters have been a corridor between the Asian mainland and the Japanese islands for thousands of years, carrying Buddhism, writing, and rice cultivation eastward and shaping the early Japanese state. In modern times the sea has been a theatre of naval power — the decisive Battle of Tsushima was fought here in 1905 — and remains strategically sensitive, bordered by Russia, the two Koreas, and Japan. Its rich fisheries and the lingering name controversy keep it firmly in the regional spotlight.