Straits of Tsushima

Eastern Channel is a channel of the Korea Strait, which lies between Korea and Japan, connecting the Sea of Japan (East Sea), the Yellow sea and the East China Sea. In Japan calling it Tsushima Strait (対馬海峡, Tsushima Kaikyō) from Tsushima island, and claimed the whole Korea Strait, from the Korean Peninsula to Kyushu.

The Eastern Channel, is the broader eastern channel to the east and southeast of Tsushima Island, with the Japanese islands of Honshu to the east and northeast, and Kyushu and the Gotō Islands to the south and southeast. It is narrowest south-east of Shimono-shima, the south end of Tsushima Island proper, constricted there by nearby Iki Island, which lies wholly in the strait near the tip of Honshu. South of that point Japan's Inland Sea mingles its waters through the narrow Kanmon Strait between Honshu and Kyushu, with those of the Eastern Channel, making for some of the busiest sea lanes in the world.

The strait measures approximately 100 kilometres along Tsushima Island and is about 65 kilometres wide at its narrowest. The strait has a depth of about 140 metres and is bounded by the Tsushima Islands to the west through north (of Gotō Islands). Nearby Iki Island lies in the strait about 50 kilometres towards Kyūshū from the southern tip of Kamino-shima (South Island).

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Wikipedia