Korea Strait (Japanese, Chosen Kaikyo), channel of the northwest Pacific Ocean connecting the East Sea (Sea of Japan) in the northeast with the East China Sea in the south. It separates the southeastern side of the Korea Peninsula from the Japanese islands of Kyūshū and Honshū. The strait is 180 km (110 mi) wide and about 90 m (about 300 ft) deep. It contains the islands of Tsushima. The section of the strait to the southeast of these islands is also known as Tsushima Strait, and the name Korea Strait is sometimes used to refer only to the 100 km (60 mi) of water west of the islands. The strait was the scene of a battle from May 27 to May 29, 1905, during the Russo-Japanese War, in which most of a Russian fleet was destroyed or captured.