strait instead of the usual twelve, reportedly to allow nuclear-armed United States Navy warships and submarines to transit the strait without violating Japan's prohibition against nuclear weapons in its territory. Naming of the strait Historic impact Land bridge During the Pleistocene glacial cycles, the Korea Strait and the Bering Straits, and the Yellow Sea were often narrowed and the Japanese islands may at times have been connected to the Eurasian Continent through the Korean Peninsula or Sakhalin. At times, the Sea of Japan was said to be a frozen inner lake due to the lack of warm Tsushima Current and various plants and large animals, such as the Palaeoloxodon naumanni are believed to have spread into Japan. Early history Historically, these narrows served as a highway for high risk voyages. The shortest distance between Busan, South Korea, and Tsushima Island is about 50 km, as is the shortest distance from Tsushima to Iki Island, Japan. In the 6th century, Buddhism (Mahāyāna Buddhism) was transmitted by Baekje people to the easternmost Japan of the Emperor Kinmei's era over this strait (See also: East Asian Buddhism and Buddhism in Japan). Mongol invasion A joint Mongol-Korea fleet crossed this strait and attempted to invade Japan in 1274 and 1281. The force severely ravaged the Tsushima Island on the way to Japan but failed to defeat Japan. Wokou and Ōei Invasion After the Mongolian invasion ravaged Tsushima, it became a base of the Wokou (Japanese pirates). The Korean Joseon Dynasty sent a fleet to Tsushima in 1419 for the suppression of Wokou activity. Korea subsequently agreed to grant the Japanese limited trading privileges. Battle of Tsushima The Battle of Tsushima, fought between the Japanese and Russian navies on May 27 and May 28, 1905, took place in the Tsushima Strait part of the Korea Strait, east of the north part of Tsushima and due north of Iki Island. The Russian fleet was destroyed by the Japanese. Battle of Korea Strait The Battle of Korea Strait was a naval battle fought on the first day of the Korean War, 25–26 June 1950, between the navies of South Korea and North Korea. A North Korean troop transport carrying hundreds of soldiers attempted to land its cargo near Busan but was encountered by a South Korean patrol ship and sunk. It was one of the first surface actions of the war and resulted in an important South