The body of water which stands between Japan and the Asian mainland is called the East Sea or the Sea of Japan. The name of this body of water has been a matter of dispute since the end of the Korean War.
Both the North and South Korean governments oppose the use of "Sea of Japan" by the international community, and they brought up the issue during the United Nations Conference on the Standardization of Geographical Names in 1992. Japan claims that their name for the sea bears priority, but South Korea claims that the name "East Sea" has been in use for 2,000 years and that widespread use of "Sea of Japan" tracked with the rise of Japanese imperialism, which included military occupation of Korea.
Korea was not consulted on the name when the International Hydrographic Organization published works providing official names to bodies of water in the early 20th century, despite being one of the nations bordered by the sea.