The Korean Peninsula is surrounded by water on three sides, and is connected to China to the north. As South Korea is located at the gateway to the continent, it has a long history of active trading through the ocean. Through the centuries, Korean navigation techniques involving tidal currents, ocean currents, and wind have been more advanced than what was widely known. Korean seas have complicated physical, chemical, and geological factors—such as seasonal ocean currents, tides, and complex topographical features—nd have a range of marine habitats with unique ecological communities.

  The Yellow Sea, which extends into the East China Sea, is characterized by shallow water less than 80 m deep and gently sloping submarine topography. It is named after its yellowish color, which arises from sediment-rich river water from the Yangtze and the Yellow River of the Chinese mainland.

  The Korea Strait separates Korea and Japan. It is greatly affected by changes in the warm Kuroshio Current, which flows northward, bringing warm waters to Japan. Other ocean currents are shown on the map at left, warm currents in red and cold in blue.
 

  The east coast has a relatively simple coastline with deep water that reaches depths of 2,000–,000 m. It has well-developed, narrow beaches, but the steep slopes of coastal and seabed topography prevent the development of tidal flats and continental shelves. The Tsushima Current—hich flows into the East Sea through the Korea Strait—preads along the surface of the East Sea.