A marginal sea is a sea bordering a continent and separated from an ocean by any of a variety of features such as: Marginal seas have been exploited by maritime nations, especially for trade purposes. In some parts of the world piracy is a problem where government control is ineffective. Marginal seas, as territories, are often disputed.
In the terminology of geography studies in East Asia, marginal seas are classified in two ways:
- Vertical marginal seas (縱邊緣海): the long (main) axis parallels the coastline of the nearest land.
- Examples are:
- The Bering Sea (separated from the ocean by the Aleutian Islands)
- The Sea of Japan (between China and Japan)
- The Sea of Okhotsk (by the Kurile Islands)
- Horizontal marginal seas (橫邊緣海): the long axis is approximately perpendicular to the coastline.
- The North Sea (by Great Britain)
- The North Sea (by Great Britain)
- The South China Sea (Horizontal) (by Southeast Asian islands)
- The East China Sea (Vertical) (by Ryukyu)
- The Yellow Sea (Vertical) (by Korea)