Marginal sea

A marginal sea is on the boundary of a continent and not wholly connected to the ocean.

Physical structures that a marginal sea has in between the marginal sea and the continent and/or the ocean are:

• Dividers like islands, archipelagos, or peninsula.
• Connections like straits, channels, or waterways.

Through waves and currents, the water in a marginal sea flows into an ocean, and vice versa.

Marginal seas have been explored frequently by maritime nations, especially for trade. Constant piracy have been existing in some marginal seas where government control have been ineffective. Marginal seas, as territories, are often under disputed.

Especially in terminology of geography studies in East Asia, marginal seas are classified in two ways:

1. Vertical marginal seas (縱邊緣海): the long (main) axis parallels to the fault of the nearest land.

   Typical examples are:

   • The Bering Sea (separated from the ocean by the Aleutian Islands)
   • The Sea of Japan (by Japan)
   • The Sea of Okhotsk (by the Kurile Islands)
2. Horizontal marginal seas (橫邊緣海): the long axis is approximately perpendicular to the fault.
   • The North Sea (by Great Britain)

There are three marginal seas (邊緣海 or 半封閉海) around China (listed in order of size):

1. The South China Sea (Horizontal) (by Southeast Asian islands)
2. The East China Sea (Vertical) (by Ryukyu)
3. The Yellow Sea (Vertical) (by Korea)

Seas which are barely marginal include the Tasman Sea. Seas which are not marginal include the Arabian Sea.