East Sea is a sea, bordered by Korea to the west, and Japan to the east and south. 

'East Sea' has been used for a long time. 

Especially Korean people have used it over 2,000 years. 

Many ancient maps consistently say this area is "East Sea".

In contrast, 'Sea of Japan' never used in map up to the 18th century.

In early 20th century, East Sea was eliminated from maps of the world, when Japan invaded Korea.