At your website, I found out that the body of water which lcoates between the Korean peninsula and Japan is mentioned as Sea of Japan.
As you know, there has been a long dispute between Korea and Japan regarding the name of sea. In other words, how the name of location is a very sensitive issue. According to the resolution made in UN and other international organizations, the appellation of a shared geographical feature must be written side-by-side if the countries directly involved cannot make settlement.
Therefore, as a member of the campaign I urge you to use the proper designation method of the area, which is East Sea/Sea of Japan. It is because there has been no consent between South Korea and Japan regarding it. To read full sentences of these gists, please visit this website at:
http://www.prkorea.com/english/e_truth/e_truth3_3.htm
Once Korea and Japan agree on a common designation, that is in accord with the general rule of international cartography, we will then follow the agreed-on designation.