The sea between the Republic of Korea and Japan is called in two ways, the East Sea, and the Sea of Japan. Through negotiations, Korea and Japan agreed to call the sea in both ways. However, Japan is still arguing that it should be only called as the Sea of Japan since the early 20th century, when they tried to expand their territory by colonies.
But, in fact, the name East Sea has been used in Korea for more than 2000 years as illustrated in various references. On the other hand, the name Sea of Japan was first used in 1602 and even the historical records of Japan shows that Japan did not used the term the Sea of Japan for a long time.
Nevertherless, many websites , including yours , these errors are repeating agian and again. It should be called in 'both ways', unless it will be a serious problem between Korea and Japan. So I want to ask you to call the sea in both ways, by including the term the East Sea when writing an article as well.