First, the term ¡°East Sea¡± is historical. ¡°East Sea¡± has been used for more than 2,000 years on the Korean Peninsula. The first record of ¡°East Sea¡± was in The History of the Three Kingdoms and the Saga of King Dong-myeong written around 59 B.C. Furthermore, the term ¡°East Sea¡± has been used widely around the world since the eighteenth century.
Second, the term ¡°East Sea¡± is universal. The East Sea, or the Sea of Japan as the document illustrates, borders Korea, Japan, Russia, et cetera. So, it is not just Japan¡¯s sea, but a sea that a lot of countries share. Meanwhile, the term ¡°East Sea¡± is not one-sided like the ¡°Sea of Japan¡± is, as it refers to a sea that is on the east side of the Asia continent.
Third, the name ¡°Sea of Japan¡± is a vestige of Japanese Imperialism. The term has been started to spread to the world during the Japanese Occupation of the Korean Peninsula. Before then, it was more popular to use the ¡°East Sea¡± or the ¡°Sea of Korea." However, as Japan¡¯s global position became stronger and it ruled over Korea, the Korean writing system was made illegal, forcing Koreans to use only Japanese. At this time, Korean place names were changed to Japanese-style, including the ¡°Sea of Japan."
Fourth, international law recommends writing the ¡°East Sea¡± and the ¡°Sea of Japan" together. For example, UNCSGN Resolution III/20 states that if countries concerned failed to agree on a common name, it should be a general rule of international cartography to accept all the different names.
Fifth, many maps are writing the term ¡°East Sea¡± in parallel with the ¡°Sea of Japan." The Atlas is an example. On its map titled ¡°Singapore and the world¡± by Pearson Education South Asia in 2008, both terms were used.