The term ¡°East Sea¡± has been used for more than 2000 years in Korea, numerous historical documents proving this statement. On the other hand, the term ¡°Sea of Japan¡± was only birthed in the recent past. By the 19 century, even maps of Japan referred to the sea between the Korea and Japan, ¡°Sea of Joseon(Korea)¡±.
It was only when Japan rose to power, and Korea secluded itself from western countries that ¡°Sea of Japan¡± was used. As Korean became a victim of Japan¡¯s imperialism, Japan tried to deprive Korea of its identity by taking away everything that composed a 'korean': sovereignty, various rights, language, tradition and more. During that time, the term "Sea of Japan" became used worldwide. However, after World War II, because of the Cairo Declaration, Potsdam Declaration, Supreme Commander for the Allied Powers, and the Treaty of Peace with Japan, the territories forcefully claimed were to be recovered by Korea. Thus, by all rights, the terms should have changed back to what they were. However, it was not to be because Japan claimed that Dokdo was theirs.
One might think the terms have no significance or that the naming of the sea and the sovereignty over Dokdo are irrelevant matters. However, this is a sure vestige of Janpanese imperialism.It seems unreasonable to use the name "Sea of Japan" which is decided in the period of imperialism because its original name is "East Sea" which has been used throughout history.