Though I suppose they'd better get it right, since it looks to be a paid advertisement for Seoul.
Though the English name is Sea of Japan, most Koreans---85% according to one survey---are convinced it ought to be called the East Sea in English, rather than simply 동해 in Korean. One of the men leading the charge is Kim Jang-hoon. He's Korean singer who has taken out a number of advertisements in big American newspapers professing to "correct" the erroneous English that labeled the Sea of Japan . . . well, the Sea of Japan, in what's about the only time you'll see "Korean," "correct," and "English" in the same sentence. His most recent campaign was in August, during which he placed ads that read in part
There is no Sea of Japan in the world.
Except in popular usage, I guess. Here are some comments today from Kim, your authority on the English language, from a post on his Cyworld page:
Thank you for WSJ
. . .
East Sea/Sea of japan
. . .
정말 눈물이 날만큼 기쁩니다.
. . .
'Truth wins,in thw end'
Clearly, if Kim wants to "correct" English, he ought to start with his own, and the Gibberlish that gets used in pop songs, advertisements, and t-shirts.