A South Korean civic group purchased a half-page advertisement that appeared in Friday's China Youth Daily that called for renaming the Sea of Japan as the "East Sea".

The ad, which ran in black and white on page seven of the newspaper, was headlined "Do You Know?" and said the body of water between South Korea and Japan "has been called 'East Sea' for 1,000 years".

"A lot of evidence is found in old maps of China and Europe. Even in old maps of Japan, sometimes the sea was marked as 'the Sea of Corea', 'Corean Sea' or 'Mer de Core'," it said.