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.

Seoul and Tokyo have locked horns for decades over the name of the body of water, with Seoul calling it the "East Sea" while Tokyo uses the name "Sea of Japan".

The ad was illustrated with a map of Northeast Asia, with the waters marked as the "East Sea".

The South Korean Yonhap News Agency said the ad was designed by Seo Kyoung-duk, a professor at Sungshin Women's University in Seoul.

"We are making efforts to promote the new name. Hopefully, more Asian countries will take this opportunity to adopt the name of 'East Sea'," the ad said.

"China and South Korea should join hands to strive for peace and prosperity of Northeast Asia in the 21st century," it added.