A Korean American collector has unveiled 50 ancient maps that label the sea between South Korea and Japan as the "Sea of Korea."

Yoon Sam-kyoon, the president of the private cultural foundation Korea Heritage in Washington, made public some 50 maps he has been collecting over the past 20 years. Most of the maps were produced in Britain or France two to three hundred years ago.

One of them is a map of Korea, China and Japan that dates back to 1552. The map labels the East Sea as the "Sea of Korea." The map also shows Japan’s Tsushima Island as a separate territory from that of Japan.

President Yoon says based on the maps, the distorted term “Sea of Japan” was not used in the international community before the 19th century. He stressed that such a fact is vital in the dispute over the sovereignty of the Dokdo islets.