The National Archives of Korea says it has completed restoring an ancient map that uses the label “Joseon Sea" to refer to the East Sea after 13 months of restoration work.

The archives agency, under the Ministry of Public Administration and Security, said it has returned the map to Seoul National University (SNU).

The map, which dates back to 1810, was made by the Japanese government and is often used to protest Japan’s moves to label the East Sea the “Sea of Japan.”

Measuring 202 centimeters wide and 118 centimeters long, the map is made up of 16 segments. The map was seriously damaged at the time it was obtained by the agency from SNU.