A Japanese organization combating online pirated manga has estimated that losses from the illegal versions reached the worst monthly level in November.
The Authorized Books of Japan, or ABJ, says websites showing pirated titles have been cropping up.
South Korean Foreign Minister Kang Kyung-wha says she has asked UNESCO to consider removing a group of Japanese industrial sites from its World Heritage list.
Kang told reporters on Tuesday that she sent a letter to UNESCO Director-General Audrey Azoulay the previous day.
Shrines designated as UNESCO World Heritage sites in Tochigi Prefecture's Nikko, north of Tokyo, have temporarily closed to prevent infections of the new coronavirus.
Toshogu Shrine, Rinnoji Temple and Futarasan Shrine made the announcements on Monday.