The government is calling on citizens abroad to contact Japanese diplomatic missions if they find a map showing the Sea of Japan labeled as the East Sea, the name favored by South Korea.
The request, coming amid a dispute between Tokyo and Seoul over the name, is aimed at having publishers "correct" the labeling to Japan's preference. But it remains unclear whether any publisher would comply with such a request, and the government is likely to find it hard to sell its case.
The Foreign Ministry is making a similar bid for a pair of rocky islets controlled by South Korea in the same body of water. Japan calls the islets Takeshima and South Korea calls them Dokdo. South Korea is actively seeking international recognition for both East Sea and Dokdo.
South Korea has long demanded that the waters be called the East Sea, arguing that the term Sea of Japan only became popular globally after Japan's contentious annexation of the peninsula in 1910.
Japan claims the term Sea of Japan has been in use internationally since the 19th century, before it asserted colonial rule over the peninsula.
In 2012, the International Hydrographic Organization decided to continue calling the body of water the Sea of Japan because it is internationally recognized.
South Korea and Japan have been contesting the sovereignty of the islets since the early 1950s, when Seoul placed a small armed force there in 1954. Tokyo accuses Seoul of illegally occupying them.