Issue of the Name of the Sea of Japan
Study of maps possessed by the United States Library of Congress

August 2005

From December 2004 to March 2005, the Ministry of Foreign Affairs of Japan conducted a study with regard to the naming of the maritime region of the Sea of Japan on the maps possessed by the United States Library of Congress that were published between the 14th and 19th century.

The findings of the study show that of the 1,435 maps [PDF] for which a name is recorded for the region of the Sea of Japan, 77% bear the name "Sea of Japan." Moreover, this study shows that of the maps published in the 19th century, 82.4%, or 1,059 maps, bear the name as "Sea of Japan." The study makes clear that of the maps published in the 19th century, in particular out of a total of 563 maps that were published while Japan was still in its policy of isolation from the rest of the world, a total of 74% or 417 bear the name "Sea of Japan." These findings reaffirm that "the name 'Sea of Japan' became established in Europe and the U.S.A. from the beginning of the 19th century at a time when Japan was still under its policy of isolation, being unable to exert international influence."

(Note: The Republic of Korea (ROK) has asserted that "the name the 'Sea of Japan' came into dominant use as a result of Japan's imperialism and colonialism during the first half of the 20th century." The ROK cites the results of an independently implemented study of the antique maps held by the United States Library of Congress as the basis for this assertion. According to this independent study, the ROK states a name is recorded for the region of the Sea of Japan on 103 maps, of which 68, or 66% bear the name "Sea of Korea" or "East Sea," and only 14, or 14% bear the name "Sea of Japan.")