Geographical names reflect the history, culture, lifestyle, and philosophy of the people who use them and the name “East Sea” is no exception. “East Sea”, a name deeply rooted in the lives of the Korean people, first appears in a historical document dating back to as early as 59 B.C. In the History of the Three Kingdoms (Samguksagi, 三國史記), the name “East Sea” was used in a chapter on King Dongmyeong, the founder of Koguryeo (one of the three ancient kingdoms in Korea). This proves that the name “East Sea” dates back more than 2000 years, which is 1700 years before the first appearance of the name “Sea of Japan” in Mappamondo, the publication of the Italian missionary Matteo Ricci in 1602.
There are various other historical references to the “East Sea” thereafter. Another noteworthy example of use of the name “East Sea” is the inscription on the stele of King Gwanggaeto of the Goguryeo kingdom in 414 A.D.. Since the territory of Goguryeo at that time extended as far as Manchuria in China, the name “East Sea” encompassed the sea not only east of the Korean Peninsula but east of the entire Eurasian continent as well.
The oldest remaining map in Korea that officially used the name “East Sea” is the Map of Eight Provinces of Korea (Paldo-Chongdo, 八道總圖) in the Newly Expanded Survey on the Geography of Korea (Sinjeung Dongguk Yeoji-Seungnam, 新增東國輿地勝覽) compiled by an order of the king in 1531. Subsequent maps also clearly specify the name “East Sea”. Examples from the late 18th century include the General Map of Korea (Ahguk Chongdo, 我國摠圖) found in Maps of the World (Yeojido, 輿地圖) and the Map of Joseon-Japan-Ryukyu Islands (朝鮮日本琉球國圖).
Japanese historical records and geographical books reveal that the name “Sea of Japan” did not appear until the late 18th century. Even Japanese scholars acknowledge the fact that it was a Westerner Matteo Ricci, not a Japanese person, who first used the name in 1602. For the Japanese people, the sea was simply a nameless body of water until the beginning of the 17th century.
Moreover, there are a number of historical documents showing that the sea area was called the “Sea of Joseon” among the Japanese rather than the “Sea of Japan”. Even official maps produced by the Japanese government during the 18th and 19th century refer to the sea as the “Sea of Joseon”. This refutes Japan’s argument that the Japanese simply adopted the name “Sea of Japan” because it was already predominantly used by Westerners in the late 18th and early 19th century.