Northeast Asian History Network

On August 15, 1945, Japan declared unconditional surrender, and the Japanese government made an official announcement to abide by the terms expressed in the Potsdam Declaration. After the Japanese Instrument of Surrender formalized the surrender of the Empire of Japan, the SCAP headquarters was established in Tokyo in order to oversee the Allied occupation.
To enforce the various provisions of the Cairo Declaration and the Potsdam Declaration, SCAP began dismantling the Empire of Japan. On January 29, 1946, the SCAPIN 677 was issued. It included a total of eight provisions.
The contents of the statement defined the scope of Japanese domain to be the four main islands of Japan (Hokkaido, Honshu, Kyushu, and Shikoku) and approximately 1,000 smaller adjacent islands. Furthermore, Section 3 expressly excluded Ulleungdo, Dokdo, and Jejudo from Japanese territory. Dokdo is clearly marked as Korean territory in the map attached to this statement.
The SCAPIN 677 expressly excludes Dokdo from Japanese territory. Not soon after, the Government of the Republic of Korea was established, and the contents of the SCAPIN 677 remained intact until the United States military transferred control to the Korean government. Thus, the Government of the Republic of Korea received control over Dokdo as part of the Korean territory from the United States military.

President Syngman Rhee established the Peace Line in 1952![Teacher Notes]

The gap in technology between the Korean and Japanese fishing industries was wide at the time of Korea’s independence. The so-called MacArthur Line was promptly established as a response to the over-fishing by Japanese. Section 3 of SCAPIN 1033 expressly prohibited Japanese vessels from being within 12 nautical miles of Dokdo.
On several occasions, Japan called for adjustment or abolition of the MacArthur Line. The MacArthur Line continued to be adjusted, and when it seemed that it might be abolished, the Korean government devised a countermeasure. That came to be known as the Peace Line.
President Syngman Rhee released a statement opposing the expansion of Japan’s fishing grounds, and on April 24, 1951, the Korean National Assembly adopted a resolution in opposition of adjusting the MacArthur Line. Then in November 1951, a peace treaty was formalized between Japan and the Allies. Ahead of its ratification in April 1952, the Korean government established the Peace Line an average distance of 60 miles from the coast on January 18.
With Dokdo as the starting point, an eight nautical mile radius was considered to be territorial waters, and Japanese fishing vessels violating the boundary were seized. On January 28, 1952, Japan countered by criticizing Korea’s actions stating, “A monopoly of the fishing grounds in adjacent seas goes against the global trend, and we do not accept the territorial claims on Takeshima.” In 1965, the establishment of the Japan-Korea Fisheries Agreement created the “Joint Regulation Zone” in place of the Peace Line.