On January 18 of 1952, Republic of Korea President Syngman Rhee issued a “proclamation of sovereignty over adjacent seas.” The proclamation stated that South Korea was establishing its maritime zone in order to protect natural and marine resources, as well as minerals surrounding the Korean Peninsula. This maritime zone extends into the high seas and includes Takeshima within its scope. (Ref.1)

On January 28 of 1951, the Japanese Government protested the Korean Government’s illegal demarcation of the high seas, and stated that “Furthermore, in the proclamation the Republic of Korea appears to assume territorial rights over the islets in the Japan Sea known as Takeshima (otherwise known as Liancourt Rocks). The Japanese Government does not recognize any such assumption or claim by the Republic of Korea concerning these islets which are without question Japanese territory.” (Ref.2)

Ref. 1: Proclamation of sovereignty over adjacent seas by Republic of Korea President Syngman Rhee, “Chronological Table and Key Documents Relating to Japanese Diplomacy,” Vol. 1, ‘Official Gazette,’ Special Issue, January 18, 1952, pp.471-472 (Korean)

Ref. 2: “Takeshima Mondai no Keii” (Events leading up to the Takeshima Issue), “Kaigai Chosa Geppo” (Monthly report for overseas surveys) Vol. 4 No. 11, November of 1954, p.66

Related documents
“Rishoban Line to Kankoku Seifu” (The Syngman Rhee Line and the Korean Government), Dai 2-ki Takeshima Mondai ni Kansuru Chosakenkyu Saishu Hokokusho (Final Report of the Research Study on the Takeshima Issue: 2nd Period), 2012, pp.79-97.

“Note Verbale of January 28, 1952,” Foreign Ministry [ROK], Collection of Dokdo-Related Materials (I): The Diplomatic Correspondences (1952-76), 1977, pp.1-2 (Shimane Prefectural Government homepage)