Foreign relations of South Korea
On January 18, 1952 The first president of South Korea Syngman Rhee declared that the vicinity of Dokdo was a territory of South Korea (Syngman Rhee line). Subsequently, some 3,000 Japanese fishermen who conducted fishery operations in this vicinity were captured. This incident, called the Dai Ichi Daihoumaru Ship case strained relations between South Korea and Japan.
Korean conflict
As a result, two antagonistic states emerged, with diametrically opposed political, economic, and social systems. In South Korea, a general election was held on May 10, 1948. The Republic of Korea (or ROK) was established with Syngman Rhee as President, and formally replaced the US military occupation on August 15. In North Korea, the Democratic People's Republic of Korea (or DPRK) was declared on September 9, with Kim Il-sung, as prime minister. Soviet occupation forces left the DPRK on December 10, 1948. US forces left the ROK the following year, though the US Korean Military Advisory Group remained to train the Republic of Korea Army. The new regimes even adopted different names for Korea: the North choosing "Choson", and the South "Hanguk".