<P> The division of Korea between North and South Korea was the result of the Allied victory in World War II in 1945, ending the Empire of Japan's 35 - year rule over Korea . The United States and the Soviet Union occupied the country, with the boundary between their zones of control along the 38th parallel . </P> <P> With the onset of the Cold War, negotiations between the United States and the Soviet Union failed to lead to an independent, unified Korea . In 1948, UN-supervised elections were held in the US - occupied south only . This led to the establishment of the Republic of Korea in South Korea, which was promptly followed by the establishment of the Democratic People's Republic of Korea in North Korea . The United States supported the South, the Soviet Union supported the North, and each government claimed sovereignty over the whole Korean peninsula . </P> <P> The subsequent Korean War, which lasted from 1950 to 1953, ended with a stalemate and has left the two Koreas separated by the Korean Demilitarized Zone (DMZ) up to the present day . </P> <P> When the Russo - Japanese War ended in 1905 Korea became a nominal protectorate of Japan, and was annexed by Japan in 1910 . The Korean king Gojong was removed . In the following decades, nationalist and radical groups emerged, mostly in exile, to struggle for independence . Divergent in their outlooks and approaches, these groups failed to unite in one national movement . The Korean Provisional Government in China failed to obtain widespread recognition . </P>

When did north korea split from south korea