History of South Korea
On August 15, 1948, the Republic of Korea was formally established, with Rhee Syngman as the first president. With the establishment of Rhee's government, de jure sovereignty also passed into the new government. On September 9, 1948, a communist regime, the Democratic People's Republic of Korea (North Korea), was proclaimed under Kim Il-sung. However, on December 12, 1948, by its resolution 195 in the Third General Assembly, the United Nations recognized the Republic of Korea as the sole legal government of Korea.
History of Japan–Korea relations
Since 1945, relations involve three states: North Korea, South Korea and Japan. Japan cut off Korea from Qing Chinese suzerainty and for Japan, a high priority in the late 19th century, fighting wars with those two countries on the issue. Japan took control of Korea with the Japan-Korea Annexation Treaty of 1910. When Japan was defeated in World War II, Soviet forces took control of the North, and American forces took control of the South, with the 38th parallel as the agreed-upon dividing line. South Korea became independent as of August 15, 1945, and North Korea as of September 9, 1945. In June 1950, North Korea invaded and almost conquered South Korea, but was driven back by the United Nations command, leading South Korean, American, European and international forces. North Korea was nearly captured, with the United Nations intending to rollback Communism there. However, China entered the war, pushed the UN forces out of North Korea, and a military stalemate resulted along the lines similar to the 38th parallel. An armistice was agreed on in 1953, which is still in effect, and the cease-fire line of that year remains the boundary between North and South.