An independent kingdom since the peninsula was unified in 668, Korea in the nineteenth century became the focus of a regional struggle for dominance among the major powers in East Asia: China, Japan, and Russia. By 1905, Japan had managed to defeat its rivals in two major wars and to occupy Korea, which it colonized in 1910.
Korea remained a colony until the Allies defeated Japan in World War II, when the country was divided in half, roughly along the thirty-eighth parallel. In 1948 the southern part, which had been liberated by the United States, became the Republic of Korea (South Korea); the northern part, liberated by the Russians, became the Democratic People’s Republic of Korea (North Korea).
On June 25, 1950, North Korea invaded South Korea in an attempt to reunify the peninsula under a communist government. The United States enlisted the support of the United Nations to defend the government of South Korea. U.N. forces, together with the South Korean army, halted the initial North Korean advance. Nevertheless, in 1951, when China entered the war in support of North Korea, the communist armies pushed the U.N. forces back to the previous division along the thirty-eighth parallel. After a long stalemate, an armistice was signed in 1953.
Yet, even today, the war is not officially over. Around 28,500 American troops remain in South Korea. Although there is a strong desire in both South Korea and North Korea for reunification, the two countries remain divided.