Korean War

The Korean War is a war between North Korea (Democratic People’s Republic of Korea, DPRK) and South Korea (Republic of Korea, ROK) that started on 25 June 1950 and paused with an armistice signed 27 July, 1953. To date, the war has not been officially ended through treaty, and occasional skirmishes have been reported in the border region.
The Korean peninsula was politically divided as a legacy of the geopolitics of defeating the Japanese Empire on the peninsula in 1945. Soviet forces fighting the Japanese advanced up to the 38th Parallel, which later became the political border between the two Koreas. Despite talks in the months preceding open warfare, continual cross-border skirmishes and raids at the 38th Parallel, and the political frustration of failed all-Korea elections in 1948, escalated to warfare.[31] The reunification negotiations ceased when North Korea invaded South Korea on 25 June 1950.[32]
The United States and the United Nations intervened on the side of the South. After a rapid UN counteroffensive that repelled North Koreans past the 38th Parallel and almost to the Yalu River, the People's Republic of China (PRC) came to the aid of the North.[32] With the PRC's entry into the conflict, the fighting eventually ceased with an armistice that restored the original border between the Koreas at the 38th Parallel and created the Korean Demilitarized Zone, a 2.5 mile wide buffer zone between the two Koreas. North Korea unilaterally withdrew from the armistice on 27 May 2009, thus returning to a de facto state of war; as of this date, no conflicts have erupted.[33]
During the war, both North and South Korea were sponsored by external powers, thus facilitating the war's metamorphosis from a simple civil war to a proxy war between power involved in the larger Cold War.
From a military science perspective, the Korean War combined strategies and tactics of World War I and World War II — swift infantry attacks followed by air bombing raids. The initial mobile campaign transitioned to trench warfare, lasting from January 1951 until the 1953 border stalemate and armistice.