The Korean War was a war between North Koreaball and South Koreaball, in which a UNball force led by the USAball fought for the South, and Chinaball fought for the North, which was also assisted by the Sovietball. The war arose from the division of Korea at the end of World War II and from the global tensions of the Cold War that developed immediately afterwards. It officially ended in 27 April 2018 after 2018 inter-Korean summit.
After the first two months of the conflict, South Koreaball's forces were at the point of defeat, forced back to the Busanball's Perimeter. In September 1950, an amphibious UN counter-offensive was launched at Incheonball, and cut off many of the North Korean attackers. Those that escaped envelopment and capture were rapidly forced back north all the way to the Chinese border at the Yalu River, or into the mountainous interior.
At this point, on October 1950, Chinese forces crossed the Yalu and entered the war. Chinese intervention triggered a retreat of UN forces which continued until mid-1951, and re-captured Seoulball with the Chinese New Year's Offensive. After these dramatic reversals of fortune, which saw Seoulball change hands four times, the last two years of conflict became a stalemate. A war of attrition ensued, with the front line close to the 38th parallel.
Armistice and the end of the war
The fighting ended on 27 July 1953, when the armistice was signed. The agreement created the Korean Demilitarized Zone to separate North and South Korea, and allowed the return of prisoners. Clashes have continued to the present.
After the armistice
Since the armistice, there have been numerous incursions and acts of aggression by North Korea. In 1976, the axe murder incident was widely publicized. Since 1974, four incursion tunnels leading to Seoul have been uncovered. In 2010, a North Korean submarine torpedoed and sank the South Korean corvette ROKS Cheonan, resulting in the deaths of 46 sailors. Again in 2010, North Korea fired artillery shells on Yeonpyeong island, killing two military personnel and two civilians.
After a new wave of UN sanctions, on 11 March 2013, North Korea claimed that it had invalidated the 1953 armistice. On 13 March 2013, North Korea confirmed it ended the 1953 Armistice and declared North Korea "is not restrained by the North-South declaration on non-aggression". On 30 March 2013, North Korea stated that it had entered a "state of war" with South Korea and declared that "The long-standing situation of the Korean peninsula being neither at peace nor at war is finally over". Speaking on 4 April 2013, the U.S. Secretary of Defense, Chuck Hagel, informed the press that Pyongyang had "formally informed" the Pentagon that it had "ratified" the potential usage of a nuclear weapon against South Korea, Japan and the United States of America, including Guam and Hawaii. Hagel also stated that the United States would deploy the Terminal High Altitude Area Defense anti-ballistic missile system to Guam, due to a credible and realistic nuclear threat from North Korea.