After WW II, Korea was divided in two, with a communist North controlled by the Soviet Union and a capitalist South backed by the United States. The situation escalated immensely when North Korean troops invaded South Korea in the first significant armed conflict in the Cold War.
On this day September 26th, in 1950, the South Korean capitol of Seoul is recaptured by U.N. troops from the North Koreans. The North Korean troops did not have enough resources to maintain the city and were advised by their Chinese allies to withdraw their troops, allowing South Korean forces to recapture the city.
Since the North Koreans were being supplied with military equipment from Soviet Russia they were also working tactically with Soviet commanders. When the North Korean army could not withstand the American air raids, they were forced to retreat, making the Soviet military advisers seem incompetent in Stalin’s eyes.