The triumph of the communist revolution in China on October 1, 1949 completely altered the geostrategic balance of East Asia. Stalin, who had suffered serious setbacks in Europe, wanted to regain ground in Asia and gave his approval for a North Korean attack on South Korea. Meanwhile, the campaign of destabilization in South Korea against the president, accused of dictatorship, generated revolts in the pro-communist sectors of the peasantry and unions, which initiated a wave of assassinations and attacks that were harshly repressed by the government, unleashing a virtual civil war in the south.
Taking advantage of the climate of insecurity and instability of the South, on June 25, 1950, the North Korean troops crossed the 38th parallel and advanced towards the south, virtually destroying the South Korean forces, which could barely retreat around Pusan, with the intention to achieve a quick victory before the reaction of the Western democratic powers. With this event, the Korean War began.