In 1949, the dictator of the newly formed Democratic People's Republic of Korea, Kim Il-sung, traveled to Moscow to meet with Stalin and seek political support for a future invasion of the South. The Russian dictator did not oppose the idea, as an invasion seemed to carry minimal risk. A war on the Korean Peninsula would divert U.S. attention away from Europe and, if successful, would expand the Soviet bloc’s buffer zone. Stalin agreed to support the plan on the condition that Mao also provided assistance if necessary.  

Following Kim’s visit to Beijing, North Korea received the green light from China. However, the USSR refused to supply Kim with state-of-the-art weaponry, instead selling him the arms that the Red Army had abandoned in Korea after the occupation. After consulting with a Soviet military team on strategy, the operation was set in motion; all parties involved were so confident in victory that no alternative plan was developed.  

On June 25, 1950, heavy bombardments began, and North Korean forces overwhelmed the South’s troops, quickly occupying almost the entire peninsula. President Truman appealed to the United Nations, requesting a resolution to authorize U.S. intervention. On July 7, the UN Security Council established a unified military command under U.S. leadership, placing General MacArthur in charge. The American general successfully executed an amphibious landing at Incheon, striking behind enemy lines and turning the tide of the conflict.  

UN forces pushed beyond the demarcation line, advancing toward the Chinese border. China had previously warned that crossing this boundary would prompt its intervention, and ultimately, it secretly deployed a contingent of 260,000 "volunteers."  

In 1953, an armistice was signed by China, North Korea, and the United Nations. However, South Korea refused to sign, rejecting the division as permanent. Legally, North and South Korea remain at war to this day.