After secretly crossing the Yalu River on October 19th, 1950, the Peoples Volunteer Army (PVA) 13th Army Group launched the First Phase Offensive on October 25th, attacking the advancing UN forces near the Sino-Korean border. This military decision made solely by China changed the attitude of the Soviet Union. Twelve days after PVA troops entered the war, Stalin allowed the Soviet Air Force to provide air cover and supported more aid to China. After inflicting heavy losses on the ROK II Corps at the Battle of Oniong, the first confrontation between Chinese and US military occurred on November 1st, 1950. Deep in North Korea, thousands of soldiers from the PVA 39th Army, encircled and attacked the US 8th Cavalry Regiment with three-prong assaults—from the north, northwest, and west—and overran the defensive position flanks in the Battle of Unsan. The surprise assault resulted in the UN forces retreating back to the Ch’ongch’on River, while the PVA unexpectedly disappeared into mountain hideouts following victory. It is unclear why the Chinese did not press the attack and follow up their victory.

The UN Command, however, were unconvinced that the Chinese had openly intervened because of the sudden PVA withdrawal. On 24 November, the Home-by-Christmas Offensive was launched with the US Eighth Army advancing in northwest Korea, while US X Corps attacked along the Korean east coast. But the PVA were waiting in ambush with their Second Phase Offensive, which they executed at two sectors: in the East at the Chosin Reservoir and in the Western sector at Ch’ongch’on River.

On November 13th, Mao appointed Zhou Enlai the overall commander and coordinator of the war effort, with Peng as field commander. On November 25th, on the Korean western front, the PVA 13th Army Group attacked and overran the ROK II Corps at the Battle of the Ch’ongch’on River, and then inflicted heavy losses on the US 2nd Infantry Division on the UN forces’ right flank. Believing that they could not hold against the PVA the Eighth Army began to retreat from North Korea crossing the 38th Parallel in mid-December. UN morale hit rock bottom when Lieutenant General Walton Walker, commander of the US Eighth Army, was killed on December 23rd, 1950, in an automobile accident.

In the east, on November 27th, the PVA 9th Army Group initiated the Battle of Chosin Reservoir. Here the UN forces fared comparatively better: like the Eighth Army the surprise attack also forced X Corps to retreat from northeast Korea, but they were in the process able to break out from the attempted encirclement by the PVA and execute a successful tactical withdrawal. X Corps managed to establish a defensive perimeter at the port city of Hungnam on 11 December and were able to evacuate by 24 December in order to reinforce the badly depleted US Eighth Army to the south. During the evacuation, about 193 shiploads of UN forces and matériel (approximately 105,000 soldiers, 98,000 civilians, 17,500 vehicles, and 350,000 tons of supplies) were evacuated to Pusan. The SS Meredith Victory was noted for evacuating 14,000 refugees, the largest rescue operation by a single ship, even though it was designed to hold 12 passengers. Before escaping, the UN forces razed most of Hungnam city, with particular attention to the port facilities. The UN retreat from North Korea also saw the massive evacuation from the capital city of Pyongyang. In early December, UN forces, including the British Army’s 29th Infantry Brigade, evacuated Pyongyang, along with large numbers of refugees. Around 4.5 million North Koreans are estimated to have fled from North Korea to either the South or elsewhere abroad. On 16 December 1950, President Truman declared a national state of emergency with Presidential Proclamation No. 2914, 3 C.F.R. 99 (1953), which remained in force until 14 September 1978. The next day, 17 December 1950, Kim Il-sung was deprived of the right of command of KPA by China.

China justified its entry into the war as a response to “American aggression in the guise of the UN”. Later, the Chinese claimed that US bombers had violated PRC national airspace on three separate occasions and attacked Chinese targets before China intervened.

Dragon has announced their own plans for Chinese intervention with two versions of a People’s Volunteer Army T-34/85 medium tank, both of which are due out in early 2023.