Second Phase Offensive

In late 1950, the United Nations military forces, led by the United States, advanced rapidly north through South Korea with only light resistance from the retreating North Korean Korean People's Army (KPA). On 3 October MacArthur announced that UN forces had crossed the border into North Korea. In early October 1950, after reports that UN forces were crossing the border into North Korea, Chinese leader Mao Zedong notified Soviet Union leader Joseph Stalin that "We have decided to send troops into Korea...to fight the United States...this is necessary because, should the Americans occupy the whole of Korea, the Korean revolutionary force would be completely destroyed and the American invaders would become more rampant." Mao said that China would infiltrate 12 infantry divisions into North Korea and that another 24 infantry divisions were present in northern China (Manchuria) for deployment if necessary. A Chinese infantry division when fully staffed numbered about 10,000 men. Infiltration and opening shots On 19 October, tens of thousands of Chinese soldiers began crossing the Yalu River, the border between China and North Korea, at night to avoid detection by UN reconnaissance aircraft. Their entry was undetected. On 25 October the first shots fired between the PVA and UN forces were at the Battle of Onjong, about south of the Yalu. Nine Chinese armies and 30 divisions were in North Korea when the Second Phase Offensive began. The total number of PVA soldiers has been estimated at upwards of 300,000. Few KPA soldiers were involved in the offensive. Eighteen divisions were allocated for the western offensive, the Battle of the Ch'ongch'on River, and 12 divisions were allocated for the eastern offensive, the Battle of Chosin Reservoir. UN forces and strategy The UN military forces consisted of two components, the Eighth United States Army on the western side of the Korean peninsula and X Corps on the eastern side. The rugged Nangnim Mountains and Taebaek Mountains and a "worrisome" gap separated the two components. On 24 November 1950, the Eighth Army occupied a line about long stretching west to east from the Yellow Sea across the broad coastal plain of the Ch'ongch'on River to the ridges of the Taebaek Mountains. The Eighth Army charged with carrying out the Home for Christmas offensive consisted of four U.S. infantry divisions, eight Republic of Korea Army (ROK) divisions, Turkish and British brigades and a number of smaller units of the United States and several other countries. The U.S. divisions occupied the western section of the line, a mostly flat area, while the ROK occupied the hilly and mountainous eastern section of the line. Although less numerous than the PVA who may have numbered as many as 240,000 soldiers, the 130,000 front-line soldiers of the Eighth Army "with modern communications, ample artillery support, tanks and backed by adequate logistic support" were "not significantly inferior in terms of combat power to the much more numerous but primitive Chinese." However, the ROK divisions on the right side of the UN line were notably inferior to U.S. divisions, having fewer men and less artillery and having suffered heavy casualties during the First Phase Offensive. The replacements for those casualties were largely new recruits. UN forces in X Corps comprised five infantry divisions: the U.S. 1st Marine Division, the U.S. 3rd and 7th Infantry Divisions and two ROK divisions, altogether along with attached units totaling about 90,000 men. They would face PVA armies numbering up to 150,000. The U.S. Army and ROK divisions were primarily blocking roads and advancing with little resistance in northeastern North Korea and protecting the important supply ports of Wonsan and Hungnam. One element of the 7th Division had already reached the Yalu River by 24 November, the starting date of the Home-by-Christmas offensive. The Chinese offensive in the east was directed primarily against the Chosin Reservoir (called Changjin in Korean) targeting the 1st Marine Division, located west and south of the Reservoir and U.S. army units named Task Force Faith, east of the Reservoir. The UN plan was for the Marines to push westward from Chosin Reservoir across the mountains to hook up with the advancing Eighth Army and close the gap between the two components of the UN offensive. In the days leading up to the start of the Chinese Second Phase Offensive, both 8th Army Commander General Walton Walker and U.S. 1st Marine Division Commander General Oliver P. Smith were wary of advancing as rapidly as MacArthur's headquarters in Japan urged them to do. Smith, in particular, had resisted the exhortations by X Corps commander General Edward Almond to move forward more quickly. Smith ensured that his Marine units were consolidated and mutually supportive. On the west, Walker was also warning his troops of the dangers of advancing carelessly against what seemed to many like an enemy of inferior numbers in a defensive posture. ==Offensive==

The Chinese strike The Second Phase Offensive began when the Chinese attacked the Eighth Army on 25 November. "Rarely has so large an army had such an element of surprise against its adversary. The Americans on the west coast...were essentially blind to the trap they had walked into," said author David Halberstam. Casualties among both UN and PVA troops caused by frostbite were as numerous as those caused by combat. In U.S. Marine Corps lore, the battle is often referred to as "Frozen Chosin." Casualties The PVA suffered about 30,700 casualties from battles and 50,000 from non-battle causes, mostly frostbite. ==Aftermath==

On 28 November 1950, shortly after the onset of the Chinese Second Phase Offensive, MacArthur cabled the U.S. government in Washington that, "We face an entirely new war." The reversal of fortunes in the Korea War was a shock to the military and political leaders of the United States. The U.S. contemplated that it might have to withdraw its military forces from Korea. Immediately given up was the idea that the two Koreas could be united into a single pro-U.S./UN country. The successful evacuation of UN forces by Christmas from Chosin bolstered U.S. confidence, but in a directive to MacArthur on 29 December 1950, the Joint Chiefs of Staff in Washington, instructed MacArthur to "resist aggression" but added that "Korea is not the place to fight a major war." MacArthur was told "to defend...inflicting such damage to hostile forces in Korea as is possible, subject to the primary consideration of the safety of your troops." The Chinese were pleased with the outcome of their Second Phase Offensive, having regained nearly all of North Korea from UN forces. However, the Chinese victory created the opinion among Chinese leaders that "we can defeat American armed forces." As a consequence of this confidence, the Chinese soon launched offensives into South Korea that would be turned back by the UN. By early 1951, the Korean War had turned into a stalemate and China had given up carrying out large-scale offensives. == Notes ==