The Chinese Civil War was fought between the government of the Republic of China, controlled by The Kuomintang and the Communist Party of China lasting intermittently between 1927 and 1949. The final phase of the Chinese Civil War began immediately after the end of World War II, and it lasted until the defeat of the Kuomintang forces, and the proclamation of the Chinese People's Republic in 1949.
In the last month of World War II in East Asia, Soviet forces launched a huge offensive against the Japanese Army in Manchuria and along the Chinese-Mongolian border. This operation destroyed the fighting capability of Japanese Army in just 3 weeks and left the USSR occupying all of Manchuria by the end of the war in a total power vacuum of local Chinese forces.
Under the terms of the Japanese unconditional surrender dictated by the United States, Japanese troops were ordered to surrender to Kuomintang troops and not to the communist Chinese forces, which were present in some of the occupied areas. In Manchuria, however, where the Kuomintang had no forces, the Japanese surrendered to the Soviet Union. Chiang Kai-shek, the Chairman of the National Government, ordered the Japanese troops to remain at their post to receive the Kuomintang and not surrender their arms to the Communists. However, during the soviet occupation of Manchuria, they gave to the Chinese Communists most of the Japanese weapons that were captured.
The first post-war peace negotiation was attended by both Chiang Kai-shek and Mao Zedong in Chongqing from 28 August 1945, and concluded on 10 October 1945 with the signing of the Double Tenth Agreement. Both sides stressed the importance of a peaceful reconstruction, but the conference did not produce any concrete results. However, large campaigns and full-scale confrontations between the communists and Chiang's troops were temporarily avoided.
The territory controlled by the Chinese Communists in 1945 comprised a quarter of China's surface and a third of the population. The Kuomintang troops were superior in number and armament to those of the Communists. However, despite the disadvantage in military hardware, the Communists relied on their land reform policy. They continued to make the irresistible promise in the countryside to the massive number of landless and starving peasants that by fighting for them, they would be given their own land to grow crops once the victory was won. This strategy enabled the communist to access an almost unlimited supply of manpower for both combat and logistical purposes.
The truce fell apart on 26 July 1946, when Chiang Kai-shek launched a large-scale assault on Communist territory in North China. Knowing their disadvantages in manpower and equipment, the communists executed a "passive defense" strategy. It avoided the strong points of the Kuomintang army and was prepared to abandon territory in order to preserve its forces. The communists also attempted to wear out the Kuomintang forces as much as possible. This tactic seemed to be successful; after a year, the power balance became more favorable to the communists.
In March 1947 the Kuomintang achieved a symbolic victory by seizing the communist’s capital of Yan'an. The Communists counterattacked soon afterwards; on 30 June 1947 their troops crossed the Yellow River and moved to the Dabie Mountains area.
During the Liaoshen campaign, between September to November 1948, the Nationalist forces suffered sweeping defeats across northeast China, losing major cities of Jinzhou, Changchun and Shenyang in the process, eventually leading to the capture of Manchuria by the Communist forces.
The New 1st Army, regarded as the best Kuomintang army, was forced to surrender after the communists conducted a six-month siege of Changchun. The capture of large Kuomintang units provided the communists with the tanks, heavy artillery and other combined-arms assets needed to execute offensive operations south of the Great Wall. By April 1948 the city of Luoyang fell, cutting the Nationalist army off from Xi'an.
During the Huaihai Campaign, between November to January 1949, the communists secured east-central China, and reached Yangtze river. Between late November and late January 1949 was the Pingjin campaign, which marked the end of Nationalist dominance in the North China Plain. Tianjin was conquered by communist troops on 15th of January, and Beijing fell on 31st of January 1949.
After achieving decisive victory in Liaoshen, Huaihai and Pingjin campaigns, the communists wiped out 144 regular and 29 irregular Kuomintang divisions, which significantly reduced the strength of Nationalist forces. Stalin initially favored a coalition government in postwar China, and tried to persuade Mao to stop the communists from crossing the Yangtze and attacking the Kuomintang positions south of the river.
Mao rejected Stalin's position and on 21 April, began the Yangtze River Crossing Campaign. On 23 April they captured the Kuomintang's capital, Nanjing. By the end of May, Nanchang, Wuchang, Hanyang were all under the control of the Communists. The city center of Shanghai fell to the Communists on 27 May.
The Kuomintang government retreated to Guangzhou until October 15, Chongqing until November 25, and then Chengdu before retreating to Taiwan on December 10. By late 1949 the People's Liberation Army was pursuing remnants of Kuomintang forces southwards in southern China, and only Tibet was left.
On October 1, 1949, Mao Zedong officially proclaimed the founding of the People's Republic of China at Tiananmen Square. Chiang Kai-shek, 600,000 Nationalist troops, and about two million Nationalist-sympathizer refugees retreated to the island of Taiwan. After that, resistance to the Communists on the mainland remained substantial but scattered, such as in the far south.
In December 1949 Chiang proclaimed Taipei, the temporary capital of the Republic, and continued to assert his government as the sole legitimate authority of all China, while the People's Republic of China government continued to call for the unification of all China. The last direct fighting between Nationalist and Communist forces ended with the Communist capture of Hainan Island in May 1950, though shelling and guerrilla raids continued for a number of years. In June 1950, the outbreak of the Korean War led the American government to place the United States Seventh Fleet in the Taiwan Strait to prevent either side from attacking the other.