The Chinese Civil War was fought between the government of the Republic of China (ROC), led by the Kuomintang (KMT), and the Chinese Communist Party (CCP). Armed conflict continued intermittently from 1 August 1927 until Communist victory that led to the Kuomintang's retreat to Taiwan on 7 December 1949.
The war is generally divided into two phases with an interlude. In 1926 and 1927, the KMT and the CCP, allied with one another in the First United Front, had carried out a very successful campaign, the Northern Expedition, against warlords in central China. The CCP calls this the First Revolutionary Civil War. The united front broke up and war broke out between the KMT and the CCP on 1 August 1927. The CCP calls this the Second Revolutionary Civil War; it lasted until 1937. From 1937 to 1945, hostilities were mostly put on hold as the Second United Front fought the Japanese invasion of China with eventual help from the Allies of World War II. However, armed clashes between the groups remained common.
The civil war resumed as soon as it became apparent that Japanese defeat was imminent, with the communists gaining the upper hand in the second phase of the war from 1945 to 1949, generally referred to as the Chinese Communist Revolution. The CCP calls this the Third Revolutionary Civil War. The Communists gained control of mainland China and proclaimed the People's Republic of China (PRC) in October 1949, while the Republic of China government retreated to the island of Taiwan in December. Starting in the 1950s, a lasting political and military stand-off between the two sides of the Taiwan Strait has ensued, with the ROC in Taiwan and the PRC on the mainland both claiming to be the legitimate government of all China. In addition, ROC guerrilla forces continued to operate in mainland China and northern Burma until 1961. After the Second Taiwan Strait Crisis, both tacitly ceased to engage in open conflict in 1979; however, no armistice or peace treaty has ever been signed.
Following the collapse of the Qing dynasty and the 1911 Revolution, Sun Yat-sen assumed the presidency of the newly formed Republic of China (ROC), and was shortly thereafter succeeded by Yuan Shikai. Yuan failed in a short-lived attempt to declare himself emperor, and China fell into power struggle after his death in 1916.
The Kuomintang (KMT), led by Sun Yat-sen, created a new government in Guangzhou to rival the warlords who ruled over large swathes of China and prevented the formation of a solid central government. After Sun's efforts to obtain aid from Western countries were ignored, he turned to the Soviet Union. In 1923, Sun and Soviet representative Adolph Joffe in Shanghai pledged Soviet assistance to China's unification in the Sun–Joffe Manifesto, a declaration of cooperation among the Communist International (Comintern), KMT, and the Chinese Communist Party (CCP).
The CCP, which was initially a study group by Chinese intellectuals, was officially established in 1921 at the First National Congress in the French Concession in Shanghai, and the KMT jointly formed the First United Front, with the primary goal of defeating regional warlords, unifying China as well as sought to expel Western and Japanese imperialist powers who held control over Chinese ports and territories following the unequal treaties imposed after the Opium Wars, the First Sino-Japanese War and the Asian theater of World War I. Comintern agent Mikhail Borodin arrived in 1923 to aid in the reorganization and consolidation of both the Chinese Communist Party and the Kuomintang along the lines of the Communist Party of the Soviet Union.
In 1923, Sun sent Chiang Kai-shek, one of his lieutenants, for several months of military and political study in Moscow. Chiang then became the head of the Whampoa Military Academy that trained the next generation of military leaders. The Soviets provided the academy with teaching material, organization, and equipment, including munitions. They also provided education in many of the techniques for mass mobilization. With this aid, Sun raised a dedicated "army of the party", with which he hoped to defeat the warlords militarily. CCP members were also present in the academy, and many of them became instructors, including future communist premier Zhou Enlai, who was made a political instructor.
Communist members were allowed to join the KMT on an individual basis. The CCP itself was still small at the time, having a membership of 300 in 1922 and only 1,500 by 1925. As of 1923, the KMT had 50,000 members. However, after Sun died in 1925, the KMT split into left- and right-wing movements. Right-wing KMT members began to worry that the Soviets were trying to destroy the KMT from within using the CCP. In March 1926, Chiang Kai-shek, who had been made commander in chief of the KMT army, began the expulsion of communists from prominent positions, later known as the Canton Coup. The CCP then began movements in opposition of Chiang's leadership and the Northern Expedition, passing a resolution against it at a party meeting. Then, in March 1927, the KMT held its second party meeting where the Soviets helped pass resolutions against the Expedition and curbing Chiang's power. Soon, the KMT would be clearly divided.
In early 1927, the KMT–CCP rivalry led to a split in the revolutionary ranks. The CCP and the left wing of the KMT decided to move the seat of the KMT government from Guangzhou to Wuhan, where communist influence was strong. However, Chiang and Li Zongren, whose armies defeated the warlord Sun Chuanfang, moved eastward toward Jiangxi. The leftists rejected Chiang's demand to eliminate Communist influence within the KMT, and Chiang denounced them for betraying Sun Yat-sen's Three Principles of the People by taking orders from the Soviet Union. According to Mao Zedong, Chiang's tolerance of the CCP within the KMT camp decreased as his power increased.
On 7 April, Chiang and several other KMT leaders held a meeting, during which they proposed that Communist activities were socially and economically disruptive and had to be undone for the Nationalist revolution to proceed. On 12 April, many communists within the KMT were purged in Shanghai through hundreds of arrests and executions on the orders of General Bai Chongxi. The CCP referred to this as the 12 April Incident, known in the West as the Shanghai massacre, and the beginning of the White Terror. This incident widened the rift between Chiang and Wang Jingwei, the leader of the left wing faction of the KMT.
Under pressure from Chiang, the left wing of the KMT also began expelling CCP members from the Wuhan Government in July 1927, which in turn was toppled by Chiang Kai-shek. The KMT resumed its campaign against the warlords and captured Beijing in June 1928. Soon, most of eastern China was under the control of the Nanjing central government, which received prompt international recognition as the sole legitimate government of China. The KMT government announced, in conformity with Sun Yat-sen, the formula for the three stages of revolution: military unification, political tutelage, and constitutional democracy.
On 1 August 1927, the CCP launched an uprising in Nanchang against the Nationalist government in Wuhan in response to the Shanghai Massacre. This conflict led to the creation of the Chinese Red Army. On 4 August, the main forces of the Red Army left Nanchang and headed southwards for an assault on Guangdong. Nationalist forces quickly reoccupied Nanchang while the remaining members of the CCP in Nanchang went into hiding. A CCP meeting on 7 August confirmed the objective of the party was to seize political power by force, but the CCP was quickly suppressed the next day by the Nationalist government in Wuhan, led by Wang Jingwei. On 14 August, Chiang Kai-shek announced his temporary retirement, as the Wuhan faction and Nanjing faction of the Kuomintang were allied once again with common goal of suppressing the CCP after the earlier split. Wang Jingwei took the leadership of KMT after Chiang.