Second Kuomintang-Communist Civil War

The Second Kuomintang-Communist Civil War, called the National Protection War against the Communist Rebellion or Mobilization for the Suppression of Communist Rebellion by the Kuomintang (KMT), and Chinese People's War of Liberation or simply, War of Liberation, by the Chinese Communist Party (CCP), was a conflict between the KMT and the CCP for the leadership of China. It was the second stage of the Chinese Civil War. The result of the civil war was that the CCP became victorious, leading to the retreat of the government of Republic of China to Taiwan, the proclamation of the People's Republic of China, and the two regimes between the mainland and Taiwan each declaring itself as the legitimate Chinese government at present.

Background
On August 15, 1945, the Empire of Japan, the common enemy of the Kuomintang and the CCP, announced its surrender, which marked the end of the Second Sino-Japanese War. The surrender of Japan intensified the rivalry between the KMT and the CCP which was previously weakened by the ongoing war against it.

On the eve of Japan's surrender, the major force of the KMT's army was concentrated in the home front, with almost no regular army present north of the Yangtze River and east of the Pinghan Road. The only army located to the South of the Yangtze River and to the east of the Guangzhou–Hankou railway and only troops from the Third War Area south of the Yangtze River and east of the Guangdong-Hankou Railway were the troops from the third military region.

By April 1945, the CCP along with the Eighth Route Army which was under its leadership had controlled most of the rural areas of northern China, with a total population of around 95.5 million. The CCP had also built up an army that could compete with the KMT. Socially, due to the devastation brought about by the Second Sino-Japanese War, the gentry, which used to be a group that could help stabilize the society, was disintegrated. As a result, the social instability led to an increasing number of the unemployed population, many of some became the supporters of the CCP. So, the size of the People's Liberation Army, the principle military force of the CCP, experienced a rapid expansion.

According to the Sino-Soviet Treaty of Friendship and Alliance, the Nationalist Government had the legal status over northeastern China. The Article 5(b) of the treaty stipulated no restriction on the movement be imposed on the government troops from moving into or within northeastern China. In addition, Article 2 stipulated that military mobilization within the territory of China (except for the Northeast) should cease. However, the CCP believed it also had the right to take over the Northeast and refused to comply with this treaty. It continued to deploy troops from the China proper to the Northeast to take over the Soviet troops who were occupying it at the time.

Surrender and takeover
On August 15, the Japanese Emperor announced the surrender of the Empire of Japan. The CCP-controlled Eighth Route Army and New Fourth Army refused Chiang's order to wait the government forces to arrive and receive Japanese surrender, as stipulated in the Sino-Soviet Treaty of Friendship and Alliance. Instead, they launched an offensive on all fronts against the Japanese and collaborationists. In addition, the CCP ordered the Japanese to surrender to the Eighth Route Army and the New Fourth Army unless they were encircled by the government forces. On August 16, Mao Zedong, the chairman of the CCP, published the article "People's Enemy Chiang Kai-shek Sends Out a Signal for Civil War" in the CCP-owned Xinhua News Agency. In the article, Mao falsified the remarks made by Wu Kuo-chen, the Undersecretary of the Ministry of Foreign Affairs of the government by slandering that Wu accused Chiang Kai-shek of "sending out a signal of civil war" by intending to deal with the opponents "with military justice". in fact, Mao was deliberately breaking with the KMT and preparing to launch a civil war to topple the government in the name of opposing the civil war.

Early negotiations
On August 14, 1945, Chiang Kai-Shek invited Mao Zedong to go to Chongqing, the wartime capital of China, to negotiate with each other and reduce the disagreements between the KMT and the CCP. On August 24, Mao agreed under the order made by Joseph Stalin in the name of the Central Committee of the Communist Party of the Soviet Union. After the negotiation, an agreement was reached on October 10. One of the few key policies reached in the agreement stipulated that the CCP recognize the Nationalist government as the sole legitimate Chinese government while the KMT recognize the CCP as a legal opposition party. In addition, the agreement scheduled a future meeting between the major political factions in China to discuss unsolved problems.