In the early 1950's, Mao Zedong began the nationwide Suppression of Counter-Revolutionaries Movement. The Movement was aimed at eliminating remnants of the Republic of China government and the Kuomintang Party, as well as their secret agents and local armed forces. On February 21, 1951, in order to provide a legal basis for the Anti-Revolutionary Movement, the Central People's Government promulgated the People's Republic of China Regulations on Punishing Counter-Revolutionaries. Those Regulations stipulated the following:

"If there is any collusion with imperialism; instigation; seduction; bribing of public officials; rebellion by armed forces or militias; armed rebellion; participation in spying or espionage organizations; assembly or use of underground organizations for the purpose of counterrevolution; looting or destruction of public or private property or public facilities; poisoning or murdering; forging of official documents; inciting the masses to oppose the government or instigating anti-unity; fabricating or spreading rumors; sneaking across the border; breaking out of or escaping from prison; harboring or shielding counter-revolutionary criminals; or any successful or unsuccessful attempt at the aforementioned, such can be classified as a crime of counterrevolution."

In fact, as early as March of 1950, the Chinese Communist Party (CCP) Central Committee issued the Instructions on Suppressing Bandits and Establishing a New Revolutionary Order, and the Instructions on Suppressing Counter-Revolutionary Activities. However, the methods of suppression were still relatively loose at that time. With the outbreak of the Korean War in June of that year, Mao Zedong believed that before sending troops to "repel the foreigners", they would first need to "pacify the locals". On October 10th of the same year, the Instructions on Suppressing Counter-Revolutionary Movements (also known as the Double Ten Instructions) were issued to expand the scale of the repression. Four months later, the Regulations on Punishing Counter-Revolutionaries were officially promulgated.

The interpretation of crimes of counterrevolution and punishment standards in the Regulations on Punishing Counter-Revolutionaries were very general and ambiguous, which caused the Anti-Revolutionary Movement to greatly expand. As a result, a large number of unjust, false, and wrongful convictions occurred. According to official statistics in 1954, more than 2.6 million people were arrested, more than 1.3 million were imprisoned, and 712,000 were executed. However, Yang Kuisong, an expert on CCP history, has pointed out that, in late April 1951, Mao Zedong euphemistically criticized some localities for putting too much emphasis on "more killings" and thus "concealing reports". In other words, the actual number of victims may be more than what was reported at the time.

The Anti-Revolutionary Movement only began to wane in 1953. During this period, the Land Reform Movement and the Korean War were also being carried out. Both Mao Zedong and Liu Shaoqi said that the Korean War provided opportunities for them. Historical evaluation of the Anti-Revolutionary movement has been mixed. Officials and some scholars believe that this move to eliminate hostile forces laid the foundation for China's subsequent development; however, some people consider the Anti-Revolutionary Movement to be the first major heinous crime committed by the Communist Party. Scholar Yang Jisheng has stated that, after the founding of the PRC, the saying that "class warfare is easy and effective" led to continuous repression. This repression gradually expanded to become more and more serious, and, after a long-term build-up, it finally exploded into the Cultural Revolution.

References: Taiwan People News (https://www.peoplenews.tw/news/fcac4230-0baa-473b-b657-46a9102f6b8a); Voice of America (https://www.voachinese.com/a/article-20110627-how-many-people-were-killed-during-the-crackdown-of-the-counterrevolutionaries-124605564/783702.html); "The World Turned Upside Down: A History of the Chinese Cultural Revolution"; Wikipedia (https://zh.wikipedia.org/wiki/镇压反革命运动)