Fifty-seven years ago today, on May 25, 1968 (April 29, 1968), the whole country launched a campaign to "clean up the ranks of the classes". On May 25, 1968, the Central Committee of the Communist Party of China and the Central Cultural Revolution Group issued the "Notice of Forwarding Chairperson Mao's Instructions on the" Experience of the Military Control Committee of Beijing Xinhua Printing Factory in Mobilizing the Masses to Launch a Struggle against the Enemy ". On May 19, Mao Zedong issued an instruction on the" Experience of the Military Control Committee of Beijing Xinhua Printing Factory in Mobilizing the Masses to Launch a Struggle against the Enemy ". The instruction said:" Comrade Wen Yuan: It is recommended that this piece be wholesale throughout the country. Among the similar materials I have seen, this piece is the best written. "This material was submitted to Mao Zedong by Yao Wen Yao Wenyuan wrote in the submitted report: "This piece summarizes some policy issues in the cleanup team." The "Notice" requires all localities to learn from the experience of Xinhua Printing Factory in carrying out struggles against the enemy, and pay attention to summarizing the experience of the region. In the work of cleaning up the class ranks of teachers and staff in factories and mines, institutions and cultural and educational systems, conduct in-depth and meticulous investigation and research work, distinguish between two types of contradictions of different natures, and firmly and accurately attack a small number of class enemies. Since then, the whole country has carried out a "cleanup of class ranks" movement one after another. The main experience introduced by Xinhua Printing Factory is that in the 18 years since the founding of the People's Republic of China, the class struggle in this factory has been extremely sharp and fierce. After the military personnel entered the factory, they paid close attention to the class struggle and did not turn around, and let The specific measures are: for the broad revolutionary masses, we must firmly rely on them, and we must also be good at guiding them; for those who have made serious mistakes, we must strictly demand them, and we must also pay attention to the knot; for a small group of class enemies, we must severely attack them, and we must also divide and disintegrate them, and point out the way out. In the movement to clean up the class ranks, all localities adopted the methods of the Military Regulatory Commission and the garrison of the Industrial Propaganda Team, and carried out a large-scale inventory of the land, wealth, opposition, bad, right, secret services, traitors, capitalist roaders, leaking right, and the "remnants" of the Kuomintang that were pulled out in various names and in various ways during the process of the Cultural Revolution. Although at the beginning of the movement, the Central Committee of the Communist Party of China has emphasized "the need for in-depth and meticulous investigation and research work" to "distinguish between two types of contradictions of different natures", and despite the continuous instructions in the movement to "pay attention to policies and attack on the side of the side, the movement has still produced many unjust and false convictions.