On May 7, 1966, during an expanded meeting of the Chinese Communist Party (CCP) Central Committee Politburo, Mao Zedong read the "Report on Further Improving the Army’s Agricultural Work by the Rear Service Department of the Military Commission" from the People's Liberation Army's General Logistics Department. The report affirmed that the military's agricultural production had important political and economic significance; not only could it increase grain output, but through it, the military could also carry out a certain degree of political education and military training. Mao Zedong was very satisfied after reading this; he wrote a letter to Lin Biao, in which he described the "new world" he had in mind. This letter came to be called the "May 7 Instructions". An excerpt from these "Instructions" follows:

"So long as there is no world war, the army should be a big school… This big school needs to provide studies in politics, military affairs, and culture. It should also be able to engage in agricultural and sideline production, as well as to run some small factories to produce some of its own products that are needed and products that can be exchanged with the state at an equivalent value. They can also engage in mass work and participate in the Four Cleanups Movement for social education in factories and rural areas; once compulsory education for the socialist movement is done, there always remains mass work to be done, to forever unite the army with the people. The army should also always participate in the cultural revolutionary struggle to criticize the bourgeoisie…"

On May 15, 1966, the CCP Central Committee forwarded the "May 7th Directives" to the whole party, requesting that the entire Party implement them in a step-by-step way. The "People's Daily" newspaper also published an editorial, saying that the May 7th Directives would "greatly raise the proletarian consciousness of the entire nation."

In May 1968, on the second anniversary of the "May 7th Directives", the Revolutionary Committee of Heilongjiang Province opened a farm in Liuhe Town, Qing'an County. To this farm were sent a large number of provincial government officials (cadres) and "capitalist roaders". The farm was named the May Seventh Cadre School. "People's Daily" promoted it vigorously, and published Mao Zedong's instructions: "The majority of cadres should be devolved to do labor work. This is an excellent opportunity for cadre re-education. Everyone should be involved in doing this, except for the elderly, the weak, the sick, and the disabled; presently-serving cadres should also be delegated to do such labor." From that point on, many places competed to copy this May Seventh Cadre School.

The May 7 Cadre Schools were generally located in remote and poor rural areas. The "cadets", regardless of age and gender, were all assigned to companies, platoons, and squads, modeled on military organization. All were required to live militarized lives. As they went into the fields and when they came back, they were required to chant slogans and sing songs based on the Little Red Book (quotations from Mao). What they learned was how to do manual labor. Compared with the brutal struggles and "criticism sessions" of the Cultural Revolution, life in the May 7 Cadre Schools was an escape for some. However, under control by this ultra-leftist ideology, many May 7 Cadre Schools turned into venues for persecuting cadres and punishing intellectuals; examples of campaigns that took place at the May 7 Cadre Schools include the Campaign to Root Out May Sixteenth Anti-Revolutionary Clique Elements (which aimed to eliminate forces in the Cultural Revolution deemed excessively leftist).

On February 17, 1979, the State Council issued the "Notice Regarding Suspension of May 7th Cadre Schools and Related Issues"; after this, May 7th Cadre Schools places were closed down, one after another.

References: Yang Jisheng, "The World Turned Upside Down: A History of the Chinese Cultural Revolution"; "History of the People's Republic of China: Smashing the Old World — Turmoil and Catastrophe in the Cultural Revolution (1966-1968)"; Frank Dikötter, "The Cultural Revolution: A People's History, 1962–1976"; [紐約時報中文網("New York Times Chinese Edition")(Chinese)] (https://cn.nytimes.com/china/20161228/may-7-cadre-schools/zh-hant/); [濟南文史網("Jinan Literary History Net")(Chinese)] (https://web.archive.org/web/20121128030219/http://www.jnzx.gov.cn:8080/Html/63702006926132144-1.Html); [維基百科("Wikipedia")(Chinese)] (https://zh.wikipedia.org/wiki/五七干校)