Death of Mao Zedong and Arrest of the Gang of Four
Also called: Gang of Four, Death of Mao Zedong, Huairen Hall coup
Mao Zedong died on 9 September 1976, and a month later, on 6 October, Hua Guofeng, with Ye Jianying and Wang Dongxing, arrested the “Gang of Four” — Jiang Qing, Zhang Chunqiao, Yao Wenyuan and Wang Hongwen. The Cultural Revolution was effectively over.

Karl-Heinz Wellmann · CC BY-SA 4.0 · Source
Mao died in Beijing at ten minutes past midnight on 9 September 1976, aged 82. A power struggle at once broke out between Hua Guofeng, Mao’s chosen successor, and the leaders of the Cultural Revolution — Jiang Qing, Zhang Chunqiao, Yao Wenyuan and Wang Hongwen. On the evening of 6 October Hua, together with the veteran marshal Ye Jianying and Wang Dongxing, who controlled the Central Guard Unit, summoned the four to Zhongnanhai on the pretext of a meeting and had them arrested; the next day Hua became party chairman. The official account later held that Mao himself had warned them against acting as a “gang of four”.
News of the arrests set off celebratory marches in Beijing and across the country. The Eleventh Party Congress of August 1977 declared the Cultural Revolution over, and Deng Xiaoping, rehabilitated once more, took effective control at the Third Plenum of December 1978 and set China on the path of reform and opening up. The Gang of Four were tried in public with the Lin Biao group from November 1980; in January 1981 Jiang Qing and Zhang Chunqiao were sentenced to death with reprieve (later commuted to life), Wang Hongwen to life and Yao Wenyuan to twenty years.