Gang of Four
The four radical leaders, led by Mao's last wife Jiang Qing, who drove the Cultural Revolution's fanatical phase and were scapegoated for it.

When Mao Zedong died on September 9, 1976, four people held the levers of China's propaganda, culture, and much of its ideology, and they expected to inherit the country. Twenty-seven days later they were under arrest. The Gang of Four, Jiang Qing (Mao's fourth and last wife), Zhang Chunqiao, Yao Wenyuan, and Wang Hongwen, had spent a decade as the sharpest edge of the Cultural Revolution. Then, almost overnight, they became the people the Communist Party would blame for the whole catastrophe, so that Mao himself would not have to be.
Four radicals from Shanghai
The four were bound together by the city of Shanghai and by a shared appetite for permanent revolution. Yao Wenyuan was a literary hatchet man whose 1965 essay attacking a historical play helped light the fuse of the Cultural Revolution. Zhang Chunqiao was the group's cold theorist. Wang Hongwen, a former textile-mill security officer, rose from factory-floor rebel to national vice-chairman in a few dizzying years. Jiang Qing, a former actress, seized control of the arts, permitting a handful of approved 'model operas' while condemning most of China's cultural inheritance as feudal poison.
Their weapon was the accusation. To be named a 'capitalist roader' or a class enemy could mean the end of a career, a beating by Red Guards, prison, or death. They purged officials, wrecked reputations, and kept the persecutions going long after much of the country had exhausted itself. Mao used them, protected them, and distrusted them; it was he who coined their nickname, warning Jiang Qing in 1974 and 1975 not to form a 'gang of four.'
The trap in Huairen Hall
Mao's death removed their shield. On the night of October 6, 1976, acting leader Hua Guofeng, military elder Ye Jianying, and security chief Wang Dongxing sprang a trap. Zhang Chunqiao, Wang Hongwen, and Yao Wenyuan were summoned one by one to Huairen Hall in the Zhongnanhai leadership compound and arrested as they arrived; Jiang Qing was seized at her home. No shots were fired. The arrests, secret at first, effectively ended the Cultural Revolution and cleared the road for Deng Xiaoping's return and the reforms that followed.
One dog, ten years of ruin
The trial, held in Beijing from November 1980 to January 1981, was theater with a purpose: the Party needed the decade's horrors to have a small number of authors. Jiang Qing was the only defendant who fought back, shouting that she had merely obeyed her husband. 'I was Chairman Mao's dog,' she said. 'I bit whomever he asked me to bite.' It was a devastating line precisely because it was half true, and it pointed at the one man no one could indict. She and Zhang Chunqiao drew suspended death sentences, later commuted to life; Jiang Qing killed herself in 1991. Convicting four people let the Party keep Mao, and with him its own legitimacy, largely intact.
Months later the official verdict called Mao seventy percent right and thirty percent wrong. Four defendants in one Beijing courtroom had been made to carry most of the thirty.