“So Mao and his [Chinese] KGB chief Kang Sheng devised a blanket accusation—that the vast majority of Communist organizations in the Nationalist areas were spy rings working for Chiang Kai-shek….
“By deploying this charge, Mao found a way to place all the young volunteers in Yenan in one form of confinement or another for ‘screening,’ starting in April 1943. Thousands were arrested and thrown into prison-caves newly carved out of the loess hillsides. In one prison alone, in the ravine behind the Date Garden—the site of the Chinese KGB, where Mao also lived—cells were dug for over 3,000 prisoners.
“Turning ordinary organizations into virtual prisons was a significant innovation of Mao’s, which he was to apply throughout his rule. Here he went far beyond anything either Hitler or Stalin achieved: he converted people’s colleagues into their jailers, with former colleagues, prisoners and jailers living in the same premises…. In this way, Mao not only drove a massive wedge between people working and living side by side, he greatly enlarged the number of people directly involved in repression, including torture, making the orbit significantly wider than either Stalin or Hitler, who mostly used secret elites…that held their victims in separate and unseen locales.”
—Jung Chang and Jon Halliday, Mao: The Unknown Story