Zhang Hongbing's family photos and pictures of his mother. The bottom photo is an original copy of a photo from which other copies had her image torn out. Photograph: Dan Chung for the Guardian
She met her husband when they joined the revolutionary cause, but their life was scarred by politics from the first. Her father was executed as a suspected Nationalist agent; Zhang blames a personal grudge. Later, as they struggled to survive the Great Famine, Zhang's younger brother was sent away to a relative who could feed him.
Then the Cultural Revolution burst into their lives. In the streets of Guzhen, Red Guards smashed heirlooms and burned books: "I thought it was great – an unprecedented moment in history," Zhang said.
In a blaze of enthusiasm, the children changed their names. Zhang, previously called Tiefu, became Hongbing, or "red soldier". His elder sister joined millions of Red Guards trekking to Beijing to see Mao. But shortly after her return, she collapsed and died from meningitis, aged 16. Months later, their father was attacked as a "capitalist roader" in at least 18 "struggle sessions" of verbal and physical abuse.
"I wrote a big character poster about him; I just wanted to follow Chairman Mao," said Zhang. "For a child to criticise their parents wasn't just our household. The whole country was doing it."
In 1968, Fang fell under suspicion due to her father. Two years of investigation, detention and uncertainty tormented her: "Why don't they just make a decision on me?" she asked.
"Her father's death, her husband's persecution, her daughter's death – everything that happened made her suspicious of the Cultural Revolution … She was sick of [it]," said Zhang.
Eventually conditions improved and she was allowed to sleep at home. Then, one evening, her zealous son accused her of tacitly criticising Mao. The family row spiralled rapidly: Fang called for the return of purged leaders and attacked Mao for his personality cult. "I warned her: 'If you go against our dear Chairman Mao I will smash your dog head,'" Zhang said, at times reading from his father's testimony. "I felt this wasn't my mother. This wasn't a person. She suddenly became a monster … She had become a class enemy and opened her bloody mouth."
Fang's brother begged her to take her words back, warning she would be killed. "I'm not scared," Fang replied. She tore down and burned Mao's picture.
When her husband and son ran to denounce her, "I understood it meant death," Zhang said. In fact, he added, he called for her to be shot as a counter-revolutionary. He last saw her as she knelt on stage in the hours before her death.Most children who turned on their parents were under political pressure, said Yin Hongbiao, a Beijing-based historian.
"Those with 'bad parents' suffered a lot and they resented their parents instead of resenting the system which brainwashed them daily," added Michel Bonnin, of Tsinghua University.
"They were encouraged to denounce their parents, so as to 'draw a line' between them and the enemy. It was the only way to save themselves. There were many cases of children who tried to protect their parents against the violence of Red Guards and were then beaten or even executed."
Zhang's case is much more unusual, but Schoenhals suggested timing was critical: early 1970 saw a harsh campaign against counter-revolutionary activities, known as one-strike and three-anti. "You could come across anything if you had 700 million people embroiled in a conflict of this seriousness and magnitude," he added.
Fang Meikai, though furious with his sister's family, was powerless to help her. "I wanted to see her, but I wouldn't have been allowed. I was afraid that if I went I would also be involved in the case," he said. "That was the situation back then: they could kill whomever they wanted."