HONG KONG » The famine that gripped China from 1958 to 1962 is widely judged to be the deadliest in recorded history, killing 20 million to 30 million people or more, and is one of the defining calamities of Mao Zedong’s rule. Ever since, the party has shrouded that disaster in censorship and euphemisms, seeking to maintain an aura of reverence around the founding leader of the Communist state.

But with the approach of celebrations of the 120th anniversary Mao’s birth on Dec. 26, some of his supporters and party polemicists are stepping beyond the longstanding official reticence about the famine to argue for their own, much milder version of the disaster and to assail historians who disagree. They deny that tens of millions died in the famine — it was at most a few million, some of them say — and they accuse scholars who support higher estimates of fanning anti-party sentiment.

"The big rumor that 30 million people starved to death in the three years of hardship," said a headline in September in The Global Times, an influential party-run tabloid. It accompanied a commentary by a mathematician, Sun Jingxian, who has won publicity for his claim that at most 2.5 million people died of "nutritional fatalities" during the Great Leap Forward. He argues that bigger estimates are an illusion based on flawed statistics.

Sun asserts that most of the apparent deaths were a mirage of chaotic statistics: people moved from villages and were presumed dead, because they failed to register in their new homes.

A new book, "Someone Must Finally Speak the Truth," has become a touchstone for supporters of Mao, who deny that the famine killed tens of millions. The author, Yang Songlin, a retired official, maintains that at most 4 million "abnormal fatalities" occurred during the famine. That was indeed a tragedy, he acknowledges, but one for which he mostly blames bad weather, not bad policies. He and other like-minded revisionists accuse rival researchers of inflating the magnitude of the famine to discredit Mao and the party.

"Some people think they have an opportunity, that as long as they can prove that tens of millions of people died in the Great Leap Forward, then the Communist Party, the ruling party, will never be able to clear itself," Yang said by telephone from his home in Zhengzhou, a city in central China.

The Great Leap Forward started in 1958, when the party leadership embraced Mao’s ambitions to rapidly industrialize China by mobilizing labor in a fervent campaign and merging farming cooperatives into vast — and, in theory, more productive — people’s communes.

The rush to build factories, communes and communal dining halls into models of miraculous Communist plenty began to falter as waste, inefficiency and misplaced fervor dragged down production. By 1959, food shortages began to grip the countryside, magnified by the amount of grain that peasants were forced to hand over to the state to feed swelling cities, and starvation spread.

Officials who voiced doubts were purged, creating an atmosphere of fearful conformism that ensured the policies continued until mounting catastrophe finally forced Mao to abandon them.

Beginning in the early 1980s, restrictions on studying the famine began to ease. Historians gained limited access to archives, and sets of census and other population data gradually became available, allowing researchers to build a more detailed, albeit still incomplete, understanding of what happened.

Some scholars have concluded that about 17 million people died, while other counts go as high as 45 million, reflecting varied assumptions about the death rate in normal times as well as other uncertainties, including how much official statistics undercounted deaths during the famine years.

"Scholars disagree, but whether their estimate is somewhat higher or lower, that doesn’t affect the fact that the Great Leap Forward created a massive disaster," Lin Yunhui, a retired party historian at the National Defense University in Beijing who has spent much of his career studying Mao’s time, said by telephone. "My own estimate is that there were about 30 million abnormal deaths."

Few if any mainstream historians place any credence in the revisionists’ claims, but they express alarm that the party, which in recent decades has tolerated more open research into the period, seems to be encouraging a retreat into deceptive orthodoxies.

"I’ve long been maligned and attacked for my research, but now there are these people who basically deny that there was ever a mass famine," Yang Jisheng, 72, a historian and former Xinhua News Agency journalist in Beijing who has been the main target of the attacks, said by telephone. He is not related to Yang Songlin.

"Tombstone," Yang Jisheng’s landmark study of the Great Leap famine — published in Chinese in Hong Kong in 2008 and in a modified, abridged English-language edition in 2012 — is banned in mainland China but has been read widely there through smuggled and bootlegged copies.

Yang Jisheng estimates that 36 million people died because of brutality and food shortages caused by the Great Leap Forward. He called the denials of widespread famine more than half a century ago a disturbing symptom of present-day political anxieties.

"To defend the ruling status of the Communist Party, they must deny that tens of millions died of starvation," Yang Jisheng said. "There’s a sense of social crisis in the party leadership, and protecting its status has become more urgent, and so it’s become even more necessary to avoid confronting the truth about the past."

China’s leaders have not publicly commented on the controversy. But Mao’s reputation remains important for a party that continues to stake its claims to power on its revolutionary origins, even as it has cast aside the remnants of his revolutionary policies. And paradoxically, Xi Jinping, the party leader installed in November, has been especially avid in defending that legacy, even though his family suffered more under Mao than his recent predecessors did.

Xi is the son of Xi Zhongxun, a colleague of Mao who was purged in 1962 and endured 16 years of imprisonment and political ignominy. Xi’s handling of the past, however, is driven by political imperatives, not family memories, said Edward Friedman, an emeritus professor of political science at the University of Wisconsin-Madison who was an editor of the English version of Yang Jisheng’s book "Tombstone."

Xi told officials in January that they should not belittle or doubt Mao’s achievements. He has repeatedly cited the collapse of the Soviet Union as a warning of the costs of political laxity. He approved a directive issued in April that identified seven main ideological threats to party rule, including "historical nihilism" — defined as attempts to "negate the legitimacy of the long-term rule of the Chinese Communist Party" by maligning the party’s record.

"They need their great leader to be pure," said Friedman. "They need to have a vision of the past that’s worth being nostalgic about."

© 2013 The New York Times Company