Beijing: The eulogies for magazine Yanhuang Chunqiu, arguably China's last torchbearer of liberal thought and critique, are already being written: the monthly journal's senior figures have been sidelined in a hostile purge, its offices effectively taken over by authorities.

The journal's credibility and significance have long stemmed from the liberal, reform-minded party elders who backed it, and its regular pushing of the boundaries with its forthright, unsanitised essays which contest official Communist Party versions of history, such as the events of the Cultural Revolution.

It has survived numerous scrapes with Chinese authorities and come under pressure to soften its editorial line. But after 25 years in print, the magazine announced this month it had suspended publication, another victim of Chinese President Xi Jinping's campaign to tighten ideological control within the party and the country's state-controlled media.

On Tuesday, Hu Dehua, the magazine's deputy publisher and the son of the late reformist Communist Party leader and liberal icon Hu Yaobang, pushed back at the journal's enforced closure in a calculated gambit; a last stand not just for the magazine, but potentially for the rapidly shrinking voice of the Communist Party's more liberal elements as a whole.

With a clutch of unidentified, plain-clothed men blocking the entrance to the magazine's Beijing offices, Mr Hu instead held an impromptu press conference outside for a handful of reporters from overseas media outlets.

"I don't know who these people are," Mr Hu said, referring to the plain-clothed men who by now were filming his every word and move. "There are more bad people out there these days, and more hooligans. I ask them who they are, they don't tell me their names, or their work unit, maybe they're bad guys.

"You can't just take over the offices because you say so. In China we have a saying, 'even rabbits bite when they're provoked'."

In China, publishers are required to have a government department sponsor as oversight. In Yanhuang Chunqiu's case, it is the Chinese National Academy of Arts, an organisation under the umbrella of the Ministry of Culture.

In an abrupt statement on July 12, the academy said it had removed the journal's 93-year-old publisher and co-founder Du Daozheng, saying he was "getting on in years". It later cited a rule against party officials taking up positions after they reach 70 years of age. It installed its own replacement publisher, deputy publishers and demoted the magazine's editor-in-chief, Xu Qingquan.

The plain-clothed men occupying the office, Mr Hu said, were also impeding staff from preparing and lodging company taxes, a move he implied was designed to enable the authorities to manufacture further infringements against the publishing house.

Mr Hu cited an official agreement reached with the academy in 2014 which guaranteed Yanhuang Chunqiu editorial independence and the right to appoint managers and editors, in return for promising not to encroach on overtly politically sensitive topics, including high-level corruption. The magazine's lawyers have filed a lawsuit through the courts in an attempt to regain control, but the case has been rejected. He said the move against the magazine was too "crude" to have been endorsed by the most senior levels of Communist Party leadership.

"President Xi has consistently emphasised the rule of law, you have to do everything by the law," Mr Hu said. "This is a clear violation of a contract - if the court does not accept our case, it is a dereliction of duty."

Mr Hu and other liberals from prominent families have traditionally been afforded greater leeway to speak their mind by virtue of their family connections. But this has diminished considerably since the elevation of Mr Xi to the presidency in early 2013, with prominent figures explicitly warned to watch what they say, especially to the foreign press, while urging cadres to rally around the flag, stressing the importance of party discipline and unity.

"The broader environment is that the official ideology is becoming more and more 'red', media control is tightening," Wu Si, a former editor-in-chief at Yanhuang Chunqiu, told Fairfax Media. "Before the 18th Party Congress [which confirmed Mr Xi's ascent], there was very little discussion of party ideology, and conviction in socialism - now the tone is stronger and stronger."

Monash University historian Warren Sun says Yanhuang Chunqiu's fate was virtually sealed with the introduction of the so-called Document No. 9, which warned against growing Western influences including freedom of the press and "historical nihilism".

"Apparently Xi's tightening control of voices is not just confined to the present, but even extended to silence the past," Dr Sun told Fairfax Media. "Despite its liberal stand, the journal was able to survive and thrive under [Chinese presidents] Jiang Zemin and Hu Jintao for more than two decades.

"The likely closure of arguably the last truth-speaking platform only attests to the sad fact that ideological controls under Xi have produced the most depressing political climate in post-Mao China."

with Sanghee Liu