CHINA’S infamous internet censorship machine may not work exactly as you imagine, a groundbreaking experiment has revealed.

The government has been controlling the country’s press for decades, but the enormous reach of the internet has forced it to become more sophisticated in how it operates.

With social media offering China’s 1.3 billion residents the opportunity to broadcast their views, the government has had to become more sophisticated when it comes to what it deletes and what it allows through.

Rather than banning all criticism of the government, censors allow many negative posts through, according to a study published in Science magazine.

It’s all about suppressing rebellion, the researchers reveal, with criticism of the state and its leaders allowed, but specific support for any oppositional party forbidden.

The government will even sometimes act on negative sentiment expressed towards particular politicians and remove them from office, making them scapegoat for problems.

The researchers were able to gain unprecedented access to the workings of Chinese censors by setting up their own social media network.

They were then given direct access to the censors’ software, documentation and customer service helpdesk, allowing them to “reverse-engineer how it all works”.

At the centre of the Communist state, tens of thousands of censors are sifting through posts, deciding what to take down, they learned.

Censors both “post-moderate” existing social media posts, as well as “pre-moderating” comments picked up by keyword filters before they are published.

“Criticisms of the state, its leaders, and their policies are routinely published, whereas posts with collective action potential are much more likely to be censored — regardless of whether they are for or against the state,” write the researchers.

Bloggers can be as vitriolic as they like about China’s top leaders, but any mention of an ongoing protest, or a rally in favour of a popular policy or leader, will be censored.

This happens even when the writer is criticising the rally.

Censorship is now used to muzzle any attempt to “spur the creation of crowds for any reason — in opposition to, in support of, or unrelated to the government.”

The work is fascinating in that it proves that dissent on the web is not only being censored, but “is used by Chinese leaders to determine which officials are not doing their job of mollifying the people and need to be replaced.”

Rather than being increasingly free to say what they want, China’s many critics are being used to create “actionable information” for the government, scholars and public policy analysts.

China has been restricting what its people get to hear since the third century BC, when Emperor Qin burned Confucian texts.

In 2008, USA Today reported that any Chinese person searching on words such as “persecution”, “Tibetan independence” or “democracy movement” would simply find a blank page.

While many Chinese “hackivists” work to fight the “Great Firewall of China”, they admit they have to move quickly because the censors are so smart.

The censors also use other tactics. They create bottlenecks by using a limited number of servers, issuing propaganda, getting help from the US and forcing webmasters to self-censor or be shut down.

China has been engaged in a long-running battle with Google, but in May it initiated a near complete block on the tech company’s products, ahead of the 25th anniversary of the 1989 Tiananmen Square protests.