When the Tiananmen students' movement was taking place 24 years ago, Du Bin was a junior secondary school student in Linyi , Shandong , and knew little of what was happening. When he joined the army later, he was posted to a unit that had taken part in the crackdown. But no one talked about it.
It was only in 2004 that Du, having scaled the internet firewall, first encountered this piece of history.
Two weeks ago, a book he edited, The Tiananmen Massacre, was published in Hong Kong.
This must be the first time a Chinese person had edited a book on June 4 while living on the mainland. I asked him why he did it. He said he wanted to exercise his own right to know, first and foremost; he couldn't let that part of history remain a blank.
Yet for those with experience of June 4, that part of history has ever since been a blank. After sending in the tanks and troops to suppress the pro-democracy movement, the Chinese Communist Party made June 4 the most taboo of sensitive subjects. In 1990, writer Liao Yiwu was sentenced to jail for four years for writing a poem titled Massacre. Openly writing about June 4 became a dangerous act.
But it didn't stop people writing about it privately or obliquely. Those who took part in the protest and are now exiled overseas have posted their accounts online. On the mainland, people remember June 4 or protest against the censorship through poetry and metaphors.
On the 18th anniversary of the crackdown, in 2007, the Chengdu Evening Post ran an advertisement "saluting the tough mothers of the June 4 victims". That was the work of human rights activist Chen Yunfei, who, realising classified ads were not as tightly monitored, slipped the message past the censors. Some say the young woman responsible for vetting the ads even called a friend to ask what had happened on June 4 that had resulted in people getting hurt. "Probably another mining disaster," was the answer she got. This is one result of trying to banish June 4 from our collective memory.
By 2009, veiled references to the event - "May 35", "8 x 8" - were all over the internet. Writer Ye Fu posted his own account of the event, even naming informers.
Successful censorship depends on co-operation between those who gave the order and those who received it. If people accept the ban, it would be effective; if they do not, it would not work, for the truth will out.
Take the strict prohibition on talk about Tibet. It is generally accepted, so the ban has been effective. By contrast, the people have refused to be silenced over Tiananmen, and they keep trying to find ways to speak up.
To borrow a theory from the study of art and literature, the audience's participation is critical here: a ban becomes meaningful only when those at which it is targeted experience it as meaningful.
When Xi Jinping came to power, many people pinned their hopes on him to reverse the damning verdict on the Tiananmen movement. It seems unlikely now that the leadership will do so voluntarily. But the people's insistence on speaking the truth may one day bring down the house of cards. The further Tiananmen recedes into history, distancing current leaders from the responsibility and blame for the tragic crackdown, the more likely it will be for Beijing to ease the June 4 gag, as a way of scoring some easy popularity points.
It's been days since The Tiananmen Massacre went on sale, and Du Bin has so far been spared too much police harassment.
However, people who believe that simply telling the truth about June 4 would serve to topple the Communist Party should think again. The reverse could well happen: with the ban lifted, some people would start telling their stories, but more people could start defending the government's actions.
Something similar has already happened. When I was in Hong Kong in 2009 for a study trip to the University of Hong Kong, I saw how Hong Kong and mainland students were divided over June 4.
The mainland students who learned the facts of June 4 only after they arrived here did not react angrily to having been deceived. Instead, their identity has become so intertwined with the Communist Party's that when Hong Kong students denounced the violence of the communist government, the mainland students felt it as a personal attack.
These mainland students believed what they were taught post 1989: that government repression was necessary to China's economic development, so that for the prosperity and good life that many Chinese now enjoy, the price of some freedom and rights is small indeed.
Open public debate is important. But whereas the fight has been to escape the gag order, now the right to speak must be used to counter misinformation about June 4.
Chang Ping is a current affairs commentator writing on politics, society and culture. This commentary is translated from the Chinese article