It was on the morning of June 5 that he appeared from nowhere. A line of 18 tanks began to pull out of Tiananmen Square and drove east along the Avenue of Eternal Peace.

A day earlier, the square had been cleared of students. The provocative plaster Goddess of Democracy statue had tumbled under the tracks of a tank. After seven weeks, the Communist Party was again in control of the plaza that symbolises the heart of its power. The broad road was empty of humanity before the fearsome display of force.

Suddenly a slight figure in a white shirt and black trousers, a shopping bag in each hand, dashed out into the road and stood waiting as the tanks approached. The lead vehicle halted. It was a breathtaking standoff. The lone man stood firm. Would the tank run him down? It moved right to go around him. The man waved the shopping bag in his right hand then danced a few steps to the left to block the tank again. The tank swerved back left to avoid him. The man waved the bag again and stepped to the right. Both halted. The tank even turned off its engine.

Then the man switched his bags into one hand and jumped on to the machine. He banged his fist on the metal monster and appeared to talk to the soldiers inside. After a few moments he clambered back to the ground and resumed his blocking position. The tank driver even opened the hatch, perhaps to talk.

Then a man on a bicycle darted out from the roadside. Two others followed on foot, hands in the air, rushing to hustle the unknown man out of harm's way. He was never seen again.

The tanks trundled forward, mashing the asphalt under their tracks as they left the city. It has become an image for ever identified with the defiance displayed that spring by students and citizens demanding greater freedoms and more accountability from their Government.

The identity of Tank Man remains a mystery. Did he vanish back into the crowd? Was he picked up by police and jailed? Even executed? Throughout the deathdefying stand-off, none of the many cameras focused on him from the Beijing Hotel ever captured his face. Perhaps only the tank driver and passers-by who pulled him away ever saw his features.

The only official comment that China made came from the previous President, Jiang Zemin, in an interview in 1990 with Barbara Walters. Speaking through an interpreter, he said: "I can't confirm whether this young man you mentioned was arrested or not." Then he added in English: "I think never killed."

Within days of the incident, the Sunday Express named him as Wang Weilin, 19. That identification is now regarded as almost certainly spurious.

Even the aggressive media in Hong Kong and Taiwan have failed to track him down. One anonymous writer, identifying himself only as a Hong Kong academic, produced a detailed article saying that the man was an archaeologist who eventually found safety in Taiwan, where he worked for the National Palace Museum and had chosen to live in secrecy. The museum issued a clear denial. Other media found no trace of him on the island.

There have been detailed discussions about whether the men who helped him away were secret police or anxious bystanders, with debate based on complicated analysis of their clothes and demeanour.

The American broadcaster PBS devoted a 50-minute documentary to Tank Man in 2006. If it reached any conclusion, it was that he simply disappeared back into the anonymity of his daily life. The Hong Kong-based Information Centre for Human Rights in China cited an internal party document as saying that the authorities were never able to find him. The document suggested that the name provided by the Sunday Express was false. Mr Jiang was quoted as saying: "We can't find him. We got his name from journalists. We have checked through computers but can't find him among the dead or among those in prison."

Han Dongfang, the leader of a workers' union during the tumult, said: "I don't think anyone in the world can find this person ... Who he was is not important at all. What is important is that he was there, and by his act he gave encouragement to a lot of people."

Perhaps family and friends know who he is. Perhaps, one day, he will choose to step forward and make himself known to the world. He may, even now, be unaware of the mystique that surrounds his act.

Photographs of the face-off are banned in China and blocked on the internet by the Great Firewall of China. Few Chinese have ever seen the image that for the rest of the world symbolises the student movement of that spring in 1989.

If he were to come forward, he would end one of the great unsolved mysteries of the 20th century. But doing so might diminish the power of his courageous act: an Everyman who chose to show indomitable spirit in the face of the tyranny of dictatorship.

The deadly struggle

The 1989 Tiananmen Square protests began in April after the death of the liberal reformer Hu Yaobang, below right. On April 22, 50,000 protesters gathered in the square where Mao Zedong first proclaimed the People's Republic of China, to commemorate Hu, a former general secretary of the Communist Party, who had urged democratic reform

The number of people attending rose steadily and the demonstration turned from a commemoration into a broader protest against the Government. By the end of April more than a million people had gathered in the square at the centre of Beijing. The protests were embarrassing the Government and frantic changes were made to the schedule of a visit by the Soviet leader, Mikhail Gorbachev, below left. International attention focused on the protest as students began hunger strikes in the square

Zhao Ziyang, Hu's moderate successor as general secretary, publicly declared his sympathy for the protesters and asked for their forgiveness. He was subsequently removed from his post by party hardliners and remained under house arrest for the remainder of his life

On June 4, after seven weeks of protest, the tanks of the People's Liberation Army entered Tiananmen Square. In two bloody days they dispersed the remaining demonstrators and killed hundreds of unarmed people in nearby streets. The number is disputed but the government figure of 241 is widely believed to be too low. Thousands more dissidents were detained. The massacre drew international condemnation but halted momentum for democratic reform

Source: Times database

'It was the single bravest act I had witnessed'

Eyewitness Jim Sterba

Tears rolled down my cheeks as I watched him stand in front of those tanks. I wept later watching a video replay. And when I got back to my hotel room early the next morning, I had to wipe tears from my eyes to see my laptop screen as I wrote: "Something happened on the Avenue of Eternal Peace at noon yesterday that is going to make a lot of people think again about the meaning of courage.

"A lone man, in a moment that seemed an eternity, stopped the People's Liberation Army literally in its tracks."

It was the single bravest act I had witnessed in 20 years of covering wars, rebellions and assorted turmoil in Asia. The story of this little man's action was the most heartfelt and, I thought, the most symbolically important of many I'd written for the front page of The Wall Street Journal about the Tiananmen Square protests and crackdown.

But by the time it landed in New York, my editors had China fatigue. After weeks of pro-democracy demonstrations, the PLA had assaulted the square on the weekend of June 3 and 4, killing untold numbers of people. The rebellion was over. My story was an interesting coda. My editors buried it inside the Tuesday paper.

Now, 20 years later, I think maybe they were right. Nobody knows how close the rebellion, and the Communist Party power struggle behind it, came to plunging China into chaos. But it didn't happen. Instead the rebellion became an historical footnote, smashed by party elders led by Deng Xiaoping without a second thought. These ageing geezers, after all, had killed tens of millions of their people over decades in their quest to rule China and in their disastrous policies as rulers. Killing a few hundred or thousand more in the name of preserving order — and keeping China's new modernisation drive alive — meant nothing.

But I wasn't thinking of history at the time. Sometimes, reporters say, the news gets in the way of the story. Not this time. Here the story was encapsulated in one man's seven-minute act of defiance. He stood for extraordinary numbers of Chinese — not just students. (I spotted Foreign Ministry officials demonstrating in the square.) "Hey, come look at this," someone shouted from a seventh-floor balcony at the Beijing Hotel. We rushed to look. A man had walked out in front of a column of tanks and brought them to a clanking halt. He stood his ground for an eternity, it seemed. When the lead tank tried to flank him, he jumped into the path of its new course. He even jumped on to the tank and pounded on its gun turret with his fist.

By the time another man came out and pulled that brave little man away, the world had a visual record of an incident to inspire rebels, sober autocrats and perhaps some day change history after all.

Jim Sterba is a staff writer at The Wall Street Journal 'I can't confirm whether this young man was arrested'

Armed only with shopping bags, the lone man halts a column of tanks in an intrepid act that became a worldwide symbol of the struggle for freedom that was crushed in Beijing