At the outset, hearing of the 23rd anniversary of anything just doesn't seem significant.

That is until you learn that the commemoration still draws 150,000 people to a park in Hong Kong, and that to this day, a government, in this case China's, still refuses to publicly acknowledge that an incident, where hundreds to thousands of people may have been killed, ever happened at all.

While the June 4 Tiananmen Square crackdown is well known outside the country, officials have been relatively successful in ensuring silence within.

The fact that more than a million students demonstrating for democracy gathered in the spring of 1989, and that tanks and soldiers were used to violently end the protest is not taught in any school textbooks.

An estimated 50,000 specially tasked online police block key word searches, such as “June 4”, on sites like Baidu, China's equivalent to Google.

And in present-day Tiananmen, the anniversary will go by as if it were any other day. Evidence of the “massacre” that some rights groups allege, has long been swept away.

Cracks forming

In recent days, there have been attempts in various cities to commemorate the event, but those who have tried, have been harassed, detained or placed under house arrest.

Despite the control, cracks are forming within the wall of silence.

Hong Kong enjoys unparalleled freedoms due to its status as a “Special Administrative Region”. And it’s here that the mayor of Beijing during the Tiananmen Square incident has just released his memoir. In it, he recounts the crackdown, calling it “regrettable” … and “avoidable”.

While still far from an official recognition, the memoir stands as an account coming from the highest level of authority to date, and is significant.

But will it lead to more?

Bao Pu, the publisher of the memoir, who himself was in Tiananmen Square 23 years ago, remains doubtful, saying for the government to publicly address June 4, there would need to be a move towards political reform.

That is certainly what the crowds gathering in Victoria Park in Hong Kong are calling for. Attending the annual vigil will be Fang Zheng, a fourth year student studying sports in 1989, he lost both legs after a tank rolled over him.

The ceremony will also include the reading of a letter from a new generation of rights activist, Chen Guangcheng. The blind lawyer recently made headlines for his incredible escape from house arrest, and his flight to freedom to the US, after negotiations with Chinese authorities. Officially, Chen is "studying" law in America.

Symbolically, Chen represents the past and present reality of those who try to challenge the country’s authoritarian system they must do so from the outside.