In China, Maura Cunningham says, if you're going to hold an online discussion of the Tiananmen Square massacre, you'd better speak in code.
Don't mention June 4, the date the tanks rolled against unarmed protesters. Instead, try "May 35th" - a count of that month's 31 days plus four in June. It's a way around the censors and to avoid the lurking presence of the state security apparatus.
The game being played between citizen and government isn't exactly cat-and-mouse, said Cunningham, a scholar of Chinese history from Philadelphia.
It's more like Whac-A-Mole.
On Thursday, Cunningham, 31, will explore new and ominous shifts in digital media and dissent at what is expected to be a crowded St. Joseph's University conference on Tiananmen, timed to the 25th anniversary of the 1989 protests.
"The Internet is a bigger and bigger part of life in China," Cunningham said in an interview. "But it's becoming more and more complicated."
The symposium, called "Tiananmen at 25," is free and open to the public. It gathers some of the world's top experts on the massacre and begins what promises to be a season of international remembrance.
Harvard University holds its own seminar two days after St. Joseph's. The University of Southern California's U.S.-China Institute released a video on how journalists covered the protests.
Among the new books is The People's Republic of Amnesia: Tiananmen Revisited, by Beijing-based NPR correspondent Louisa Lim, who gave the keynote speech here Wednesday.
Lim, speaking to about 100 people in Mandeville Hall, described the Communist Party's successful effort to scrub the history and memory of Tiananmen from society.
"How can people have forgotten something that occurred in living memory?" she asked.
It turns out that it's not that difficult. The massacre doesn't appear in history books. Internet searches for Tiananmen bring up tourist information. And people, she said, face punishment or harassment if they bring up the protests.
Lim showed the famous photo of the "Tank Man" - the anonymous figure who stopped an advancing line of tanks after the killings. Then she described an experiment: She showed the photo to 100 Chinese students at four top universities. Only 15 could identify the picture, and several were nervous to have that knowledge.
"It looks like Tiananmen," one told her. "But it can't be."
Today, the huge square in Beijing's center is some of the world's most sensitive and surveilled real estate, a space fraught with historical, political, and emotional implications.
Its open plane is traversed each day by thousands of tourists from around the globe - and by plainclothes and uniformed security forces. Looming from the Gate of Heavenly Peace is a giant, iconic portrait of Mao Tse-tung.
The nature of the square changed forever during a few weeks in spring 1989. The death of former Communist Party General Secretary Hu Yaobang, a popular, open-minded reformer, led thousands of students and young people to march to the square in mourning.
More protesters arrived over the coming weeks, eventually numbering in the hundreds of thousands. They demanded government accountability, freedom of speech and the press, and they even built an ersatz Statue of Liberty figure called the Goddess of Democracy.
A sense grew, as news coverage spread worldwide, that the regime would be toppled, as others had fallen in Poland, Hungary, and Czechoslovakia.
Instead, on June 4, the Chinese government ordered the military to clear the square. Army units advanced from every direction, opening fire on protesters, bystanders, and people in nearby buildings. An accurate death toll has never been established, though estimates range from a few hundred to a few thousand.
"It's vital that we keep the memory and lessons of those weeks alive," conference organizer James Carter, a St. Joseph's China expert, said in a statement, "partly to understand China more fully, but also to prevent the people who died standing up for their beliefs from being erased from history."
In a country where it's foolhardy to gather publicly to demand democratic reforms, dissent has moved online, onto a shifting landscape of chat rooms and social-media platforms.
Cunningham, who grew up in East Falls and graduated from St. Joseph's, has seen the change. A former editor of China Beat - "Blogging How the East is Read" - and a visiting scholar at the Shanghai Academy of Social Sciences, she has been traveling in China for a decade.
In the mid-2000s, she noticed that a few U.S. or British websites were difficult to access in China. Today, more and more are inaccessible. Facebook is blocked. So are Twitter and YouTube. And the New York Times.
As a scholar, completing her doctorate from the University of California, Irvine, Cunningham found the squeeze on information sparking her interest in how people find ways around restrictions on "subversive" opinions.
Censored words include not just massacre and tank, but also mentions of Tibet, Taiwan, and the restless autonomous region of Xinjiang.
It's the big discussion groups and most-read Internet posters drawing government attention, Cunningham said. As in this country, a single, potentially controversial, post can easily pass unnoticed.
The government simultaneously censors and embraces the Internet, opening its own accounts to connect with people and promote its ideas.
In the last year, there has been a noticeable tightening online and a crackdown on those who voice complaints. The uncertainty over who else may be reading has pushed many discussions onto networks like WeChat, where users converse with people they know.
"It limits the spread of the idea," Cunningham said, "but people feel safer."
Many people think everything on the Internet is censored in China, but it's more complicated than that, she said. What's acceptable today might be deemed subversive tomorrow.
"The line is constantly shifting," Cunningham said. "It's really hard to know what will get you in trouble."
"Tiananmen at 25" is free and open to the public. Thursday's session begins at 9 a.m. at Mandeville Hall at St. Joseph's University. For more information: http://www.sju.edu/int/academics/cas/resources/tam25/EndText