Market’s Echo of Tiananmen Date Sets Off Censors

“I want to thank all the stock traders!” wrote one microblogger.

“Maybe God does exist?” wrote another.

Whatever the reason, the strange trick that the stock market played on the Chinese Communist Party sent the country’s censors scrambling as well, prompting them to undertake unusually strenuous efforts to block references to the tragedy, which Chinese leaders have tried desperately to erase from their country’s consciousness.

In a nation where numerology is taken very seriously, the censors quickly began blocking searches for “stock market,” “Shanghai stock,” “Shanghai stock market,” “index” and related terms. They also deleted large numbers of microblog postings about the numerical surprise.

And even before tens of thousands of demonstrators clad mostly in black gathered at Victoria Park in Hong Kong for an annual candlelight vigil commemorating the Tiananmen killings, censors were also blocking searches for “Victoria Park,” “black clothes,” “silent tribute” and even “today.”

Not only did the broad index of the Shanghai exchange fall 64.89 points on Monday, but the index also opened that morning at 2346.98, a figure that, to some, looked like the date of the crackdown written backward, followed by the 23rd anniversary.

The Shanghai Stock Exchange Composite Index is calculated by adding up the market capitalizations of hundreds of stocks and then converting the sum into an index based on a value of 100 on Dec. 19, 1990. Richard W. Kershaw, the managing director for Asia forensic technology at FTI Consulting, a global financial investigations company, said that it would be almost impossible for anyone to coordinate the buying and selling of so many stocks to produce a specific result.

But hackers have targeted the computer systems at other stock exchanges in the past, and Mr. Kershaw said it was at least possible that this might have occurred in China. He predicted that the government would investigate, adding, “You can bet we’ll never hear the results.”

Chinese culture puts a very strong, sometimes superstitious, emphasis on numbers and dates. The Beijing Olympics started at 8:08 p.m. on Aug. 8, 2008, a time and date chosen for the many eights, considered an auspicious number.

The candlelight vigil in Hong Kong drew a crowd that organizers estimated at “over 180,000,” which would make it the biggest of the annual events since 1989. Organizers have estimated the crowds in 1990, 2009, 2010 and 2011 at 150,000.

The police here were more cautious, putting the turnout at 85,000; they had estimated the annual turnout from 2009 through 2011 at 62,800, 113,000 and 77,000, and the 1990 vigil at 80,000.

The turnout on Monday, on a humid evening under a luminous full moon, was particularly hard to calculate.

Six soccer fields in front of a large stage, the core of the park, filled up with densely packed crowds earlier than in previous years. That prompted people to spill over to a series of other fields in the park. Some fields had outdoor screens that were put up to display the proceedings; others had no such provisions, having not filled with crowds in past years.

There was also an unusually large turnout of people who appeared to be in their teens or 20s. Until the last several years, the vigils had been mostly attended by people in their 40s and older — those who had experienced soaring hopes for democratization in 1989, followed by crushing disappointment.

Andy Lo, 20, a university student, said that social media like Facebook had been filled this year with calls to attend the vigil. But he and others there were unable to explain why this had happened.

“I used to think it was just a ritual,” he said. “We want something to change, the voice for change is much stronger now, but I can’t account for it.”

Even 23 years later, the use of tanks and gunfire to disperse unarmed students and other Tiananmen Square protesters remains a point of bitter dispute in China and around the world.