ONI’s testing found wide variation in whether sites on the Tiananmen Square incident could be
accessed, depending on the search term used. Chinese language sites related to searches for politically
sensitive descriptions, such as “massacre” and “six four,” were virtually inaccessible during our testing; we
found moderate levels of inaccessibility for English language sites pertaining to the search term
“Tiananmen massacre” (we did not test the terms “six four” or “Tiananmen event” in English since they
generated too many unrelated sites). We found filtering of 70% of Chinese language sites related to a
search for Zhao Ziyang, the former leader of China’s Communist Party who was removed from his post for
opposing the repression of the Tiananmen demonstrations. Surprisingly, URLs listed in response to a
search for “Tiananmen Square” itself were only moderately inaccessible for both Chinese and English
language sites.

http://www.opennetinitiative.net/studies/china/ONI_China_Country_Study.pdf