This Saturday (June 4) marks the 27th anniversary of the massacre that ended pro-democracy protests in Beijing’s Tiananmen Square. Since June 4, 1989, the Chinese Communist Party has tried its best to stop people from mentioning the incident and convince them that the whole thing never happened.

This was relatively easy when the party held tight control over everything people read and wrote. The internet has made the task much more difficult. The result has been an unending game of cat-and-mouse between internet users, who invent clever new ways of referring to the massacre, and government censors who identify and remove these terms as quickly as possible.

China Digital Times (CDT), a news site affiliated with the University of California, Berkeley, has assembled a list of 261 distinct terms that have been used on the Chinese internet to refer to the Tiananmen massacre, and have at some point been blocked by censors. The list includes straightforward terms like ”Tiananmen” and “June 4,” as well as more absurd examples of linguistic acrobatics that can circumvent censors, like “May 35” (meaning four days after May 31, or June 4).

Most of the terms are in Chinese, but sometimes to evade censors internet users write in English or Romanized Mandarin. Some terms—like “25th anniversary” and “24 years”—were only blocked temporarily, during a period of particularly heavy use, and may be allowed online today.