New Artificial Intelligence has helped detection and content blocking censors at Chinese internet companies reach unprecedented levels of accuracy ahead of the 30th anniversary of the Tiananmen Square pro-democracy protests on June 4th.

The anniversary of the bloody crackdown has been dubbed the most sensitive day of the year for the China’s internet, and President Xi Jinping has further tightened state control over what the Chinese can search.

Raft technology is being deployed to wipe Tiananmen from China’s internet, with posts alluding to dates, images and names associated with the protests being automatically rejected and censored.