FWIW, the massacre isn't referred to as "Tiananmen Square" within China, it's called the "6-4 incident" (after June 4th, the day it occurred). I remember this always surprising us when working on google.cn (from the U.S. offices): [tiananmen square] is not blocked within China because no Chinese person ever searches for that (it's an English phrase anyway), but random numbers that contain "6" and "4" are, including Javascript code.