Reading about restrictions in Beijing, and also about King Li of the Chou (or Zhou) dynasty, who reigned in the 9th century B.C.E.:
The king acted cruelly and extravagantly. The people in the capital spoke of the king’s faults. The Duke of Shao remonstrated, saying: “Your people can no longer bear your orders.” The king was angered. He found a shaman from Wey and had him watch for criticism. Whomever he reported was killed. The criticism subsided. [But] the feudal lords stopped coming to court. In the thirty-fourth year [of his reign], the king became even more stern. No one in the capital dared to say a word, but only glanced at each other on the roads. King Li was pleased. He told the Duke of Shao: “I was able to stop the criticism. Now they dare not speak.” The Duke of Shao said: “This is [merely] blocking up criticism. To block peoples’ mouths is worse than blocking a river. When an obstructed river bursts its banks, it will surely hurt a great number of people. People are like this, too. For this reason, those who regulate rivers dredge them and let them flow; those who regulate people broaden [channels] and let them talk. Thus, when a Son of Heaven presides over the government, from dukes and ministers [down] to [high-]ranking patricians, he makes them offer poems, [he makes] the Blind Musician offer songs, the Scribe offer records, lesser tutors offer admonitions, the blind offer rhapsodies or recitations, the hundred officers offer remonstrations, the common people pass their messages [to the king], close subjects present their corrections, and relatives amend or look into [the king's mistakes]. After the Blind Musician and the Scribe have given their instructions and the elders have ratified them, then the king deliberates on them. Because of this, things can be put into practice without opposition. People having mouths is similar to the land having mountains and rivers, from which the daily needs are drawn; and [it is also] similar in that there are highlands, lowlands, swampy lands, and irrigated lands, from which clothes and food are produced. When mouths are made to express words, [both] good and degenerative [ideas] will arise. To put the good ones into practice and to guard against the degenerative ones are the ways to make daily necessities, food, and clothing abound. As people have thoughts in their minds and express them through their mouths, if [the ideas] are constructive, you should finish them and put them into practice. If you gag their mouths, how many of them would support [you]?” The king would not listen. Then no one in the capital dared to say a word. Three years [later], they joined each other in rebellion, and attacked the king. King Li fled to Chih.
Ssu-ma Ch’ien (Sima Qian), The Grand Scribe’s Records, Volume I: The Basic Annals of Pre-Han China (ed. Nienhauser), Shiji 4 (142).