The Censorate was a high-level supervisory agency in ancient China, first established during the Qin dynasty (221–207 BCE).
The Censorate was a highly effective agency during the Mongol Yuan dynasty (1271-1368). During the Ming dynasty (1368–1644), the Censorate was a branch of the centralized bureaucracy, paralleling the Six Ministries and the five Chief Military Commissions, and was directly responsible to the emperor. The investigating censors were "the eyes and ears" of the emperor and checked administrators at each level to prevent corruption and malfeasance, a common feature of that period. Popular stories told of righteous censors revealing corruption as well as censors who accepted bribes. Generally speaking, they were feared and disliked, and had to move around constantly to perform their duties.
The Censorate was divided into three branches (院).
The Palace Branch (殿院) was responsible for monitoring the behaviour of officials during audiences; it was staffed by In-palace equerry censors (殿中侍御史).
The Admonish Branch (台院) was responsible for monitoring the behaviour of the emperor, to ensure that he did not make mistakes and remind him of his duties; it was staffed by equerry censors (侍御史).
The Detection Branch (察院) was responsible for monitoring the behaviour of local officials; monitor censors (監察御史) would tour the country in circuits to ensure the proper discharge of the functions of government and good performance of local officials.