Three Offices, or Samsa (삼사·三司), is a collective name for three government offices in the Joseon Dynasty that functioned as major organ of press and provided checks and balance on the king and the officials. These were Office of Inspector General (Saheonbu·사헌부), Office of Censors (Saganwon·사간원), and Office of Special Advisors (Hongmungwan·홍문관).
While modeled after the Chinese system of Censorate, they played much more prominent roles in the Joseon government than their Chinese counterparts. Some historians credit the Three Offices for the absence of abuses by eunuchs that were prevalent throughout Chinese history.[1]
The officials who served in these offices, called "daegan" (대간), tended to be younger and of lower rank compared to other offices such as the Six Ministries but had strong academic reputations and enjoyed special privileges and great prestige. To be appointed, they went through a more thorough review of character and family background. The children of officials who were impeached for corruption and children of concubines were excluded, and only those who passed literary gwageo examinations could become a daegan. As it attracted the elite of Joseon officialdom, the Three Offices provided one of the fastest routes of promotion to top posts in the Royal Court and was almost a requirement to becoming a State Councillor.