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.
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.
Office of Inspector General
It monitored government administration and officials at each level in both central and local governments for corruption, malfeasance, or inefficiency. It was also in charge of advancing public morals and Confucian customs and redressing grievances of the populace. It was headed by Inspector General (Daesaheon·대사헌), who oversaw 30 largely independent officials. It is the largest and most senior office of Three Offices.
Office of Censors
Its chief function was to remonstrate with the king if there was wrong or improper action or policy. Important decrees of the king were first reviewed by censors, who could ask to withdraw them if judged improper. It also issued opinions about the general state of affairs. It was composed of five officials, led by Chief Censor (Daesagan·대사간).
While the primary focus for Office of Inspector General is the government officials and Office of Censors is focused on the king, the two offices often performed each other's functions, and there was much overlap. Together they were called "Yangsa," (양사) which literally means "Both Offices," and often cooperated in joint actions especially when they sought to reverse the king's decision. In their role as organ of press, they did not have actual authority to decide or implement policies, but had influential voice in the ensuing debate.
Office of Special Advisors
It oversaw the royal library and served as research institute to study Confucian philosophy and answer the king's questions. Its officials took part in the daily lessons called (경연), in which they discussed history and Confucian philosophy with the king. generally took place three times a day although few kings such as Taejong and Yeonsangun abolished them. Since these discussions often led to commentary on current political issues, its officials had significant influence as advisors. It was headed by Chief Scholar (Daejehak·대제학), who served concurrently in another high post (such as in State Council), and Deputy Chief Scholar (Bujehak·부제학), who actually ran the office. There was great prestige attached to being Chief Scholar in this deeply Confucian society.
The office was established in 1463 by King Sejo to replace Hall of Worthies (Jiphyeonjeon·집현전), which he abolished in 1456 when many of its key officials ("Six martyred ministers") became involved in the assassination plot in their effort to restore deposed king Danjong to the throne.
History
Three Offices of Joseon was inherited from Goryeo Dynasty, but its characteristic features were developed after neo-Confucianism became the ideological foundation in Joseon, especially during Seongjong's reign.