Three departments and six ministries system

The three departments and six ministries system was a very influential political system in Chinese history. It took shape after the Western Han Dynasty (206 BC - 24 AD), was officially established during the Sui Dynasty, and was further improved during the Tang Dynasty (618 - 907).

According to its name, this system divided the imperial government into three different sectors. The three departments included Zhongshu Sheng, Menxia Sheng and Shangshu Sheng; the six ministries were Li4 Bu, Hu Bu, Li3 Bu, Bing Bu, Xing Bu, and Gong Bu, which were branches of Shangshu Sheng.

Three Departments
To some extent, the functions of the three departments resembled the political system in the US - the separation of the executive, legislative and judicial powers.

Zhongshu Sheng, which could be described as the imperial Secretariat, was initially set up during the Kingdom of Wei of the Three Kingdoms Period (220 - 280). The main functions of this department were transmitting the emperor's intention, overseeing confidential files, and issuing government orders.
Menxia Sheng, was first set up during the Jin Dynasty (265 - 420). It was originally an attendant organ of the emperor. During the Northern and Southern Dynasties (386 - 589), this department gradually became the most important part of the imperial regime. During the Sui and Tang Dynasties, the Menxia Sheng, along with the Zhongshu Sheng, oversaw the confidential files of the government, discussed state affairs, checked official orders, and had the right to dispute or ban orders.

Shangshu Sheng, the Department of State Affairs, was one of the highest authorities of central government from the Wei and Jin Dnasties to the Song Dynasty (960 - 1279). Its major responsibility was to carry out orders which had been written by Zhongshu Sheng, checked by Menxia Sheng, and rejudged by the emperor.

Six Ministries
All six ministries were under the administration of Shangshu Sheng, and each ministry governed four smaller departments called Si.
Li4 Bu managed human resources as we might say today. It was in charge of appointing, dismissing, promoting, demoting, selecting, and evaluating state servants.
Hu Bu was primarily in charge of the territorial resources and financial affairs of the state. Specifically, it managed the farmland and the census register as well as the taxation and distribution of salaries.

Li3 Bu mainly dealt with rites. It was involved in the etiquette of military, diplomatic, religious, and school affairs.
Bing Bu chiefly took charge of the weapons and the books on strategies available for military officials and was also in charge of announcing military orders.
Xing Bu was like today's judicial court and police bureau. Its duties were to examine and approve all sorts of laws and to check and investigate criminal cases from all over the country.

Gong Bu was responsible for affairs related to a variety of projects, such as transportation, water conservation, farmland cultivation, and the employment of labor and personnel.

Judgment
Compared with the previous conventional political system, the Three Departments and Six Ministries system of the Sui Dynasty divided the administrative power formerly held by Cheng Xiang (the prime minister in ancient times) and limited the power of regional military generals. Therefore, the royal power held by the emperor was greatly increased.