The Sui dynasty first established imperial civil-service examinations on a lasting basis.
The Sui reunified China in 589 CE after centuries of division. Its rulers expanded centralized administration and began using examinations to recruit officials based more on classical learning than solely on hereditary status. The system was developed and enlarged substantially by later dynasties.
The examinations tested knowledge of Confucian classics and, in later periods, literary composition and policy writing. They became a central route into official service, although wealth, schooling, family connections, and regional opportunity continued to affect who could compete successfully.
The Tang dynasty expanded the examination system, while the Song dynasty made it even more important in the structure of government and elite society. The examinations should not be confused with a modern fully open meritocracy: candidates faced intense competition, and the system favored men with access to years of classical education.