The nine-rank system, also known as the nine-grade controller system, was used to categorize and classify government officials in Imperial China. Created in the state of Cao Wei during the Three Kingdoms, it was used until the Song dynasty, and similar ranking systems were also present in the Ming dynasty and Qing dynasty. Prior to the nine-rank system, official positions were denoted by their salary paid in number of bushels of grain. For example, during the Han dynasty, the highest-ranking officials were classed as wandan (萬石), meaning ten thousand bushels, and were paid 350 bushels of grain per month. The lowest ranking petty subofficials were paid in pecks, worth less than 100 bushels per year. A similar system was also used in Korea. In Japan, the Twelve Level Cap and Rank System was adopted in 603 during the reign of Empress Suiko. History Background The Nine-rank system was a reorganization of the Han dynasty practice of recommending noteworthy locals for political office. Since 134 BCE, during the reign of Emperor Wu of Han, the Han court relied mainly on nomination by local magnates and officials as a way of identifying talent, by nominating them under titles such as Xiaolian (, Filial and Incorrupt) or Maocai (, of Outstanding Talent). The nine-rank system was created after the end of the Han in 220 AD when Chen Qun, a court official from the state of Cao Wei, proposed it as a way of organizing the state bureaucracy. It was called the "nine-rank method for recruiting men for office" (Jiǔ pǐn guān rén fǎ; ). During the Song dynasty it became the "system of Nine ranks and impartial judges." Chen Qun's reform was a way of systematizing the selection of candidates for political appointments in two ways: by creating a common scale of nine ranks to evaluate a person and by appointing ontrollers () in the court to grade officials on the scale. In practice, not only potential entrants but also existing officials were graded, creating two parallel systems: a "candidacy grade" and a "service grade" . The system was ostensibly based on a few criteria: moral probity, administrative ability, and the contributions of the person or his family to the newly-created Cao Wei regime. In practice, descent also played an important role; the service grade of a candidate's father had a bearing on their candidacy grade. The nine-rank system was originally intended