The jungin (中人), as the name says, stood in the "middle" (中) between yangban and commoner. Less a status sharply defined by law than a real stratum that hardened as Joseon society ran its course, the jungin broadly encompassed various professional occupations between the ruling class and the common people. They passed down their working skills across generations and served as the cogs that kept society turning — yet however talented, they could scarcely rise to the high offices the yangban monopolized.
Technical officials — the nation's experts
In the narrow sense, jungin refers to technical officials who entered service through the technical examination (japgwa). Among them were interpreters (yeokgwan), who dealt with and translated for foreign envoys; physicians (uigwan), who handled medicine; officials of the Gwansanggam who dealt with astronomy and the calendar; legal specialists (yulgwan); and court painters (hwawon). Interpreters in particular travelled abroad with envoys and took part in trade, sometimes amassing great wealth.
Hyangni and seori — the hands and feet of administration
The hyangni (鄕吏), local clerks who handled practical affairs in provincial offices for generations, and the seori, low-ranking staff of central offices, are also classed as jungin. Magistrates left when their terms ended, but the hyangni were rooted in their region and did the actual administration — collecting taxes, processing documents — and so held considerable influence in local society.
Discrimination and the drive to rise
Despite their expertise, the jungin were shut out of core posts such as the "pure and essential" offices (cheongyojik). In the late Joseon period, especially the 19th century, jungin therefore mounted collective efforts to lower the barriers to office. After the ports opened, interpreters and physicians well-versed in foreign languages and practical knowledge came to the fore at the front line of adopting modern civilization, at times emerging as leading figures of a new age.