At the very top of this social hierarchy were the yangban who could be loosely classified as those who were eligible for high ranking government service due to passing civil service exams. They formed the elite of Choson society. The term 'yangban' was used to denote the dual role that the yanban had in both the military and civil service
Under the yangban, were the class of translators, scientists, doctors, translators, administrative clerks, and so on
And then there are the commoners whose rank and file comprised tenant farmers, craftsmen, and free laborers
At the bottom of the social hierarchy were the chonmin or "base" people. Slaves, butchers, prostitutes, and other entertainers formed this class. Slaves were emancipated in the 19th centurylink
Note that Japan abolished this slave system under Japan's rule.