Specialized jobs
It was not uncommon for specialized jobs of Ancient Korea to be assigned to people based on their social class. The concept of the "Four Occupations" provided a view of how jobs were valued in Ancient Korea.
The Yangbans were a part of society within the "sa" gentry scholars/elite at the highest level of the job-occupation system. They constituted the educated group of Ancient Korean society and were responsible for obtaining vast amounts of knowledge pertaining to all areas of society and culture in order to best be able to participate in governmental rule and decision-making.
The peasant farmers who owned land, referred to as the "nong", constituted the next highest level of the job-occupation system. The elite ruling society most closely identified with them in terms of owning land and wanted to maintain land-ownership as an important criteria in class status. It was also believed that the farmers feed society as a valuable service and should be accordingly recognized in the status hierarchy.
The artisans and craftsmen, referred to as the "gong", constituted the third level of the job-occupation system. Without the notoriety of being land-owners, the elite ruling society did not see the need to place this group on such a high level. Yet, since they did produce tangible items of great value to society, such as farming tools, military weapons and clothes, their importance did not go unnoticed with their job status placed just below that of the lowest land-owner level.
Traders and merchants belonged to the lowest level, or "sang", of the popular job-occupation system. They were seen as having some value to society, yet they also were thought to be primarily out for their own good whether or not their work truly benefitted the Korean culture. They brought in goods from other parts of the world for the Korean society to enjoy. That put them at the bottom of the job-occupation system.
There were a variety of other occupations that were not included within that system. For example, soldiers were, by definition, responsible for engaging in violent activity and such an occupation was not harmonious with the non-violent, culture of arts and intellect that was publicly promoted.