Located in the northeast of the Korean peninsula Hamgil Province was integrated as part of Goryeo’s Northeastern Frontier District in 1356 (5th year of King Gongmin’s reign). It was thereafter named Yeonggil Province in 1413(13th year of King Taejong’s reign), Hamgil Province in 1416(16th year of King Taejong’s reign), and Yeongan Province in 1470(1st year of King Seongjong’s reign). As such, various names, Northeastern Frontier District, Yeonggil Province, Hamgil Province and Yeongan Province, were given to the same region across differen tperiods.
Aboriginals, Jurchen and Mongolians historically resided in this area since the Goryeo dynasty. The majority of Jurchen living in this area were naturalized as Joseon commoners shortly after the foundation of Joseon dynasty. As such, unique social manners and customs formed as a result of the cohabitation of Goryeo and Joseon nationals and naturalized locals in this area. The practice of Sejeon gwanha (Hereditary hired laborers), under which local powers or barbarian leaders (Jurchen) handled commoners under their authority like private slaves constitutes one of the unique social manners and customs that existed in this region.
Local power holders concealed the existence of these commoners in order to keep them as their private slaves. These commoners were expected to serve out their duties to the state, including military conscription and corvee labor. However, as they were registered as hyeopho (people who were subordinate to their main family) rather than gunho (military householders), they were not mobilized for the military. Although the Joseon government was aware of this situation in Hamgil Province, the problem of hyeopho in Hamgil Province proved hard to uproot over the short term, having being a long-accepted custom in the area.
The problem of Sejeon gwanha, which lasted until the reign of King Sejo, finally began to be resolved following the Yi Siae Rebellion of May 1467(13th year of King Sejo’s reign). King Seongjong determined that the Sejeon gwanha under the control of local power holders in Hamgil Province represented a force for rebellion in such local areas. In addition to King Seongjong’s political determination, the necessity to sever private dominant-subordinate relationships was also highlighted. As a result, the state decided to longer accept the uniqueness of Hamgil Province, a decision that was also in keeping with the system in place in the southern provinces where the state was directly responsible for military conscriptions. In keeping with this logic, the decision was made to remove the custom of Sejeon gwanha found only in Hamgil Province.
Following this process, Hamgil Province became unified under Joseon. The uniqueness of Hamgil Province, which has heretofore been regarded as being heterogeneous, provides a clue to the actual diversity of Joseon history. The Sejeon gwanha of Hamgil Province represents a small but salient example of how diversity became unified during early Joseon.