Examined in this article, are the contents and meaning of Chungseon-wang’s decision to install New Mok/牧 units in 1308, and then his decision to turn them into new Bu/府 units in 1310. With Chungseon-wang’s efforts in 1308, the previous local system which was composed of “5 Do provinces, several Local Overseers(Gye’su-gwan, including only 8 or 9 Mok units) and other Ju, Bu, Gun & Hyeon units,” was modified to display “5 Do provinces, more than ‘22 or 23’ Mok units to assist the provinces, and other Ju, Gun & Hyeon units.” And then in 1310, 15 of the 1308’s Mok units became “new Bu” units.
Before 1308, the exact nature of the relationship between the Do provinces and the Mok “Overseers” was unclear. Both entities were designed to oversee large areas. The reason there had been no jurisdictional problems between Do and Mok units before, was because the Do provinces had not yet been formally established. They had been in flux and their functions had been continuing to shift, ever since the end of the 10th century. But coming into the early 13th century, they were finally formalized with their number fixed as 5, and their functions came to overlap with those of the Mok units, which was (for both of them) to administratively oversee designated wide areas.
So Chungseon-wang decided to designate the role of the existing 8 or 9 Mok units as ‘assisting’ the Do provinces, and at the same time additionally created total of 15 new Mok units as entities that would assist the Do provinces as well so that there would be no gaps within the Mok network, without which the Do provinces would not be able to govern the local society properly. And in 1310, to bring a hierarchy system to his newly invented local structure which would ensure efficient and effective ruling of the entire local society, he turned all 15 new Mok units into new “Bu” units, and placed them under Do provinces, as well as below the 8 or 9 Original Mok units.
His decision to create 15 new Mok units was an attempt to use elements from Goryeo’s past local system, which was to create more ‘traditional’ Mok units. Yet his decision to turn them all into new Bu units was a result of adopting a rather foreign concept, the Bu concept from the Mongol Yuan empire. This interesting experiment of Chungseon-wang was successfully pulled off, and this new system he designed managed to survive until the end of the Goryeo dynasty.