The reorganization of Gaegyeong(開京) and its regions nearby went along the lines of Goryeo’s national reform of its provincial government system. A detailed history is introduced in the Wanggyeong Gaeseong chapter(王京開城府) of the Goryeosa(高麗史) Jiriji(地理志), with Gaegyeong and its nearby areas reorganized in 995 and 1018 respectively since Taejo(太祖) installed Gaeju(開州). The regions nearby Gaegyeong, in particular, were called Gyeonggi(京畿) after 1018. The provincial government system of 1018 mainly constituted the reorganization of Ju-hyeon(主縣) and Sok-hyeon(屬縣) and setting up a Gyaesu-gwan system(界首官制), with Gyeonggi also reorganized in accordance.
The Gyaesu-gwan system involved Gyeong(京), Mok(牧), and Dohobu(都護府) taking a mediating role in the administrative system between central government and Ju-hyeon. However, Gyeonggi was set up as a directly subordinate(直隸) to the Sangseo-doseong(尙書都省), meaning a Gyaesu-gwan did not exist in Gyeonggi. This meant that the Gaeseong Hyeonryeong(開城縣令) and the Jangdan Hyeonryeong(長湍縣令) would directly send administrative documents to the Sangseo-doseong, with the Gyaesu-gwan of Goryeo’s unique tasks including Sangpyo-jinha(上表進賀), Hyang-gong-seonsang(鄕貢選上), and Wae-ok-su chu-geom(外獄囚 推撿). Because Gyeonggi did not have a Gyaesu-gwan, its unique tasks are assumed to have been handled by the Gwangju-mok(廣州牧) or the Anseo-daedohobu(安西大都護府), who were the Gyaesu-gwan nearby.
Gyeonggi, installed in 1018, was ruled by the Hyeonryeong, and the Hyeonryeong was the lowest position among the provincial posts of Goryeo. The tasks of the Gyaesu-gwan which were dealt at the level of large towns corresponding to Gyeong, Mok, and Dohobu could not be handled by the Hyeonryeong. Also, the fact that the Gyaesu-gwan exam of Gyeonggi was handled by the Gyaesu-gwan nearby factored as a disadvantage for Gyaesu-gwan exam applicants.
The reorganization of Gyeonggi in 1062 was carried out to revise and supplement the issues resulting from the absence of a Gyaesu-gwan as well as the issues resulting from Hyeonryeong rule. The Gaeseong-hyeon was upgraded to Gaeseong-bu(開城府), and the 11 hyeons subordinated to Sangseo-doseong were transferred. The introduction of the Gaeseong-bu increased the level of the dispatched provincial official. Mainly figures corresponding to the senior seventh rank Chamsang(叅上) and up to the senior sixth rank Wonwaerang(員外郎) were dispatched as the Jigaeseongbusa(知開城府事, Minister of Gaeseong-bu).
The Gaeseong-bu corresponds to the Jijubugunsa(知州府郡事) among the levels of towns that comprised Goryeo’s provincial government system. The status of the Jijubugunsa was identical to the Bang-eo-sa(防禦使), and his stipend to the Pan-gwan(判官) of the Gyeong, Mok, and Dohobu. Goryeo, on principle, dispatched figures up to the junior seventh rank as Jijubugunsa and Bangs-eo-sa, and actual cases confirm dispatches between the junior seventh rank and senior sixth rank. However, candidates for the Gyaesu-gwan Pan-gwan were senior seventh rank Chamsang and up to the senior sixth rank, which agrees with the appointment principle of the Gaeseong-bu. Therefore, the Gaeseong-bu can be understood as having a status corresponding to the the Gyaesu-gwan Pan-gwan.

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