고려의 수군전략과 후삼국통일

Abstract

This paper is based on a military history perspective of naval strategies and activities that were believed to be established in the foundation era of the Koryo dynasty, as a means to achieve unification of the Later Three Kingdoms. The background of Koryo's active naval activities include a series of navy-strengthening operations at the end of Taebong period, as well as a succession of naval strategies, which aimed for the ultimate unification of the Later Three Kingdoms formulated during contemporary times. The construction of naval power in the latter Taebong era consisted of building warships, recruiting generals and officers who could command, and the increased number of soldiers. The reasons for Koryo's effort to increase its naval power were to continue naval dominance in the southwestern seas, whose design already took effect during the Taebong regime, and to secure war resources, thereby taking the initiative of the unification warfare. In order to implement such a grand plan, the Koryo once even thought about undertaking major expeditions along strategic coastlines in the southwest. However, expansion of sea control was difficult to accomplish due to its unstable political climate in the founding years. Instead, the Koryo dynasty chose an alternative to safely secure unification military expenditures from the southwest - by enhancing the base of naval activities with the institution of Dhohangsa (water-transportation office) and Najudo-daehengdae (temporary local minor government to administer the Naju region). Koryo endeavored to extend its sea power, while simultaneously preparing finances for war through strengthening the infrastructure for naval activities. In April of 927, the Koryo embarked on the sea expedition, led by admirals Yeongchang and Neungshik, to attack Gangju and its neighboring sea coasts. Such a venture was significant as it extended Koryo's marine sphere of influence to the south sea region of the peninsula, which was not possible during Taebong times. However, in September of the same year, Koryo's critical defeat in the battle of Gongsan led to Later Baekjae's containment of the southwest marine route to Naju, which in turn had put Koryo's sea expansion to a halt. This also changed the navy strategy to ensure the sea route between Songak and Naju, rather than enlarging coastal sea control. When the navy of Later Baekjae was threatening the very coastal regions of Gaesung at the time, it was only natural that Koryo's sea power was limited to southwestern seas around Naju. Ironically, it was this concentration of marine traffic that led to the dramatic escape of ex-king Gyeonhwon to Naju, who was then escorted to Koryo for surrender, thereby advancing the unification of the Later Three Kingdoms. Hence, Koryo's grand design of unification ultimately was indebted to the developmental succession of naval strategies of its predecessor, the Taebong kingdom.