The research started with questioning which factors made the Korean Armed Forces counterinsurgency operations successful during the Korean War in 1950-1953. To analyze the case study of the Korean War, this study applied Galula's COIN warfare theory and principles in Counterinsurgency Warfare as an analytical frame: the four laws and the eight steps. His theory was suitable for this study in terms of the level of war, clarity of theory, and historical and regional backgrounds that informed the theory's formation. As the results of analysis as well as the frame, the key factors contributing to the success of the COIN operations in the Jirisan region during the Korean War in 1950-1953 were: initial gains of population's support through the destruction of insurgency forces; deployment of COIN static units demonstrating the ability to win; successful control of the population to build their support and turn an active friendly minority into a majority; and finally, destruction of the insurgent political organization by continuous and intensive efforts. With the results, three implications seem the most obvious: the importance of the Jirisan region in COIN operations; continuous and intensive governmental efforts; turning the active minority to the majority is the key in COIN. The author hopes this study contributes to fill a gap in the COIN study on the Korean War.

Approved for public release; distribution is unlimited. The opinions and conclusions expressed herein are those of the student-authors and do not necessarily represent the views of the U.S. Army Command and General Staff College or any other governmental agency. (References to these studies should include the foregoing statement.)