Key Facts
- Duration
- December 1951 – February 1952
- Total casualties (guerrillas)
- 5,800
- US advisers involved
- ~60
- Primary theater
- Jirisan mountain area
- ROK Army divisions committed
- 2 (Capital Division and 8th Division)
Strategic Narrative Overview
Launched in December 1951 under General Paik Sun Yup, Operation Rat Killer deployed two Republic of Korea Army divisions, multiple Korean National Police regiments, a ROKAF Mustang fighter-bomber squadron, and approximately sixty US advisers. Forces swept the mountainous Jirisan area in a systematic effort to locate, encircle, and destroy communist guerrilla units operating behind UN lines.
01 / The Origins
During the Korean War, as front-line fighting stabilized along the 38th parallel in late 1951, communist guerrilla forces continued operating deep within UN-held territory in South Korea. These irregular fighters, concentrated in the rugged Jirisan mountain region, were allegedly harassing nearly a third of UN forces and regularly attacking roads and railways critical to UN logistics, prompting a coordinated counter-guerrilla operation.
03 / The Outcome
By February 1952 the operation had concluded, inflicting approximately 5,800 casualties on guerrilla forces and significantly degrading their operational capacity. Although the guerrillas were greatly weakened and no longer posed a major threat to UN rear areas, residual insurgent activity persisted, and a resurgence remained a concern until the armistice ended the Korean War in 1953.
Belligerents & Mobilization Analysis
Side A
3 belligerents
Paik Sun Yup.
Side B
1 belligerent