Operation Killer

Operation Killer was the start of the second major counter offensive launched by United Nations forces against the People's Volunteer Army and the North Korean Army during the Korean War between 20 February and 6 March 1951. The offensive was formulated by General Matthew Ridgway with the goal of annihilating enemy forces below the Arizona Line and was immediately followed by Operation Ripper.

Battle
The 2nd Division jumped-off on "Operation Killer" on 22 February. The initial advance was slow, not so much due to resistance as to terrain. The sector assigned to the 2nd Division presented enormous problems. However, by 1700 hours both the 9th and 38th Infantry Regiments had reached the Chuchon River where swift waters and a lack of bridges delayed crossing. The engineers constructed a foot bridge for immediate use of the 9th Infantry and, in the 23rd Infantry Regiment's zone of advance, tanks of the regimental tank company were used to ferry people to the north bank. The 9th Infantry ran into moderate resistance on 23 February but with all three battalions teaming up, an enemy force of 2,000 was routed, dispersed to the north, leaving their dead and wounded behind. The Second Battalion of the 23rd Infantry, with the 37th Infantry FA Bn attached, moved east into the 7th Division zone on 26 February in preparation for an attack on the following day on Ungyo-ri, an important town on the Hoengsong-Pangnimni road. The 9th Infantry, after securing Haanhung-ni, west of Ungyo-ri, sent a battalion eastward along the road in anticipation of an enemy withdrawal from Ungyo-ri when the Second Battalion of the 23rd Infantry launched its assault. The evening of this last day of February found the 2nd Division in positions astride the Hoengsong-Pangnimni road in its sector and preparing to continue its advance to Phase Line Arizona which paralleled the road roughly 7,000 meters to the north. Ahead of the Division were strong elements of the 17th and 18th CCF Divisions and lesser elements of the III and V North Korean Corps which were retreating slowly to the north in the face of the grinding X Corps offensive. Intelligence reports indicated the foe intended to delay the advance as much as possible while he prepared fixed defenses north of the 38th parallel. "Operation Ripper," was designed to carry UN forces to the 38th Parallel. Similar to "Operation Killer" it aimed at maximum destruction of enemy personnel and equipment with minimal friendly casualties. It wasn't the character of the opposition so much, although at times throughout the month it was fanatic and as strong as any ever faced. It was the terrain, coupled with alternate spring thaws, rains and days of sub-zero freezes which hampered every activity and wrought unprecedented burdens on every unit and operation. The operation concluded by the end of March.

Aftermath
Over the fourteen days the two corps took to reach and consolidate positions along line Arizona, each reported having inflicted substantial enemy casualties. The IX Corps alone reported 7,819 enemy killed, 1,469 wounded, and 208 captured. But from the outset it had become steadily clearer that the primary objective of Operation Killer of destroying all enemy forces below the Arizona line would be only partially achieved. The enemy forces' head start in withdrawing, their disinclination to take a defensive stand below the objective line other than in spotty delaying actions, and Eighth Army difficulties in negotiating the ground had prevented any other result.