The Pohang Operation was an anti-guerilla operation during the Korean War between United Nations Command (UN) and North Korean forces near Pohang from 10 January to 11 February 1951.
Background
Following their withdrawal from the Battle of the Chosin Reservoir and their evacuation from North Korea in December 1950, the US 1st Marine Division began a period of rest, reorganization and rehabilitation at Masan, South Korea about south of the UN's Main line of resistance.
When the Chinese People's Volunteer Army (PVA) launched their Third Phase Campaign on 31 December 1950, the Korean People's Army (KPA) simultaneously attacked in eastern Korea breaking through the positions held by the Republic of Korea Army. As part of the KPA assault the 10th Division attacked towards Andong. The US Eighth Army alerted the 1st Marine Division to be ready to move northeast to Pohang, a fishing village about a third of the way up Korea's east coast, in order to protect Eighth Army lines of communication and backstop some shaky ROK divisions. The Pohang area had great strategic importance because it included a significant stretch of the Eighth Army main supply route (National Route 29), housed several key road junctions, included the only protected port on the east coast still in UN hands, and was the site of K-3 one of the few modern airfields in eastern Korea. This mission was confirmed on 8 January, but it had by then been modified to include the entire 1st Marine Division which was not assigned to a corps, but would instead be directly under Eighth Army operational control. The division staff cut orders on 9 January, and the Marines began moving out the next day with the maneuver elements going by truck and the support units by air, rail, and ship.
Operation
The operation began with a week-long movement from Masan to Pohang starting with the departure of the 1st Marine Regiment organized as a regimental combat team, on 10 January. A motor convoy carried elements of the 1st Marines; the division Reconnaissance Company; the 2nd Battalion, 11th Marines; Company C, 1st Engineers; and Company D, 1st Medical Battalion, on a 10-hour journey from Masan to Yongchon. Upon arrival at Uisong the next day, the regimental combat team began patrolling a section of road. Two days later, the reinforced 1st Battalion, moved north to occupy Andong. A key crossroads about inland from the sea, it was the site of US X Corps' rear headquarters as well as two dirt airstrips (one of which was long enough to handle cargo planes, but the other able only to service light observation aircraft and helicopters). With the arrival of the division's two other regimental combat teams, the 5th Marine Regiment patrolled the coast from Pohang to Yongdok and defended K-3, while the 7th Marine Regiment occupied centrally located Topyong-dong. The last Marine units disembarked from LSTs at Pohang on 17 January.
Although there was some limited discussion about small-scale amphibious operations by Eighth Army commander General Matthew Ridgway when he visited the 1st Marine Division command post at Pohang, these never came to fruition. Instead, he ordered the Marines to defend an east-west line just north of the Andong-Yongdok Road and to simultaneously protect the north-south-running Eighth Army main supply route. General O. P. Smith faced a dilemma because he was at first uncertain about which of these assignments should receive the highest priority. Should he deploy to guard against an all-out attack on the main line of resistance by PVA/KPA regular forces from the north or be prepared for counter-guerrilla operations against small groups of infiltrators? Intelligence reports indicated that the latter was the most likely course of action. Small KPA bands had already proved extremely troublesome by intermittently cutting supply lines and occasionally attacking outposts between Wonju and Taegu so continued guerrilla actions were considered probable. General Smith was well aware that the Marines would not be manning an exposed position. Several ROK divisions screened the Marine northern flank, the Sea of Japan protected his eastern flank, and hilly terrain made the western approaches inaccessible to armor. Smith, therefore, decided to emphasize mobile security operations and made linear defense a secondary mission.