from Taegu east to P'ohang-dong on Korea's east coast. The only major north-south road intersecting this line moves south from Andong through Yongch'on, midway between Taegu and P'ohang-dong. The only other natural entry through the line lies at the town of An'gang-ni, west of P'ohang-dong, which is situated near a valley through the natural rugged terrain to the major rail hub of Kyongju, which was a staging area for moving supplies to Taegu. Gen.Walton Walker—commanding the Eighth United States Army—chose not to heavily reinforce the area, as he felt the terrain made meaningful attack impossible, preferring to respond to attack with reinforcements from the transportation routes and air cover from Yonil Airfield, which was south of P'ohang-dong. With the exception of the valley between Taegu and P'ohong-dong, the terrain along the line was extremely rough and mountainous thanks to the Taebaek Mountains, which ran from north to south down Korea's east coast. Northeast of P'ohong-dong along the South Korean line the terrain was especially treacherous, and movement in the region was extremely difficult. Thus, the UN established the northern line of the Pusan Perimeter using the terrain as a natural defense. However, the rough terrain also made communication difficult, particularly for the ROK forces. Prelude The ROK—a force of 58,000— was organized into two corps and five divisions along the line; from east to west, I Corps controlled the 8th Infantry Division and Capital Divisions, while the II Corps controlled the 1st Division and 6th Infantry Division. A reconstituted ROK 3rd Division was placed under direct ROK control. Morale among the UN units was low due to the large number of defeats at that point in the war. The ROK had lost an estimated 70,000 men up to that point. At the same time forces of the US 5th Air Force supplied 45 P-51 Mustang fighters to provide cover from Yonil Airfield, and the US Navy had several ships providing support by sea. Evacuation of wounded and surrounded troops was carried out by the aircraft carriers and . The heavy cruisers and also provided fire support for troops operating in the town. The KPA troops were organized into a mechanized combined arms force of ten divisions, originally numbering some 90,000 well-trained and well-equipped men, in July, with hundreds of T-34 tanks. However, defensive actions by UN forces had delayed the KPA significantly in their invasion of South Korea, costing them