By 7 January the UN forces had pulled back to a modified Line D extending from Pyongtaek on the west coast to Samchok on the east and taking in Yoju and Chechon. General Ridgway sent telegrams to all corps commanders expressing dissatisfaction with the personnel and material losses inflicted on the enemy during the withdrawal. “I shall expect,” each message concluded, “utmost exploitation of every opportunity in accordance with my basic directive.” That evening, foreshadowing the offensive operations he was contemplating, the commanding general ordered a reconnaissance-in-force by a reinforced infantry regiment north to Osan to search out the enemy and inflict maximum punishment. No contacts were made, nor did strong patrols sent out by U.S. IX Corps flush out any sizeable groups of Chinese. But the Eighth Army had served notice that it intended to regain the initiative at the first opportunity. One more blow remained to be absorbed. On the 8th the Communists struck in the Wonju area with an attack of four divisions. Elements of the newly reorganized 2d Infantry Division were forced to give up that important highway and rail center after counterattacks failed. The enemy now directed his main effort along the Chunchon-Wonju-Chechon corridor, and North Korean guerrilla forces infiltrated through the gap between the U.S. X Corps and ROK III Corps. The salient created by this CCF attack caused Line D to be modified again so that in the center it dipped sharply downward to Chungju before curving northeast to Samchok (Map 4). _Marine Aircraft in the Battle_ The pilots and aircrewmen of the three carrier squadrons and the land-based jet squadron were the only Marines in a position to take an active part in the battle. With but one TACP per division, close air support was out of the question for the ROKs on New Year’s Day. Control facilities were severely strained when scores of UN fliers made use of the frequencies which the Mosquitoes employed for tactical air direction. The voices were all in the English language, but with more than one person doing the sending, shrill side noises sliced in to garble the whole into a cacophony of jungle sounds. A Mosquito trying to coach a fighter-bomber attack at the crossings of the Imjin might be drowned out by a distant pilot calling up a controller in the Hwachon Reservoir Area.[31] [31] USAF Hist Study No. 72, _U. S. Air Force Operations in the Korean Conflict_, 1 Nov 50–30 Jun 52, (hereafter cited as AHS-72) pp. 188–196. The term “net” denotes a network of radio stations, all on a single frequency for a specific purpose. As a consequence, there was no coordinated air-ground attack in direct support of the man in the foxhole. Most of the JOC effort was directed to the enemy’s rear in an effort to block supporting arms, reinforcements, and supplies.