In addition to filling in its own organic regimental units, the 2nd Division also had attached to it the newly arrived French Battalion, the Netherlands Battalion, and the reorganized Ranger Company, which had previously been attached to the 25th Infantry Division. It was now renamed the Ist Ranger Company. Capt. Vaun was the new commander of the Ranger Company. He transferred from the G-4 Section of the 25th Infantry Division when he asked for a combat assignment. On 15 December, the 2nd Division G-4 said the division had been reequipped sufficiently to make it combat effective. It was nearing the point where it could once again assume a combat role in the rapidly expanding Eighth Army line across the width of Korea. This rapid reequipment of the 2nd Infantry Division had been made possible by emergency shipments from the United States and prompt shipments of some major equipment from depot stocks in Japan.
From 13 to 19 December there was a bewildering series of changes in plans for the 2nd Infantry Division. Most of the division was instructed to buttress the western defenses around the mouth of the Han River, Kimpo airfield, and the Seoul bridges. But the 38th Infantry Regiment received instructions to prepare to move to the central area around Wonju. The Division Operational Plan No. 1, 16 December, called for the division to move to the Wonju-HoengsongChungju area in the central mountains and to establish blocking positions to deny enemy movement south along the Hoengsong-Chungju axis. The army made a final decision on the employment of the 2nd Infantry Division on 19 December when it issued a Top Secret Operational Directive ordering the 2nd Infantry Division to the Chungju area. The division began moving to the new area on 21 December over icy roads. The 38th Infantry Regiment on 22-23 December arrived at an assembly area six miles south of Chungju, and the 9th Infantry moved to Chungju during 23 and 24 December. It had only 50 percent of its organic transportation when it received the order to move. The 23rd Infantry moved to Chungju on the twenty-second, closing there on 23 December.
On 23 December, 2nd Division Operational Order No. 13 gave the division mission as securing the Eighth Army east flank. The 23rd Infantry was to block on the Wonju-Chungju and Chungju-Chipo-ri roads; the 38th Infantry was to occupy Wonju and defend the Wonju-Chechon-Andong road; the 9th Infantry was at Chungju in division reserve; the 72nd Tank Battalion was in the vicinity of Sangju, south of the main mountain barrier that was an obstacle to north-south movement; and the 1st Ranger Company, attached to the 38th Infantry, was to maintain contact with the ROK II and III corps. Thus the 2nd Infantry Division before the end of December was committed on the mountainous central front, surrounded by ROK units on either flank, and charged with the main responsibility of stopping an enemy thrust southward through the central mountains, which the Eighth Army now feared was about to take place.
Chungju was 40 air miles south of Wonju. Supply of the division was difficult. It had to truck all its gasoline 90 miles from Kumchon to Chungju over a route that included a six-mile-long mountain pass. The division requested Eighth Army to establish a Class I, II, and V supply point and an ammunition supply point at Wonju. The closest Class V supply points were at Taejon and Taegu, prohibitive distances away.
While the 2nd Division had been taking in several thousand replacements and reequipping, it had also been engaged in an intensive training program for all its combat units, most of them now having a considerable proportion of replacements. This training tried to profit from the recent combat experiences with the Chinese. It emphasized night-combat problems such as fire discipline and premature exposure of defense positions, which had been costly to it in late November and early December. The training emphasized holding a position during the night at all costs rather than withdrawing in darkness, for daylight would bring help from air and armor. Sleeping bags were not to be used in front-line positions. Warming fires were prohibited there. A minimum ofequipment was to be carried, but having a basic load of ammunition was high priority, and a good supply of hand grenades was emphasized. Care of feet to avoid frostbite was given special attention. Long marches had been frequent in order to inure the troops to fatigue."
Eighth Army Defense Preparations
The American divisions of X Corps were taken by sea to the Pusan area and unloaded there near the end of December. It was evident that the X Corps could not get into the new Eighth Army line and be of practical help until January 1951, at the earliest. For this reason, Eighth Army sent the 2nd Infantry Division to the central mountains at the end of the third week of December to bolster the ROK troops there in the event of an enemy attack down the central corridor toward Pusan.
Definite planning to join X Corps with Eighth Army in South Korea took official form on 6 December, however, when Brig. Gen. Edwin K. Wright, Far East Command Army G-3 operations officer, recommended to General MacArthur that he move the X Corps to South Korea and place it under Eighth Army command. MacArthur approved the recommendation the next day, even though he had some reluctance in placing General Almond under General Walker's command. When General MacArthur discussed his intention to join X Corps with Eighth Army with General Almond, he gave Almond the choice of coming under Walker's command as a part of Eighth Army, or of rejoining the Far East Command as chief of staff, which Almond still was on paper. Almond unhesitatingly said he preferred to remain in command of X Corps under Walker's command.`' General MacArthur notified both Walker and Almond on 7 December of his intention, but he did not then specify the effective date. The Joint Chiefs of Staff in Washington approved the proposal on 8 December.
On 16 December, Eighth Army sent the X Corps a letter outlining the mission it expected to assign it after the corps had assembled in the Pusan area and had reorganized and reequipped under the 2nd Logistical Command in Pusan. It would go into the army line cast of IX Corps and assume an active combat role at the earliest possible date. Three days later, Eighth Army sent IX Corps its top secret plan to use the 2nd Infantry Division in the Wonju area. The next day the army ordered the 2nd Division to move there without delay.
The 1st Marine Division was the first of X Corps's combat divisions to arrive in South Korea. It opened its CP in an old assembly area near Masan on 16 December, and by 17 December, all units were at Masan. The 7th Infantry Division debarked at Pusan on 22 December and moved at once to Yongchon, north of Pusan and on the lateral road between Pohang-dong and Taegu. Its advance party had been there for more than a week, and the 31st Infantry Regiment was already there. The X Corps Headquarters and the 3rd Infantry Division arrived in the Ulsan area during the last week of December. In the meantime, Eighth Army ordered its I and IX corps on 20 December to select and organize a bridgehead line north of the Han River and the Seoul bridges. This line passed in the vicinity of Uijongbu and then turned south toward the Han River.`9
At the same time Eighth Army was going into its defense positions along the Imjin River line north of Seoul and the Han River, it was also moving all supply points south of the river and clearing out the large accumulation of military supplies at Inchon and Ascom City, four miles cast of the port. To naval authorities, Eighth Army indicated that Inchon might have to be evacuated before X Corps had cleared from Hungnam, where most of the available shipping had concentrated. Admiral Joy asked MacArthur to order shipping to be worked 24-hours a day. Inchon had a capacity of loading 3,000 tons daily. Ascom City, on the main road to Yongdong-po and Seoul, had become the main storage center of supplies brought in through Inchon. And at Yongdong-po, on the south side of the Han, railcars were held fully loaded so that they could be hur tied south at a moment's notice. Evacuation of supplies from the Scoul-Inchon area went forward during December by both rail and sea. By 18 December all critical supply materials had been moved from Ascom City, and two days later the 3rd Logistical Command (Inchon) reported that only an Eighth Army Engineering staff remained there. All ammunition supply points had moved south of the Han River. On 12 December ASP 23 at Kaesong closed, and two days later ASP 26 at Munsan-ni, on the south side of the Imjin River, closed.50
As early as 13 Decem
ber Eighth Army and IX Corps had plans in readiness to evacuate Seoul if enemy pressure should dictate a withdrawal south of the Han River. On that date, IX Corps Operational Plan No. 4 called for the 24th Infantry Division to cover the withdrawal through and from the Seoul area. On 20 December IX Corps Operational Plan No. 5 extended some features of Plan 4 and called for the removal or destruction of the Han River bridges in the Seoul area. The British 27th Brigade (minus one infantry battalion), the 6th Medium Tank Battalion, and the 19th Engineer Combat Battalion, under a unified task-force commander, would constitute the covering force for the withdrawal. The next day 24th Division Instruction No. 81 gave the details of the withdrawal and covering force plans and the details of the march order. The 24th Infantry Division was on line in the Uijongbu area almost directly north of Seoul. The withdrawal plan called for the movement to end in the Suwon area, about 25 miles south of Seoul. On 22 December, IX Corps made minor changes in its 20 December Operations Order No. 5.1'
Plans for withdrawal south of the Han River to the Suwon area, however, did not stop there. Defense lines were laid out for the withdrawal of Eighth Army all the way to Pusan, at the southern tip of the peninsula, and the possible withdrawal of the army through that port from Korea to Japan. On 10 December Eighth Army commented on these plans in its command report: "Enemy slow in his follow-up, but even so, the enemy, with so overwhelming a force as he had at his disposal, could not be decisively stopped with the forces available to EUSAK on any defensive line it might establish ... planning contemplated continued withdrawal to successive defensive lines until (if necessary) a final line was reached covering the army's withdrawal from Korea!'"
The successive defensive lines Eighth Army referred to had already been located and defined. They were four in number, named from north to south.
The Naktong line, similar to the defense line of that name, used in the summer (4 Aug.-16 Sept. 1950) to defend Pusan from the North Koreans
The Davidson line-68-mile perimeter
The Raider line-48-mile perimeter
The Pusan line-28-mile perimeter
The Davidson line, given priority in construction, had been partially completed in August 1950, in preparation for a possible forced withdrawal from the Naktong River line in defense of Pusan. This line was named for then Brig. Gen. Garrison H. Davidson, assistant division commander, 24th Infantry Division, and an Engineer officer, who was in charge of laying out the successive defense lines.
The 2nd Logistical Command, headquarters at Pusan, received orders from Eighth Army to complete these four lines. Part of the construction work on the Davidson line called for building a lateral road behind the line, from Miryang in the west to Ulsan on the east coast. The 44th Engineer Battalion, with X Corps, on its arrival in South Korea, was to supervise the construction of the road. The commanding general of the 2nd Logistical Command was ordered to utilize Korean labor in carrying the work forward. Instructions for the defense lines included the following:
1. Double fox-hole shelters for combat personnel and crew served weapons.
2. Clear necessary fields of fire in front of the lines.
3. Install tactical and protective wire.
4. Make plans for mine fields and stock mines where they could be obtained and laid quickly."
On 16 December the 2nd Logistical Command issued Operational Plan "Stop Gap," which required the command to organize four provisional battalions from its service troops (two of them composed of American personnel and two of them from ROK personnel) that could be used in a defense mission, on Eighth Army order, to reinforce and plug gaps in the army's main line of resistance if enemy forces should penetrate them. The 2nd Logistical Command completed the organization of these four battalions during December."`
At the beginning of December, General Walker had a number of defense fines on paper to defend in North Korea and, if necessary, south of the Han River as long as possible, pursuant to General MacArthur's orders to him. These lines were labeled alphabetically from north to south:
Line Able-north of Pyongyang
Line Baker-along the lower Imjin River and then eastward along the 38th Parallel generally
Line Charlie-a crescent around Seoul and east of Hongchon and on to the east coast
Line Dog-below the Han River, from Pyongtaek to Wonju to Samchok on the east coast
If forced south of Line Dog by the middle of December, there were the four final defense lines already mentioned reaching down to Pusan.
As events developed, Eighth Army in December retreated all the way to Line Baker, the Imjin River line, before it stopped to take up a defensive position. This was a retreat of 120 miles before it stopped to see what the CCF would do. Eighth Army was in this line by the middle of December, with a scramble continuing to nearly the end of the month to move ROK divisions into the central and eastern parts of the line.
Line Baker tried to take advantage of the lower Imjin and Han River barriers in the west; in the central part it had the numerous southand southwestflowing tributaries of the Han River as enemy corridors of advance to deal with in uneven and difficult terrain. In the east it had the high divide of the Taebeck Range, only 30 miles on average from the east coast, and mountainous terrain from it sloping down eastward to the Sea of Japan. It was the first attempt of the UN forces to establish a defense line across the breadth of Korea above Seoul. It extended about 135 miles.
The western end of the line was in the low-lying ground of the west coastal and estuary regions of the lower Imjin and Han rivers. Water barriers there made defense fairly easy. Eastward, the southand southwest-flowing tributaries of the Han River made it all downhill for the enemy in approaching Seoul from central Korea by several corridors leading into the Han valley. The main roads followed these tributary streams, and once in the Han valley, a main road followed it west to Seoul. The main enemy corridors of advance toward Eighth Army defense lines were, from west to cast:
1. from Kaesong and Munsan-ni, southeast to Seoul
2. from Chorwon, almost due south through Uijongbu to Seoul
3. from Kumhwa, southwest to Uijongbu, where this corridor joined that from Chorwon
4. from Kumhwa and Hwachon southeast to Chunchon in the Pukhan River valley and then to the Han River valley and hence west to Seoul, or from Chunchon south through the central mountains to Hoengsong and Wonju; from there several possible routes lead to the rear of Eighth Army, allowing enemy to outflank it from the east or drive on south toward Pusan
East of Wonju there was no feasible north-south corridor other than the east coastal road. A study of the terrain indicated that securing Seoul from attack was feasible on the north and northeast only if the Han valley and its tributary corridors could be defended and blocked to enemy advance. Otherwise, enemy forces could outflank Seoul on the east.
On Line Baker's main line of resistance, Eighth Army had ten divisions; two American and eight ROK. A third American division, the 1st Cavalry, was in reserve near Kapyong in the Pukhan River valley, west of Chunchon. The divisions and attached units were on the main line of resistance from west to cast in the following order:
In Eighth Army reserve there were the following major units:
Actually, the US 2nd Infantry Division was moved just back of the main line of resistance on 22-23 December behind the ROK 5th Division in the Wonju area and could actually be considered as part of the main line of resistance. The Baker Line as taken up by the UN forces curved northeast from north of Inchon and the mouth of the Imjin River up the Imjin River to Munsan-ni, on to Yongpyong, and hence cast to pass just north of Chunchon. It then continued on an irregular line northeast, passing just below Inje and hence northeast through the mountains to reach the east coast a few miles north of Yangyang-a total distance of 135 to 140 miles."
The prepared defenses varied greatly over the extent of Line Baker. Most of the ROK divisions in the center and in the east had little more than their individual foxholes and some gun emplacements. In the w
estern part of the line, above Seoul, and particularly in those sectors held by American divisions, the prepared defenses were formidable. These were the sectors held by the 24th and 25th infantry divisions. There the pontoon bridges over the Imjin River on the MSR in the 25th Division sector were removed on 14 December. The next day the infantry troops on the north bank that had protected the engineers in this work crossed to the south side of the river and took up their defense positions. I Corps reported that all M-4 floating bridges (pontoons) had been removed at 3 A.M. on 15 December, and that all UN troops were on the south side of the river. These bridges were salvaged, not destroyed.
Between 16 and 23 December the 25th Division in this vital area placed barbed wire, antipersonnel mines, and flares in front of their positions. Some rifle companies had as many as 14 machine guns emplaced. One battalion front used 800 rolls of barbed wire, 950 flares, and 400 antipersonnel mines on its part of the line.-"'
In the period between 17 and 22 December the Eighth Army G-2 concluded that, if the enemy crossed the 38th Parallel, they would make their main effort down the Uijongbu-Seoul axis; that a secondary advance would be made south on the Hongchon-Wonju axis; and that a deep envelopment of the army and Seoul might be attempted from the Inje area.57
Disaster in Korea Page 60