The Chinese Appraise Their First Phase Korean Action
Those who wage war in mountains should never pass through defiles without first making themselves masters of the heights.
MAURICE DE SAXE, Reveries on the Art of War
What were the Chinese Communist Forces that fought the battles in late October and early November, and just when and how did they come to Korea? What did they think of their own efforts in their first actions against American troops?
The Chinese troops that appeared suddenly in the Korean fighting near the end of October had crossed the Yalu River from Manchuria in the period from 13 or 14 to 20 October. Hiding from aerial observation during the day and marching at night, they had reached their chosen positions on the southern fringe of the high mountain mass fifty air miles south of the Yalu. There they lay in wait overlooking the corridors that entered these mountains from a point near Huich'on on the east along a line extending sixty air miles westward through Onjong and Unsan.
Three Chinese armies, the 38th, 40th, and 38th, each composed of three infantry divisions, were deployed in that order from Huich'on westward, on this line of battle in front of Eighth Army and the ROK II Corps. The 38th Army was northwest of Huich'on, the 40th in the Onjong area, and the 38th above Unsan. Two more armies, the 66th and the 50th, of three divisions each, remained hidden in reserve and out of action in the west during the Chinese First Phase Offensive. This made a total of fifteen divisions. Elements of another division, the 125th, apparently were the troops that cut off and dispersed the 7th Regiment of the ROK 6th Division below Ch'osan. 
The CCF 38th Army arrived at An-tung on the north side of the Yalu River in Manchuria in mid-October and immediately crossed the river into Korea
 ATIS Enemy Documents, Issue 47, pp. 139ff, booklet, A Collection of Combat Experiences, issued by Hq XIX Army Croup, CCF, 29 Mar 51 (also partially reproduced by Hq U.S. I Corps, G-2 Sec, Aug 5,); Ibid., Issue 11, pp. 74-82, Primary Conclusions of Battle Experiences at Unsan, issued by Hq 66th Army, 20 Nov 50; Ibid., Issues 6, 2 Sep 51, A-9 and 35, 1-15 Nov 52, p. 45; FEC Intel Digest, vol. I, Nr 4, p. 26 (17 Feb 53), XIII Army Group, CCF; FEC, Order of Battle Information, CCF, 15 Jun 51.
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at Sinuiju. There it came under the operational control of the XIII Army Group. The 38th and 40th Armies crossed into Korea about the same time. Later in the month, the 50th and 66th Armies crossed into Korea in support of the others. It may be concluded that if the U.S. I Corps had not withdrawn when it did, elements of these two CCF armies would have engaged the 5th and 19th Regiments of the 24th Division above Kusong. As it was, small parts of the 66th Army did accidentally encounter the 19th Regiment there on 1 November and exchanged shots with it. 
While the CCF 38th Army stopped the ROK 1st Division at Unsan, the 40th engaged and virtually destroyed the ROK 6th Division at Onjong. On the second day of the action, 26 October, the CCF 38th Army joined the 40th Army in the battle against the ROK 6th and 8th Divisions between Onjong and Huich'on. These two Chinese armies then rolled the ROK II Corps back southwest along the valley of the Ch'ongch'on to the edge of Kunu-ri.
Simultaneously with the deployment of these Chinese divisions in front of Eighth Army, others deployed in front of the X Corps in northeast Korea. Three CCF divisions, the 124th, 125th, and 126th, forming the 42d Army, entered Korea at Manp'ojin. The first to cross the border was the 124th Division. On 14 October it left T'ung-hua in southern Manchuria, about fifty air miles from the North Korean border, and proceeded by train to Chi-an on the Yalu opposite Manp'ojin, where it crossed the river the same day. On the 16th it started on foot from Manp'ojin, marching southeast through Kanggye and Yudam-ni to Hagaru-ri. From there its advanced elements proceeded to the point south of the Changjin Reservoir where they met the ROK 26th Regiment on 25 October. The remainder of the division moved up to the point of contact and joined in the battle near Sudong against the U.S. 1st Marine Division troops that replaced the ROK 26th Regiment. The other two CCF divisions that followed the 124th into Korea at Manp'ojin remained out of action behind the 124th in this phase of the fighting, but assumed defensive positions in the Changjin Reservoir area, blocking the roads to Kanggye.
Except for the action against the 124th Division, it would appear that the ROK and U.S. troops had not reached the points in northeast Korea where the CCF intended to block their advance. While the 124th Division at first drove back the ROK troops it encountered, and then slowed the advance of the U.S. Marine troops that replaced them on the road to the reservoir, it did not have the success that attended the CCF action against the ROK II Corps and part of the U.S. I Corps in the west. In fact, this CCF division was virtually destroyed.
In the First Phase Offensive, highly skilled enemy light infantry troops had carried out the Chinese attacks, generally unaided by any weapons larger than mortars. Their attacks had demonstrated that the Chinese were well-trained disciplined fire fighters, and particularly adept at night fighting. They were masters of the art of camouflage.
 FEC Intel Digest, vol. I, Nr 4, 1-15 Feb 53, Histories of CCF Army Groups Active in Korea: XIII Army Group, pp. 30 37; EUSAK PIR log. 29 Oct 50.
CHINESE APPRAISE FIRST PHASE KOREAN ACTION Page 719
Their patrols were remarkably successful in locating the positions of the U.N. forces. They planned their attacks to get in the rear of these forces, cut them off from their escape and supply roads, and then send in frontal and flanking attacks to precipitate the battle. They also employed a tactic which they termed Hachi Shiki, which was a V-formation into which they allowed enemy forces to move; the sides of the V then closed around their enemy while another force moved below the mouth of the V to engage any forces attempting to relieve the trapped unit. Such were the tactics the Chinese used with great success at Onjong, Unsan, and Ch'osan, but with only partial success at Pakch'on and the Ch'ongch'on bridgehead.
The Chinese soldiers engaging in the First Phase Offensive were well-fed, in excellent physical condition, well-clothed, and well-equipped. As the British had noted, some of them even wore fur-lined boots. Despite numerous American intelligence conjectures at the time that the first Chinese were integrated and scattered throughout the North Korean units, this was not the fact. From the very beginning the Chinese fought in Chinese organizations and were never mixed as individuals into North Korean organizations.
In the offensive against the Eighth Army and the ROK II Corps at the end of October and the first week of November the action was almost entirely by Chinese troops. The delaying action along the west coast against the 24th Division, however, was by North Koreans. Only in rare instances, such as in the final action to the east against the 19th Infantry and the 27th British Commonwealth Brigade, were North Korean infantry troops involved, and then they apparently constituted only a relatively small part of the total attacking enemy force. The North Korean 105th Armored Division, partly reconstituted since the Naktong battles, was committed to help the Chinese and did so with tank fire in a few instances, but it played a negligible role in the fighting. The Fifth Air Force destroyed most of its tanks back of the battle front. On 7 November, for instance, U.N. aircraft reportedly destroyed 6 tanks, 3 armored cars, and 45 vehicles in Pakch'on and the area eastward. 
At the same time in northeast Korea the ROK I Corps encountered Chinese forces at only one point on the road to the reservoir. Within a few days elements of the 1st Marine Division relieved the ROK's there, and they had a stubborn fight for nearly a week in gaining the Kot'o-ri plateau south of the Changjin Reservoir. The Chinese intervention in northeast Korea had not been on the same scale as in the west central part, nor had it had the same success. It is to be noted that the Chinese appeared only in the mountainous, inland part of the peninsula; on neither coast were there any Chinese contacts at this time.
Since the First Phase Offensive was the first engagement in the Korean War between American and Chinese troops, the opinion the Chinese formed of their adversary as a result of it may be of interest. On 20 November, less than three weeks after the CCF 38th Army had driven the U.N. forces from the Unsan area, the headquarters of the
 24th Div WD, 7 Nov so; GHQ FEC, History of the N.K. Army, p. 80.
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66th Army, "Chinese Peoples' Volunteer Army," published a pamphlet entitled, "Primary Conclusions of Battle Experiences at Unsan." In it the Chinese listed what they considered the strengths and weaknesses of the American forces, based on their experience with the 8th Cavalry Regiment. On the favorable side the pamphlet described in some detail the American method of making an attack and said:
The coordinated action of mortars and tanks is an important factor.... Their firing instruments are highly powerful. ... Their artillery is very active.... Aircraft strafing and bombing of our transportation have become a great hazard to us . . . their transportation system is great. . . . Their infantry rate of fire is great and the long range of fire is still greater. 
Not so favorable was the Chinese estimate of the American infantry. The pamphlet said that American soldiers when cut off from the rear
. . . abandon all their heavy weapons, leaving them all over the place, and play opossum.... Their infantrymen are weak, afraid to die, and haven't the courage to attack or defend. They depend on their planes, tanks, and artillery. At the same time, they are afraid of our fire power. They will cringe when, if on the advance they hear firing. They are afraid to advance farther.... They specialize in day fighting. They are not familiar with night fighting or hand to hand combat.... If defeated, they have no orderly formation. Without the use of their mortars, they become completely lost. . . they become dazed and completely demoralized.... At Unsan they were surrounded for several days yet they did nothing. They are afraid when the rear is cut off. When transportation comes to a standstill, the infantry loses the will to fight.
After analyzing the Americans' strength and weakness, the Chinese set forth certain principles for future operations:
As a main objective, one of the units must fight its way rapidly around the enemy and cut off their rear.... Route of attack must avoid highways and flat terrain in order to keep tanks and artillery from hindering the attack operations.... Night warfare in mountainous terrain must have a definite plan and liaison between platoon commands. Small leading patrol groups attack and then sound the bugle. A large number will at that time follow in column.
The Chinese admitted they did not have an effective weapon against the American tank, but said that 20-pound TNT charges placed on the tracks or under the tank would disable it. Antitank sections consisted of four men carrying two 20-pound and two 5-pound charges.
The Chinese summed up their viewpoint on the first phase of their intervention:
Our Army [38th] was the first expeditionary force ordered to hurry to the Ung-pong area of Unsan to relieve the North Korean Army and intercept the enemy advancing northwards at Unsan. We deployed our main force to encircle and annihilate the enemy at Hichon [Huichon], Onjong, and Chosan. At that time, we did not fully comprehend the tactical characteristics and combat strength of the enemy, and we lacked experience in mountain warfare. Moreover, we engaged the enemy (first, in the form of interdiction, then in that of attack) without sufficient preparation; yet the result was satisfactory.
 ATIS Enemy Documents, Issue 11, pp. 74-82, reproduces this document, captured by ROK 1st Div, 26 Nov 50. See also ATIS Enemy Documents, Issue 47.