The undeclared war of Communist China against United Nations forces resulted in major changes in high-level policy and strategy that affected military tactics for the rest of the war. In an attempt to prevent escalation of Korean hostilities into an all-out nuclear war, the decision was made that U.N. forces, both ground and air, would not strike enemy bases in Chinese territory. After the beginning of truce negotiations in July 1951, the mission of Allied ground forces was changed from initiating offensive operations to one of maintaining an active defense of the MLR across Korea. The basic strategy became one of containment and prevention of any further enemy gains south of the 38th Parallel. It involved attempting to inflict maximum losses on the enemy while attempting to minimize those of the UNC. Militarily, these restrictions removed the possibility of winning a decisive victory. For the next two years, fighting seesawed back and forth across the parallel.

Static and defensive warfare thus characterized the greater part of the Korean War. During this period, the Marine division performed a land war mission similar to other Eighth Army components while Marine aviation squadrons flew under control of Fifth Air Force. Both the 1st Marine Division and 1st Marine Aircraft Wing faced tactical restrictions that resulted from the strategic policies governing the overall role of EUSAK and FAF. Problem areas arose from the limited nature of this particular war. These involved not only the shift in the UNC strategy from an offensive posture to a defensive (“active defense”) concept, but also from the paralyzing effect of the protracted truce negotiations on battlefield tactics.

For nearly two years (16 months in West Korea and 5 months earlier while in IX Corps on the East-Central front), the Marine division assumed an unaccustomed defensive role. Such a sustained, basically non-win position was hardly morale-building to the average Marine unable to see personally any yardage gained, any progress made in his particular war. Not surprisingly, such a passive battle assignment did result in a temporary loss of amphibious skills on the part of both individual Marines and the division. End-of-war evaluations noted that “long and indecisive defensive situations such as existed in Korea do little to foster the offensive spirit so long traditional with the Marine Corps and certainly tend to detract from the immediate amphibious readiness required of a Marine Division.”733

Prior to its tour of duty as I Corps reserve in mid-1953, the 1st Marine Division had noted that it would “require intensive training and reequipping for a period of at least 60 days” upon release from active combat in order to “reach a desirable standard of amphibious readiness.”734 Rigorous MARLEX and RCT exercises initiated in June 1952 after the division had moved to the western coastal sector off the Yellow Sea and expanded during its I Corps reserve period, were important steps in rectifying this skill attrition. This was, of course, in addition to the continuous training schedule in offensive and defensive warfare maintained by the division for the battalions and regiment periodically in regular reserve status.

Outpost warfare in West Korea was characterized by overextended MLR frontage. The more than 60,000 yards held by the division while in the I Corps sector resulted in a thinly-held line which invited penetration and encirclement. “Normal” frontage for an infantry division in defense with two regiments on line was considered by U.S. Army doctrine to be 8–9,000 yards. Even with four MLR regiments (two Marine, 1st KMC/RCT, and KPR) and the 1st Amphibian Tractor Battalion on line (the third Marine regiment in reserve with a counterattack mission), this was a very lengthy sector. It was further complicated by the Han River obstacle on the left flank and the Imjin River to the rear of the sector that separated Marine frontline troops from rear support and reserve units.

Infantry battalions thus occupied “extremely wide fronts, as a rule 3,500 to 5,000 yards,” while individual rifle companies were assigned anywhere from “1,200 to 1,700 yards of the MLR to occupy and defend.”735 Prior to the battle of the Hook in October 1952, one of the major engagements on the western front, the 7th Marines at the far right end of the division sector had emplaced all three battalions on line, rather than the customary procedure of two on line and the third in reserve. There was little other choice, for the regimental sector exceeded 10,000 yards, “more properly the frontage for a division rather than a regiment.”736

During a 100 percent watch, at least theoretically, a Marine could be spaced at intervals about every 10 to 15 yards along the MLR. A night 50 percent watch—with personnel of rifle platoons assigned to COPs, listening posts, combat patrols, repair of fortifications, and the KSC nightly supply trains—not infrequently spread personnel to a point where the MLR was dangerously thin, often with 50 yards between men.737 Such an over-wide lineal deployment dissipated defensive strength and made mutually supporting fires difficult.

Division artillery, too, was thinly positioned across the wide sector, making it difficult to execute counterbattery missions. This led to development of the innovative counter-counterbattery program (or “roving guns”) devised by the 11th Marines in May 1952 to deliberately mislead the CCF as to the strength and location of divisional artillery; the situation resulted as well in the reinforcement of the four Marine artillery battalions by heavier I Corps 155mm and 8-inch howitzers. The static situation in the prolonged land campaign also led to the growth of large, semi-permanent type camps which somewhat hampered traditional Marine mobility. Organizations had additional personnel and equipment above T/O and T/E because of the peculiar defense requirements of the sustained battle situation.

The lack of depth in the defense did not provide for receiving the shock of a determined enemy attack, particularly since the normal OPLR had been withdrawn to strengthen the overextended MLR in April 1952, shortly after the division’s arrival in West Korea. Ultimately, as we have seen, this main line of resistance concept was modified and rather than a long thin trenchline the Marine division employed a defense-in-depth concept using a series of strongpoints, as in Boulder City and the organization of the postwar main battle position. In contrast to the Marine situation (and that of most other divisions in the EUSAK line), the CCF confronting the 1st Marine Division beyond No-Man’s-Land deployed their forces in great depth, boasted unlimited manpower, and employed an elastic type of defense on mutually supporting key terrain features. The enemy had also developed an artillery capability that was numerically superior to ours. And they held high ground positions that overlooked virtually the entire Marine front.

As in World War II, Korean operations provided another instance in which various military services and components were coordinated by joint commands: EUSAK for the ground defense and FAF for air. These massive operational command structures accomplished the desired goals. On lower level echelons, however, some policies tended to be so restrictive that they precluded normal combat initiative and aggressiveness. The net result was thus to allow the enemy to maintain the tactical initiative while, in effect, hampering UNC counter-defense measures.

New directives issued by I Corps in late 1952, for example, changed the corps policy of large-scale raids for prisoners, previously encouraged in the spring of 1952, which affected infantry raids and patrol activities for the rest of the war. Plans for all raids, company size or larger, required both I Corps and EUSAK approval, and were to be submitted 10 days prior to planned execution. Complete patrol plans for even platoon-size operations had to be submitted at least 24 hours in advance. Although the reason for the new policy stemmed from a desire to minimize casualties during the prolonged stalemate, negative effects of such a lead-time factor were quickly apparent. Battalion or regimental commanders frequently were unable to capitalize on targets of opportunity that developed or changes in local conditions, such as weather or troop deployment, to gain maximum effectiveness from the operation.

Directives covering offensive maneuvers that could be taken on local initiative were so restrictive that “any independent action below the level of the Division Commander became practically nonexistent.”738 Similarly, counterattack plans to retake previously considered major COPs were countermanded, on several occasions, by corps or army higher echelons shortly before jump-off time with the reason given that the action was not worth the cost of further UNC casualties or possible jeopardy to the fragile peace negotiations.

Allied offensive capability was further restricted by various EUSAK and I Corps orders issued during the protracted period of truce talks. Many directives had as their well-intentioned rationale the desire not to upset the precarious balance in UNC-Communist negotiations by providing the enemy further opportunities for exploitative propaganda victories. The actual record shows, however, that the Communists were never at a loss to conjure up and capitalize on fabricated “events” that suited their purpose—whether charging UNC aircraft had violated the Kaesong neutrality strip, that American fliers were engaging in germ warfare, or deliberately instigating POW camp disruptions and breakouts.

Neutrality restrictions739 on supporting arms within the entire Kaesong-Panmunjom-Munsan-ni area further complicated the UNC tactical situation and hampered both offensive and defensive operations of the 1st Marine Division. This was particularly true of the center Marine regimental sector which was bisected by the Panmunjom corridor and the no-fire lines. The truce talk neutral zone restrictions prevented the Marines in this area from massing their artillery fires on a desirable scale and also, at times, interfered with proper CAS delivery forward of the MLR. The numerous and sometimes conflicting “no-fly, no-fire” restricting lines stemmed from original agreements made between UNC and Communist representatives in 1951. Subsequently, however, the prohibitions against firing any type of weapon in the area were modified from time to time and added to by FAF, EUSAK, and I Corps, “each time adding to the frustration of the local commanders.”740

The double-standard effect of the neutrality restrictions became readily apparent, however. The CCF artfully used this area, by means of his tactics of “creeping” toward the Allied MLR, as a supply and reserve buildup location. The enemy emplaced artillery, assembled troops, and even used the neutral territory for equipment buildups, including tanks, in the Kaesong vicinity.741 Thus the restrictive lines gave the enemy an opportunity to maneuver within an approximate 12 square-mile area, all within effective artillery range and outside of the Kaesong-Panmunjom restricted territory, but UNC units were powerless to take any action.

Intelligence operations, during the latter stages of the war, were not considered optimum—for either the division or wing. While dug in on the western end of I Corps, the Marine information effort had been “seriously hampered by the lack of prisoners of war.”742 Only 94 CCF had been captured by the division during the period, compared with more than 2,000 prisoners taken earlier on the East-Central front.743 This deficiency was attributed to the “static defensive situation, the reluctance of the Chinese to surrender and the heavy volume of fire placed on our reconnaissance patrols.”744

In the air, photo reconnaissance results were not rated entirely satisfactory as a source of current information by either air or ground Marines. The command channels in effect designated the Air Force as responsible agent for control and coordination of all photo missions in Korea. Requests for photographic missions thus were relayed on to FAF and flown by its Reconnaissance Wing or the Marines’ own VMJ-1 squadron. The system produced relatively good vertical coverage with photos available in about 10 days. Special requests for immediate coverage on areas of local importance, however, customarily were either not flown or “delayed to the point where they were of no value”745 because the tactical situation had been changed.

Delays were due to the shortage of photographic aircraft throughout FAF and the limited provision in T/Os for photo interpretation. Intelligence of air-strike targets (particularly post-strike) was consistently mediocre. Oblique photos of frontline positions took an average of three-four days to be processed and sometimes longer. As an expedient, aerial observers began to shoot their own vertical and oblique photos with hand-held cameras slung over the side of a VMO-6 plane.

Probably the most serious problem of all, from the Marine Corps point of view, was that during much of the Korean War Marine air-ground components, trained to work as a team, were to a large extent precluded from operating together. The separate missions of the wing and division reflected, on a smaller scale, the divergent UNC air and ground doctrine and tactics. After the early moving battles, Korean hostilities had settled down to a protracted land war in which ground and air tactical commands did not operate jointly and were never coordinated to deal a truly devastating blow to the enemy. Since the Korean War was a limited one most of the fighting was confined to the stabilized front across Korea. Both air and naval forces were viewed largely as supporting arms for the ground operation.

Due to political-military considerations, UNC tactical air power had been, in effect, handcuffed so that its use would not appear “overly aggressive” and threaten an enlargement of the Korean hostilities into a nuclear armageddon of World War III.746 Since the earliest days of the war, a strict embargo had been placed on any bombing of Chinese rear supply areas or industrial complexes although it was obvious that much of the enemy’s logistical strength lay beyond the Manchurian border.

Air efforts were concentrated largely on nuisance or harassing raids within North Korea and close air support efforts of various types, rather than a systematic destruction of the enemy’s primary supply installation’s. Some ranking officers had informally interpreted official Washington policy as “Don’t employ airpower so that the enemy will get mad and won’t sign the armistice.”747 Indeed, it was not until after the Communists had rejected what the UNC called its “final truce package,” in April 1952, that it was decided to exert greater pressure against the Communists. The list of approved aerial targets was then enlarged to include North Korean hydroelectric power facilities, previously exempted from air attack.

From late 1950 until early 1953, Marine air squadrons were assigned directly by FAF, with CG, 1st MAW, having virtually no tactical control over his own units. Marine Corps aerial doctrine traditionally employed close air support of ground operations as the primary role of its air arm. FEAF and FAF, however, in their interpretation of employment of tactical air power directed FAF maximum efforts toward interdiction missions, sometimes even to the expense of immediate CAS needs.748 As Far East Air Forces stated late in 1951, “when required, close air support of United Nations Army forces may take precedence over other FEAF programs.”749 Interdiction, general support, and close support missions were the normal order of priorities flown by FEAF-FAF.

Operation STRANGLE, the 10-month, all-out, air interdiction campaign during 1951–1952 originally had as its objective the destruction of the North Korean road-rail network. The interdiction program had been defined at first as a move to “paralyze enemy transportation in the zone between the railheads at the 39th Parallel and the front lines.”750 and later somewhat more conservatively as a measure to so “disrupt the enemy’s lines of communication ... that he will be unable to contain a determined offensive by friendly forces ... or to mount a sustained offensive himself.”751

Despite more than 87,552 interdiction sorties flown during the period, CinCFE daily intelligence summaries showed that aerial harassment of the CCF had not hindered their defensive efforts. Instead, by the summer of 1952 the enemy had “actually doubled in troop strength, reinforced their artillery strength to equal that of the UN forces, developed a tremendous AA capability, and established the capability for launching a general offensive.”752 With UNC air and sea superiority, the Chinese Communists had still succeeded in keeping their main supply route open. Rail track cuts were being repaired in as little as 36 hours. And the CCF was employing more fire power than ever: in May 1952, some 102,000 rounds fell against UNC positions compared to only 8,000 the previous July.

Even the retiring UNC Supreme Commander, General Ridgway, admitted before Congressional representatives in 1952 that the enemy had greater offensive potential than ever before, and the Commander, Seventh Fleet, Vice Admiral Joseph J. Clark, declared flatly: “The interdiction program was a failure ... It did not interdict.”753 USAF spokesmen felt it had attained its limited purpose but opined: “Seen abstractly, the United Nations railway-interdiction campaign was defensive and preventive rather than offensive and positive.”754 In early 1952, CG, FAF, General Everest, recognizing that his pilots “had been so long engaged in interdiction attacks that they were losing their skills in close support”755 inaugurated a new system. Beginning in March all fighter-bomber squadrons were to be rotated on weekly close-support missions.

Actually, the skies had begun to clear for Marine aviation operational difficulties by the latter half of 1952. A better understanding had developed between both high-level officials and the working day-to-day liaison operations at JOC CG, 1st MAW had “established his position so firmly he was able to guide establishment of the policies which governed his operations merely by expressing his desires to CG 5th AF.”756 The battle for Bunker Hill in August 1952 had marked excellent cooperation between Eighth Army and FAF, with the 1st Marine Division receiving air priority for two days. In any event, matters were substantially improved from late 1951-early 1952 when, during a 12-month period, 1st MAW CAS sorties for 1st MarDiv had plummeted to the incredibly low figure of 1,956757 or 15.8 percent of the wing’s total 12,372 CAS sorties during FY 1952 (1Jul51–30Jun52).

Commenting on this unhappy period for both air and infantry Marines, Lieutenant General Richard C. Mangrum, USMC (Retired), who was CO, MAG-12 during part of the STRANGLE operations, said “for the rest of 1951 and well into 1952 the major effort of my Group and of MAG-33 was devoted to cutting the rail lines in North Korea. Without success, of course. Little by little we were able to increase the percentages of effort devoted to close support of the troops.”758 And by the last six months of the war the bulk of all CAS missions received by the division were flown by 1st MAW aircraft, in contrast to earlier periods when a third or half of the division’s sorties were Marine-flown. As the last Korean War Wing CG noted, despite basic differences between Army-Air Force and Marine Corps-Navy concept and tactics, ultimately “the commanders of the Fifth Air Force in actual daily practice decentralized control to a marked degree.”759

Throughout the war, however, a lack of standardized terms and differences in request procedures continued to exist. (This was resolved by using Marine control procedures when flying for the division, and Army-Air Force procedures when scrambled on flights for other divisions.) Whereas EUSAK-FAF considered strikes inside the bombline760 as “close air support” and those outside it as “general support,” the Marine CAS concept was one of support in close proximity to frontlines (ranging from 50 to 500 yards out) that affects the fire and maneuver of those ground units. In the hands of Marine FACs, Marine planes employed on close support strikes had a definite influence on the MLR tactical situation.

Then, too, the Marine system of maintaining aircraft “on air alert” resulted in CAS requests being filled in 5 to 15 minutes. Air support requests screened in the regular manner by Eighth Army and FAF at the JOC level resulted in a delivery of ordnance to the target in a minimum of 30 minutes and delays sometimes of nearly four hours.761 During fluid situations, when the division required more than 40 sorties per day, the “on station” system proved more tactically effective than the FAF pre-planned “on call” procedure.

Operational differences between the Marine-Navy and Army-Air Force type of CAS in a critical ground situation were never more apparent than in a major CCF last-ditch effort when the enemy slammed against ROK defenses in the Kumsong area. An end-of-war report noted:

Despite the accommodation reached during the Korean War, many of these fundamental differences in doctrine and employment of air support to ground troops in combat persisted until recent years.763

As military history has shown countless times in the past, wars are fought under the prevailing difficulties of the time. There never was a war waged under ideal conditions. A reflection on operational problems of the Korean period is predicated on the thought that a review of them—and the solutions effected where possible—may help avoid their repetition in a conflict of the future.

Korean Lessons764

In the early phase of the Korean War, the 1st Marine Division deployment was in a moving battle situation similar to numerous engagements it had fought in the past 175 years. Most of the “lessons” learned from the enemy, the tactical situation itself, and the terrain in Korea are derived largely from the later outpost warfare stage when the Marines were employed in a stabilized and sustained defensive situation similar to that facing other Allied units across the entire Eighth Army front. Tactics of defense on a wide front, construction of permanent type field fortifications, and organization of the battle position in difficult terrain was a new experience to Marines. This period of limited objective attacks and battles of attrition highlighted the importance of small unit tactics and demonstrated some modified concepts regarding employment of supporting arms.

During the period of outpost warfare, the 1st Marine Division was never confronted by a general enemy offensive or combined infantry-armor-artillery-air assault. The nature of the conflict was one of limited objective attacks, with strong and sometimes sustained probes. Typically, these were two-battalion assaults against a platoon-size outpost.

Time after time, as UNC defending troops learned, the CCF characteristic pattern of attack was repetitive and almost predictable. After dark, heavy preparatory fires deluged an isolated advance outpost. Crude, but effective, improvised demolitions often reduced COP fortifications765 so that the enemy could assail the position. Waves of attacking Chinese then overwhelmed the greatly outnumbered defenders. Almost invariably the initial attack made on the front of the position was a feint; the real attack would be made by troops that had enveloped the position and moved to the rear. Enemy ambush forces were also located to the rear of the outpost, between the COP and MLR, at normal reinforcement routes to prevent both a pullback by the defenders to the MLR and to stop reinforcements from reaching the outpost.

Effective defensive fire plans for the COPs covered all likely enemy approaches and assembly areas, as well as close-in boxing fires of the COP on all sides. Marine defense positions were sited for all-round defense, with special attention paid to covering the rear approaches at night. This tactic of rear envelopment also applied on a smaller scale to patrols. Invariably the CCF maneuvered to the flanks and rear of a friendly patrol in an attempt to encircle it. The CCF skillfully employed both the terrain and troops and regularly attacked from more than one direction.

Experience with Communist combat techniques forced UNC leaders to reevaluate their own night-fighting tactics. The Chinese had a marked superiority in night operations. Every major attack on Marine outposts during the last year of the war was made at night. When they were not directly assaulting a friendly site, the CCF advanced their own ground positions by digging and their well-known creeping tactics. This enabled them to establish an OP line within small arms and mortar range of Marine COPs and the MLR. The battle for Bunker Hill came about as a result of this enemy tactic. Organization in early 1952 of COP-2A, adjacent to the Panmunjom corridor, was in direct rebuttal to this same tactic. By such indirect methods, the Chinese were further able to extend their already favorable high ground positions which gave them observation over practically all of the Marine front line. Defensively the enemy used the cover of darkness equally well: mountain roads were aswarm with trucks and supply movements, which UNC night-fighters and bombers slowed with only moderate success.

Skilled, rapid construction of field fortifications and excellent camouflage discipline by the enemy were also object lessons. Entrances to tunnels and caves, as well as the bunkers themselves were so carefully disguised by fresh branches, weeds, logs, and other natural foliage that they were rarely visible either by air observer or aerial photographs. Active weapons positions were also effectively camouflaged. Often 60mm and 82mm mortars were housed in bunkers and fired through a narrow opening at the top. If moved out temporarily to an open slope, they were quickly returned to the bunker to avoid detection. The Chinese elaborate underground system of trenchworks and radial tunnels between forward and rear bunkers was sometimes as much as 35 yards long. Underground bunkers and tunnels often had 20 feet or more of protective dirt cover and offered security from anything except a direct aerial hit.

Destruction of the enemy’s trenches, bunkers, and cave network by medium and heavy artillery was only partially successful. Napalm was generally ineffective due to the lack of combustible materials in CCF ground defenses. The well-prepared, deeply dug fortifications were virtually impervious to anything less than air assaults with heavy ordnance (1,000-pound bombs and over) which were required to destroy CCF reverse slope positions.

A well dug-in secondary line was located four to eight miles to the rear of the Chinese MLR. Intelligence indicated that an attack to infiltrate CCF defenses would “require the penetration of a fortified area to a minimum depth of 10 miles.”766 Some Korean War analysts maintained that behind their front line the Chinese had entrenched the ridges to an average depth of 14 miles and that the enemy “could have fallen back upon successive prepared positions for all that distance.”767 Although the trench warfare period of the Korean War was often likened to World War I, the Chinese defensive works were estimated to have “ten times the depth of any belt of entrenchments in World War I.”768 Some areas had even been engineered for defense against nuclear attack. Caves, tunnels, and particularly reverse slope positions also showed CCF skill in the selection and organization of terrain features.