Coalition combat: supporting South Korean forces.

From 1950 to 1953, with only a partial mobilization, the Army fought in Korea, bolstered its presence in Europe, and organized an air defense artillery system on the homefront. Success in these endeavors depended significantly on the capability of the Republic of Korea (ROK) army to stand and fight. Firepower, particularly field artillery, was an advantage that U.N. forces enjoyed during the war. Because the Koreans were lacking in artillery, American units were frequently tasked for support. U.S. artillerymen had inadequate doctrine, combined operations training, and equipment. Moreover, they had to overcome differences in language, culture, and skill levels, and also fears that the Koreans would collapse when attacked, leaving the artillerymen exposed to enemy infantry.

Efforts to provide field artillery support were successful overall. American gunners often made the difference between victory and failure despite linguistic and cultural barriers even though firepower by itself could not always compensate for the weaknesses of ROK forces. Thus a lot of emphasis was placed on expanding Korean firepower in the last two years of combat, especially field artillery, and improving the skill of the units employing it.

Starved for Support

When the war began in June 1950, the South Koreans had little in the way of field artillery. There were just six battalions, which had only finished initial training in October 1949, to support its eight divisions. The battalions were equipped with 15 light M-3 105mm howitzers, a shorter-range version of the standard howitzer. Ammunition stocks were low. The South operated an artillery school and a few Koreans had attended the U.S. Army Artillery School. American artillerymen had served with the Korean Military Advisory Group (KMAG).

The U.S. field artillery establishment showed the effects of lean postwar budgets. Eighth Army in Japan lacked corps-level support battalions, and division artillery battalions were all short one of their three firing batteries. The General Reserve contained only 11 nondivisional battalions, all short of personnel. The Army National Guard had 32 battalions of nondivisional artillery, all on reduced tables of organization, short of equipment, and needing months of training.

American artillerymen faced other problems. The skills of officers and enlisted men varied considerably. World War II veterans were experienced but were a minority by 1950. Junior enlisted training since 1945 suffered from cuts in initial training and, in many cases, from inadequate unit training. Artillerymen also faced a unique problem, the decision in 1946 to merge field and coast artillery into a single branch. In practice, field and antiaircraft artillery skills had little overlap, so officers trained in one specialty but posted to the other were usually an encumbrance.

Combat in Korea found American artillery unprepared in several areas. Although there was doctrine on mountain operations, units had little training. Moreover, most units were unprepared to defend battery positions and convoys. And finally, there was no guidance on supporting non-U.S. infantry beyond standard teachings on artillery liaison with maneuver units.

ROK artillery performance, like the rest of the Korean army, varied in early engagements. Some units quickly broke while others fought on stubbornly. The surviving units withdrew to the Pusan Perimeter with U.S. forces. In August, reinforcements joined Eighth Army, including firing batteries, bringing division field artillery battalions to full strength and providing separate battalions to serve as corps artillery.

Growing artillery strength and the positioning of American and ROK divisions side by side on the perimeter allowed U.S. artillerymen to shoot in support of Korean units. An early instance occurred when 1st Cavalry Division artillery operated with 1st ROK Division. The American units remained in 1st Cavalry's sector, firing across its right flank, supporting the South Koreans in both attack and defense. Korean forward observers, sending data through 1st Cavalry Division artillery liaison officers, directed most of the firing. The greatest difficulties in these missions were the language barrier and inexperienced Korean observers, who exaggerated mission results. (1)

A Perfect Partnership

The deeds of 1st ROK Division in mid-1950 earned it a good reputation among Americans. On September 18, 10th Antiaircraft Artillery (AAA) Group was attached to 1st ROK Division to act as artillery headquarters. The group brought with it 78th AAA Gun Battalion, with towed 90mm guns, and 9th Field Artillery Battalion, with towed 155mm howitzers.

The headquarters mission presented 10th AAA Group with a problem: although doctrinal manuals included using antiaircraft units as field artillery, it was assumed that they would reinforce the fires of field artillery units, not act as the field artillery headquarters. Colonel William Hennig, USA, the 10th Group commander, found that only a few of his officers knew anything about field artillery operations. Fortunately, Eighth Army had earlier attached 10th Group to 1st Cavalry Division for several days. Hennig had his operations section staff observe the divisional fire direction center. A member of the section later wrote, "the effective operation of 10th Group can be traced to this helping hand." (2)

While together from September to December 1950, 1st ROK Division and 10th AAA Group proved a formidable combination. Their success resulted from a harmonious relationship between their commanders and professional competence, generating mutual respect. The 1st ROK Division commander, Major General Paik Sun Yup, remembered Hennig as a "truly humble officer" who told him that the "job of the artillery and the other combat arms is absolute support of the infantry." According to Paik, "Every time [our] division faced a combat crisis thereafter, Hennig provided every practical cooperation." Paik's energy and leadership from the front impressed the Americans as well. The record of 10th Group noted that he "has gained the personal respect of all personnel."

A consistent obstacle in combined operations was a fear on the part of Americans that they could not rely on the Koreans. However, the competence of 1st ROK Division laid that concern to rest. When Paik presented Hennig a division patch, the group's war diary recorded it as a "signal honor," as the division was a "great fighting force." In return, the eagerness of 10th Group and its subordinate units to support 1st ROK Division impressed the Koreans. Hennig routinely traveled with Paik, and antiaircraft liaison officers moved with division and regimental headquarters and worked with both Korean commanders and KMAG advisors to coordinate fire support. A notable case of American willingness to offer support came in the advance on Pyongyang: group vehicles shuttled Korean infantry forward and M-55 machine gun mounts, placed on trucks, moved with division lead elements to bring tremendous firepower to bear on enemy road blocks.

The climax to the partnership occurred at the Battle of Unsan on October 25 to November 1 and withdrawal from the Chongchon River in late November. At Unsan, as the Chinese checked the drive by the division into North Korea, the battle culminated with an enemy attack on the night of October 31. 78th AAA Battalion, exploiting the 360-degree capability of 90mm guns, fired in three directions, expending 1,319 rounds. With the 4.2 inch mortars of 2d Chemical Battalion and 9th Field Artillery, this fire support enabled 1st ROK Division to repulse the attack. Withdrawing from the Chongchon, 10th Group, reinforced by 68th AAA and 555th Field Artillery Battalions, supported the division as it covered 24th Infantry Division's withdrawal, then withdrew itself south of the river. On December 1, in retreat and increasingly fearful of Chinese and Soviet air attacks, Eighth Army reassigned 10th AAA Group to air defense. Paik later wrote that with the departure of the group, "I felt like the [division's] firepower had shrunk to nothing."

Trial and Error

Most field artillery support for Korean units during the mobile phase was less successful. On February 5, 1951, X Corps mounted an attack north of Wonju with two Korean divisions. Because these divisions still had only one battalion of field artillery, X Corps ordered the American 2d and 7th Infantry Divisions to assist. Supporting 5th ROK Division was 49th Field Artillery of 7th Division, reinforced with a battery of 155mm howitzers, automatic weapons antiaircraft battery, engineer company, infantry battalion, and reconnaissance company of 7th Division. Supporting 8th ROK Division was 15th Field Artillery, reinforced with a battery of 155mm howitzers as well as an automatic weapons antiaircraft battery and an infantry battalion. By this point, Eighth Army had lost so many howitzers that protection of field artillery was paramount; each support force included American antiaircraft weapons and infantry because of concern over Korean reliability. Available to fire reinforcing missions was 96th Field Artillery, a 155mm howitzer battalion.

Operation Roundup support forces had little time to establish a relationship with the Korean divisions; after receiving the mission on the night of February 3, they moved into Korean sectors. The commanders of 15th and 49th Field Artillery met with the division commanders the next day to plan fire support. Forward observers and liaison officers from the battalions only arrived at the infantry regiment level within the division a few hours before the attack began February 5.

While 8th ROK Division advanced on the left, its 20th Field Artillery failed to impress the Americans because of poor shooting. 5th ROK Division hit strong resistance on the right from the start. The commander of 49th Field Artillery assumed the duties of division artillery headquarters; he also had to direct resupply of the artillery battalion with howitzer ammunition. On February 8, artillery fire broke up a North Korean attack on an infantry regiment. Increasing resistance led X Corps to add 674th Field Artillery Battalion in support on the same day. Then on February 10, X Corps moved 5th ROK Division to blocking positions on the right flank and brought up 3d ROK Division to continue the attack with fire support from 49th Field Artillery and its attachments. The battalion sent forward observers and liaison officers to the infantry regiments of 3d ROK and liaison officers to its command post and artillery battalion; 674th Field Artillery remained with 5th ROK.

The communists counterattacked on the night of February 11. Three divisions poured over 8th ROK Division as another Chinese force hit 3d ROK on the right flank and North Korean units attacked 5th ROK Division. All three divisions collapsed by first light. American liaison officers and forward observers with infantry regiments reported the collapse of their field artillery battalions and attempted to move south to safety among the routed South Koreans.

Uncertainty in 2d Infantry Division and X Corps over who held the authority to order the support forces to retreat was a disaster for units with 8th ROK Division. When the commander of 15th Field Artillery got permission to withdraw around 0300 hours on February 12, the Chinese had established strong positions between the support force and 2d Infantry Division at Wonju. The support force, with American and Dutch infantry battalions, had to fight its way back to Wonju. The unit was beaten with the loss of 14 howitzers, 349 enlisted men, and 28 officers, including the battalion commander, executive and operations officers, four liaison officers, two battery commanders, three firing battery executive officers, and most of the forward observers. An attached battery belonging to 503d Field Artillery lost all its 155mm howitzers.

The support force with 3d ROK Division did better. X Corps Artillery informed 49th Field Artillery of the developing situation and gave it a movement warning order. Two and a half hours later, the 49th Field Artillery liaison officer with 23d Infantry Regiment notified his battalion that the Korean infantry was withdrawing in haste. Learning that the Chinese had blocked the road south to Wonju, engineers were ordered to cut a road with bulldozers. The support force reached safety with the loss of only one 155mm howitzer; battalion losses were two killed, thirty-eight wounded, and thirteen missing. Infantrymen in the 5th ROK Division sector withdrew in rout order and one battery was forced to use direct fire on advancing enemy infantry to escape. The battalion was able to withdraw without losing any howitzers.

The Chinese continued to attack on the morning of February 14, seeking to capture Wonju. Unfortunately for them, X Corps had assembled a powerful concentration of field artillery. Eleven infantry battalions--seven American, three Korean, and one Dutch--shielded this concentration. Coordinated by 2d Infantry Division Artillery headquarters, American gunners repulsed the attack, killing some 5,000 Chinese and leaving four divisions combat ineffective. The "Wonju shoot" dramatically demonstrated the power of American field artillery when its infantry shield held firm and the enemy presented a lucrative target.

Building the Fire

In January and February 1951, Eighth Army received sizable field artillery reinforcements, one Reserve and nine National Guard battalions mobilized the previous summer. While these units still left Eighth Army far short of what doctrine and commanders with World War II experience anticipated, they played a key role in defeating the communist offensives in April and May 1951.

Reinforcements also allowed Eighth Army to provide more field artillery support to Korean divisions. Added firepower helped Korean divisions during the enemy spring offensives but could not compensate for inadequate equipment, training, and leadership. An example of the capabilities and limitations of American field artillery support occurred in IX Corps during the April offensive, when 987th and 92d Armored Field Artillery Battalions supported 6th ROK Division.

The Korean division and artillery battalion had not impressed 92d Field Artillery during the previous month; ROK 27th Field Artillery had great difficulty maintaining communications with its forward observers and the division did not know how to exploit the capabilities of a U.S. artillery unit. As IX Corps prepared for an expected communist offensive in April, it attached 987th to 92d Battalion and gave the units a mission to reinforce 27th ROK Field Artillery fires.

Both U.S. battalions provided liaison to 27th ROK Field Artillery, and 987th Field Artillery sent a liaison officer and three observers for the division infantry. Because its 105mm howitzers had a shorter range than the 155mm howitzers in 92d Battalion, 987th Field Artillery had to move further forward in the division sector. The terrain in the 6th ROK Division area made that difficult; to reach assigned positions in the vicinity of Sachang-ni, heavy tracked vehicles had to move over steep hills on a narrow dirt track that crossed several streams. The entire route was subject to cave-ins and landslides. By nightfall on April 22, only nine howitzers had reached the battalion position; the other nine remained in the previous position five miles away as battalion personnel and Korean engineers cleared the road.

The nine howitzers in the new position began firing as soon as registration was completed, as 6th ROK Division came under heavy pressure. Retreating Korean troops appeared in such numbers that the Americans could not prevent them from passing between their guns. To the rear, 92d Field Artillery commander placed an officer and an interpreter on the road to rally the Koreans. The pair collected between 500 and 600 soldiers, who were put under the control of a KMAG officer. By 0900 hours, 987th Battalion liaison officers informed their commander that 2d Infantry Regiment had collapsed and 27th Battalion position had been overrun. The commander of 987th Battalion contacted the 92d Battalion command post for instructions. When none arrived, he ordered his forward batteries to withdraw. However, the road collapsed at a chokepoint, trapping the howitzers, and fire from Chinese on the adjacent high ground forced the cannoneers to abandon their vehicles. A scratch force attempted to recover the guns after dawn, but it was ambushed and withdrew. Marines trying to retrieve the vehicles later in the day were also turned back.

IX Corps ordered the newly arrived 213th Battalion to replace 987th Battalion in support of 6th ROK Division on April 23. This new 105mm howitzer unit moved into position only to find that the Koreans were quickly withdrawing. Returning to their old position, the Americans fired 200 rounds in support of retreating forces. The situation led IX Corps to move 213th Field Artillery the next day to support a harder-pressed unit, but it later returned to fire for 6th ROK Division from April 25 to 27, which the Korean commander cited as the largest factor in breaking the attacks on his division. Then 213th Field Artillery helped cover the withdrawal by 24th Infantry Division.

Finding Common Ground

U.S. officers identified several impediments to cooperation in their analysis of field artillery support. The first was language; 987th Battalion recorded that "good interpreters are a great asset to a unit, particularly when supporting an ROK division." Unfortunately for the battalion, it had received civilian interpreters, and most were "practically worthless under combat conditions."

A second obstacle was the quality of the Korean troops. American artillery units could not overcome the inability of some ROK units to stand and fight, which in turn stripped the artillery of infantry protection. During the May 1951 communist offensive, X Corps dealt with this situation by not placing American battalions in Korean division sectors. Instead, a 155mm howitzer battalion was positioned on the flank of a U.S. division so it could fire into the 5th ROK Division sector, with a liaison team dispatched to the division KMAG detachment. In addition, X Corps Artillery positioned 8-inch howitzers and 155mm guns to support 7th ROK Division without having to enter its sector.

Another facet of the deficiencies in Korean training and experience was a virtual absence of liaison between infantry and artillery units. ROK infantry commanders treated American artillery units in a similar way; 987th Field Artillery was not warned when 2d Infantry Regiment decided to withdraw. U.S. liaison officers discovered that constant close contact with KMAG officers was essential.

A third obstacle was the clash between American field artillery doctrine and the problems of supporting an army lacking in artillery with little experience in combined arms operations. During Chinese spring offensives, U.S. corps artillery headquarters usually gave a reinforcing or general reinforcing mission to field units supporting the Korean units. For American artillerymen, doctrine dictated specific responsibilities in such missions. In a reinforcing mission, the unit "receives calls for fire from the unit whose fires it is to reinforce" and is prepared "to establish command liaison with, and to reinforce the observation of, the unit whose fires it is to reinforce." In a reinforcing mission, the first priority is shooting missions from corps artillery headquarters, and then being prepared to shoot reinforcing missions for a specific subordinate artillery unit of the corps. The reinforcing commander needed to coordinate with the reinforced artillery and put a liaison officer in the unit command post.

After the communist spring offensives, American artillerymen concluded that when supporting Koreans, "it is almost impossible to accomplish a mission of supporting them in the manner to which our training and experience has accustomed us." The weaknesses of equipment, training, and experience in Korean artillery battalions meant that American units had to approach reinforcing them more as a direct support mission. The 987th Battalion recorded, "The efficiency of artillery units in support of ROK units is almost directly proportional to the number of liaison and forward observer parties used. To send your liaison officer to the reinforced ROK field artillery battalion is not sufficient."

This judgment created trouble for corps artillery units. Their organization did not include the personnel and equipment found in divisional direct support battalions to field sufficient liaison and forward observer parties. A corps artillery 105mm battalion was authorized one liaison officer and three forward observers. In April 1951, 213th Battalion fielded four liaison officers and nine observers. In support of 2d ROK Division in May 1951, 987th Field Artillery provided liaison to division headquarters, 18th Field Artillery, and three infantry regiments. Officers, enlisted men, and equipment for these parties were taken from battalion headquarters and firing batteries, creating a corresponding difficulty for them to accomplish their missions.

American field artillery support for Korean units met with mixed results. On occasion, like the destruction of 15th Field Artillery in Operation Roundup, poor teamwork led to a disaster for supporting artillery. In instances when both U.S. and Korean units were competent, had dynamic leadership, and developed a long-term relationship, like the association of 1st ROK Division and 10th Group, the results were equal to or superior to those found on average in U.S. units. These two examples, however, were at the extremes. More typical were the experiences of 92d, 213th, and 987th Battalions in the spring 1951 offensives. During the mobile phase of the war, Eighth Army lacked adequate nondivisional field artillery to develop regular relations, thus American and Korean units had little time to form associations. The absence of skill and experience in Korean units meant that reinforcing missions had to be performed more as direct support by American units, which were ill-equipped for the role. Language and cultural differences were only partially overcome by bringing KMAG advisors into fire support operations.

Finally, U.S. firepower could often, but not always, prevent the collapse or destruction of Korean units which, because of weaknesses in firepower, skill, and leadership, became a focus of enemy offensives. American artillerymen--called upon to conduct missions for which they were unprepared in doctrine, training, and resources--usually persevered, though not without extensive improvisation, hard work, and heavy losses.

Armed Forces of the Republic of Korea

The South Korean military traces its origins to the constabulary unit organized in 1946 to assist the American occupation forces and national police in maintaining public order. When the Republic of Korea was established in 1948, the constabulary served as the core of a nascent armed forces.

Army. The Korean army was formed on December 15, 1948. The U.S. Korean Military Assistance Group (KMAG) was organized on July 1, 1949, replacing provisional detachments that had been training Korean ground forces. By June 1950 the army included eight poorly equipped divisions with 115,000 troops. When the war ended, South Korea had three corps with 590,911 men under arms. Each regiment, division, and corps had a compliment of KMAG advisors.

Navy. The Coast Guard helped in organizing the Korean coast guard in 1946, which became the nucleus of the new coast guard/navy in 1948. During the conflict, South Korean naval forces included frigates, minesweepers, and landing ships which operated under the command of U.S. Naval Forces Far East.

Air Force. South Korea formed its own air force on October 10, 1949. When war broke out, the United States provided ten F-51s to South Korea. Korean pilots flew as part of a composite U.S.-Korean unit organized by U.S. Far East Air Forces during the conflict.

South Korean military losses from 1950 to 1953 totalled 415,000 killed and 429,000 wounded.

NOTES

(1) Roy E. Appleman, South to the Naktong, North to the Yalu (Washington: Office of the Chief of Military History, 1961), pp. 350-61.

(2) Arthur C. Brooks, Jr., "From Pusan to Unsan with the 10th AAA Group," Antiaircraft Journal (January-February 1951), p. 13.

William M. Donnelly is a historian at the U.S. Army Center of Military History and the author of Under Army Orders: The Army National Guard during the Korean War.