The Korean War: The Outbreak

Cover: Troops of the 1st Cavalry Division in action against North Korean invaders, 25 July 1950.

The Outbreak
27 June-15 September 1950

Strategic Setting



Further Readings


The Korean War was the first major armed clash between Free World and Communist forces, as the so-called Cold War turned hot. The half-century that now separates us from that conflict, however, has dimmed our collective memory. Many Korean War veterans have considered themselves forgotten, their place in history sandwiched between the sheer size of World War II and the fierce controversies of the Vietnam War. The recently built Korean War Veterans Memorial on the National Mall and the upcoming fiftieth anniversary commemorative events should now provide well-deserved recognition. I hope that this series of brochures on the campaigns of the Korean War will have a similar effect.

The Korean War still has much to teach us: about military preparedness, about global strategy, about combined operations in a military alliance facing blatant aggression, and about the courage and perseverance of the individual soldier. The modern world still lives with the consequences of a divided Korea and with a militarily strong, economically weak, and unpredictable North Korea. The Korean War was waged on land, on sea, and in the air over and near the Korean peninsula. It lasted three years, the first of which was a seesaw struggle for control of the peninsula, followed by two years of positional warfare as a backdrop to extended cease-fire negotiations. The following essay is one of five accessible and readable studies designed to enhance understanding of the U.S. Army's role and achievements in the Korean conflict.

During the next several years the Army will be involved in many fiftieth anniversary activities, from public ceremonies and staff rides to professional development discussions and formal classroom training. The commemoration will be supported by the publication of various materials to help educate Americans about the war. These works will provide great opportunities to learn about this important period in the Army's heritage of service to the nation.

This brochure was prepared in the U.S. Army Center of Military History by William J. Webb. I hope this absorbing account, with its list of further readings, will stimulate further study and reflection. A complete listing of the Center of Military History's available works on the Korean War is included in the Center's online catalog:

Brigadier General, USA
Chief of Military History


The Outbreak
27 June-15 September 1950

Korea, a small country numbering 30 million people in 1950, lies at the point where three great Asian powers meet- Japan, China, and the former Soviet Union. Japan ruled Korea from 1910 to 1945. Following the defeat of Japan in World War II, the United States and the Soviet Union jointly occupied the country, the United States south of the 38th Parallel and the Soviet Union north. Preoccupied with Soviet intentions in western Europe, the United States attached little strategic importance to Korea in the late 1940s. America did assist the South Koreans in national elections and in formation of the Republic of Korea (ROK). The Soviet Union, on the other hand, took an active role in governing North Korea and in formation of the Democratic People’s Republic of Korea (DPRK). The United States Army withdrew its combat forces from South Korea in 1949 but left a military advisory group to assist the ROK Army. In early 1950 the Soviets supplied weapons to and assigned several thousand Russian soldiers as trainers for the North Korean People’s Army (NKPA). Armed clashes between North and South Korea were common along the 38th Parallel, but in June 1950 American observers did not anticipate an invasion of the South. Determined to unite Korea by force, the North Koreans invaded South Korea on 25 June. An initially hesitant United States decided that it must take a stand against this armed aggression. American military intervention was ineffective at first, but by September 1950 the combined efforts of the U.S. and ROK Armies, complemented by air and naval superiority, held the North Koreans in check at the Pusan Perimeter.

Strategic Setting

Korea is a mountainous peninsula jutting from the central Asian mainland with a shape that resembles the state of Florida. Water outlines most of this small country, which has more than 5,400 miles of coastline. The Yalu and Tumen Rivers define much of its northern boundary, while major bodies of water are located on its other sides: the Sea of Japan on the east, the Korea Strait on the south, and the Yellow Sea on the west. China lies above the Yalu and Tumen Rivers for 500 miles of Korea’s northern boundary as does the former Soviet Union for some eleven miles along the lower Tumen River. Korea varies between 90 and 200 miles in width and 525 to 600 miles in


Map: Korea


length. High mountains drop down abruptly to deep water on the east where there are few harbors, but a heavily indented shoreline on the south and west provides many harbors. Summers are hot and humid, with a monsoon season that lasts from June to September, but in the winter cold winds roar down from the Asian interior. A rugged landscape, a lack of adequate roads and rail lines, and climatic extremes make large-scale modern military operations in Korea difficult. In 1950 the country’s population totaled about 30 million: 21 million south of the 38th Parallel, with 70 percent of the people engaged in agriculture, and 9 million north.

Japan annexed Korea in 1910 and ruled the country until the end of World War II. Unlike the Soviet Union, in 1945 the United States attached little strategic importance to Korea. At the Potsdam Conference Soviet authorities told American representatives that the Soviets would attack Korea after declaring war on Japan, but the collapse of Japan in August 1945 made a major assault unnecessary. As a line to divide Korea into Soviet and American areas for accepting Japanese surrender, the U.S. War Department selected the 38th Parallel, roughly splitting the country in half. The Soviets agreed to operate in the north, and the American forces would operate in the south. Also in August 1945 the Joint Chiefs of Staff designated General of the Army Douglas MacArthur, as Supreme Commander for the Allied Powers, to receive the Japanese surrender. MacArthur selected Lt. Gen. John R. Hodge, XXIV Corps commander, to command the United States Army Forces in Korea (USAFIK), which administered South Korea on behalf of the United States. The foreign ministers of the United States, Great Britain, and the Soviet Union met in Moscow in December 1945 and developed a plan for a four-power trusteeship of Korea for up to five years. Many South Koreans wanted their independence immediately and protested violently. The Soviets had their own special plans, which involved strong support for the Korean Communist Party that assumed political power in the North under Kim Il Sung.

In August 1947 the United States, Great Britain, and China agreed to reconsider establishment of a four-power trusteeship to facilitate Korean unification, but the Soviet Union refused to cooperate. The United States then proposed that the United Nations (UN) supervise elections in both zones of Korea and that it oversee the formation of a national government. Elections took place in South Korea in May 1948, but the North Koreans neither participated in nor recognized the results of the elections. The South Koreans chose representatives for the National Assembly of the new Republic of Korea, which then


elected Syngman Rhee as its chairman. In July 1948 the assembly produced a constitution and elected Rhee as president of the republic. USAFIK’s governmental authority then came to an end. In September 1948 the North Koreans formed their own government, the Democratic People’s Republic of Korea under the leadership of Kim Il Sung, that claimed jurisdiction over all of Korea. The National Security Council recommended that all U.S. combat troops leave Korea by the end of June 1949, and President Harry S. Truman approved the recommendation.

Attempts to build a native defense force in South Korea began shortly after the end of World War II. In January 1946 the Joint Chiefs of Staff authorized General MacArthur to form a Korean police force and, despite problems with equipment and training, the Korean Constabulary grew to 20,000 men by the close of 1947. Washington asked MacArthur about the advisability of creating a South Korean army. MacArthur proposed instead in February 1948 an increase of the Constabulary to 50,000 men. President Rhee asked in November for an American military mission, and the Provisional Military Advisory Group established by MacArthur in August 1948 was redesignated in July 1949 the United States Military Advisory Group to the Republic of Korea (KMAG) and authorized 472 soldiers. In November 1948 South Korea passed the Armed Forces Organization Act, which created a department of national defense. By March 1949 the South had converted its Constabulary brigades into an Army of 65,000 men assigned to eight tactical divisions—the 1st, 2d, 3d, 5th, 6th, 7th, 8th, and Capital Divisions. In June 1950 the ROK armed forces consisted of the following: Army, 94,808; Coast Guard, 6,145; Air Force, 1,865; and National Police, 48,273.

In the early summer of 1950 four ROK divisions held positions along the 38th Parallel: the 1st, 6th, 7th, and 8th. The 17th Regiment of the Capital Division was on the western extreme in the Ongjin Peninsula. The other four divisions were scattered about the interior and southern parts of the country. The headquarters of the Capital Division was located at Seoul, the 2d near Taejon, the 3d at Taegu, and the 5th at Kwangju in southwest Korea. When U.S. Armed Forces in Korea withdrew from South Korea in 1949, it transferred equipment to the ROK Army sufficient for 50,000 men. The weapons of the ROK divisions stationed along the 38th Parallel included the American M1 rifle, .30-caliber carbine, 60-mm. and 81-mm. mortars, 2.36-inch rocket launchers, and the M3 105-mm. howitzer. The South Korean armed forces had no tanks, no medium artillery, and no fighter aircraft or bombers. In October 1949 the ROK minister of defense had requested


M26 Pershing tanks from the United States, but the KMAG staff concluded that the rough Korean terrain and inadequate roads would not allow efficient tank operations. In June 1950 the ROK Army possessed some 2,100 serviceable U.S. Army motor vehicles—830 21/2-ton trucks and 1,300 1/4-ton trucks (jeeps). The ROK Air Force consisted of twelve liaison-type aircraft and ten advance trainers (AT6). The ROK Navy had a sprinkling of small vessels that included patrol craft along with mine layers and sweepers.

The North Korean People’s Army was officially activated in February 1948. The Soviets exercised close control over its organization and training, and Soviet advisers worked directly with units. At that time 150 Soviets were assigned to each division; the number dropped to 20 per division in 1949 and to a lesser number by 1950 as trusted North Korean officers were developed. By June 1950 the NKPA and the Border Constabulary numbered about 135,000. The primary tactical units consisted of eight full-strength infantry divisions of 11,000 men each, two more infantry divisions at half strength, a separate infantry regiment, a motorcycle-reconnaissance regiment, and an armored brigade. The NKPA benefited from some 20,000 North Koreans who were veterans of the Chinese civil war of the late 1940s, which gave its units a combat-hardened quality and efficiency. The Soviet Union supplied much of the materiel for the NKPA. Of primary importance was the T34 medium tank, a mainstay of the Soviet armored force in World War II that weighed 32 tons and mounted an 85-mm. gun. The Soviets also supplied artillery support that resembled the weaponry of the older Soviet division of World War II: 76-mm. and 122-mm. howitzers, 45-mm. antitank guns, and 82-mm. and 120-mm. mortars. At the outset of the war North Korea had about 180 Soviet aircraft- 60 YAK trainers, 40 YAK fighters, 70 attack bombers, and 10 reconnaissance planes. Like the ROK Navy, the North Korean naval forces had only a few small vessels- sixteen patrol craft and several coastal steamers.

U.S. strategic planning after World War II centered on the Soviet Union and its satellite nations. In 1950, as the single most powerful nation in the North Atlantic Treaty Organization, America gave first claim for its military resources to the defense of western Europe. Not only did the United States give priority to Europe over the Pacific and Far East, in April 1948 President Truman had approved a policy that no problems within Korea could become a casus belli for the United States. In January 1950, in a speech to the National Press Club in Washington, D.C., Secretary of State Dean G. Acheson announced an American defensive strategy in the Far East that excluded both Korea and Formosa.


The Joint Chiefs of Staff had designated General MacArthur as Commander in Chief, Far East Command (FEC), effective January 1947. The boundaries of FEC were not specific, but MacArthur commanded forces in Japan, Korea, the Philippines, and other island groups. He was responsible for the American occupation of and for general emergencies in those areas. Along with United States Army Forces, Far East, MacArthur also controlled Far East Air Forces and Naval Forces, Far East.

In June 1950 the active United States Army had an authorized strength of 630,201 with an actual strength of about 591,000 and ten combat divisions. Some 360,000 troops were at home, while the remaining 231,000 were in overseas commands with 80,000 in Germany and 108,500 in the Far East. The force designated to handle the Army’s emergency assignments was the General Reserve, which consisted mainly of five combat divisions stationed in the United States: 2d Armored Division, 2d and 3d Infantry Divisions, and the 11th and 82d Airborne Divisions. The Far East Command had four tactical divisions and a regimental combat team (RCT)- the 1st Cavalry Division, the 7th, 24th, and 25th Infantry Divisions, and the 29th RCT- that operated under the command of the Eighth U.S. Army in Japan. Each division was short of its authorized war strength of 18,900 by nearly 7,000 men and had major shortages in artillery batteries and equipment. The FEC had received no new vehicles, tanks, or other equipment since World War II. Army personnel stationed in Japan had performed primarily occupation duties, and no serious effort had been made to attain combat efficiency at battalion level or higher. Convinced that a purely occupational mission was no longer needed, MacArthur issued a policy directive in April 1949 that called for an intensified training program for ground, naval, and air units in FEC. By May 1950 Eighth Army’s divisions had reportedly reached combat readiness levels that ranged from 65 to 84 percent.

As early as 1947 the North Korean Communists employed propaganda and even armed violence to instigate the overthrow of the South Korean government. On 3 May 1949, the North Koreans launched their first open attack across the 38th Parallel in the vicinity of Kaesong, but ROK units repulsed them. Hundreds of small-scale assaults occurred across the parallel during the first half of 1950; however, some encounters inflicted heavy casualties on both sides. A series of guerrilla uprisings on the island of Cheju-do spread to the mainland by late 1948, but by June 1950 the ROK Army had virtually eliminated them, claiming to have killed about 5,000 insurgents. By late 1949 talk of a North Korean invasion was almost routine in intelli-


gence circles, but it went unnoticed against the background of threatening Communist activities in other parts of the world- Southeast Asia, western Europe, and the Middle East. In the early summer of 1950 senior American observers discounted the likelihood of a North Korean invasion. Both Maj. Gen. Charles A. Willoughby, the FEC G-2 (intelligence officer), and the American embassy in Seoul opined that an attack was unlikely and that the North Koreans would continue to employ guerrillas and psychological warfare. The officers of the KMAG felt that an attack by North Korea was not imminent and, if it happened, they thought that the South Koreans could repel it. Since the United States had no plan to counter an invasion, any debate about an American intelligence failure regarding the North Korean attack was academic.


During 15-24 June 1950, the North Korean High Command assembled some 90,000 men- 7 infantry divisions, 1 armored brigade, 1 separate infantry regiment, 1 motorcycle regiment, and 1 Border Constabulary brigade- supported by 150 Soviet T34 tanks near the 38th Parallel. At 0400 on 25 June the North Koreans launched a coordinated attack on South Korea that ran from coast to coast. The assault began on the Ongjin Peninsula on the western extreme of the parallel, but the North Koreans concentrated half of their forces on the Uijongbu Corridor, an ancient invasion route that led directly south to Seoul. The ROK 1st, 2d, 7th, and Capital Divisions defended the area north of Seoul, but the suddenness of the North Korean attack and the shock of enemy armor rapidly pushed the ROK Army back toward Seoul. In the early hours of 28 June the South Korean vice minister of defense ordered a premature blowing of the Han River bridges, located on the southern edges of Seoul, to slow the North Korean advance. This was catastrophic for the ROK Army. Much of the Army was still north of the river and had to abandon transport, supplies, and heavy weapons and cross the Han River in disorganized groups. The ROK Army numbering 95,000 on 25 June could account for only 22,000 men at the end of June.

The UN Security Council met on 25 June and passed a resolution that called on North Korea to cease hostilities and withdraw to the 38th Parallel. President Truman authorized ships and airplanes to protect the evacuation of American dependents in Korea and also use of American air and naval forces to support the Republic of Korea below the 38th Parallel. On 27 June the UN Security Council passed another


Map: The North Korean Invasion

resolution that recommended UN members assist South Korea in repelling the invasion. The Joint Chiefs of Staff issued a directive that authorized MacArthur to assume operational control of all American military activities in Korea. MacArthur then sent the General Headquarters Advance Command and Liaison Group in Korea


General MacArthur discusses the military situation with Ambassador John J. Muccio at ROK Army headquarters, 29 June 1950.
General MacArthur discusses the military situation with Ambassador John J. Muccio at ROK Army headquarters, 29 June 1950.
(National Archives)

(ADCOM), headed by Brig. Gen. John H. Church, from Japan to South Korea to administer KMAG and assist the ROK Army. On 29 June MacArthur personally inspected the situation at the Han River and urged the immediate commitment of American ground forces. President Truman then authorized the employment of Army combat troops to ensure a port and air base at Pusan, South Korea, and more importantly, approved sending two Army divisions from Japan to Korea and the establishment of a naval blockade of North Korea.

Following the breakdown of the ROK Army at Seoul, elements of the North Korean 3d and 4th Divisions captured the South Korean capital on 28 June. The North Koreans then repaired a railroad bridge over the Han River, and by 4 July these two divisions, with T34 tank support, were poised to resume their drive south. In Tokyo on 30 June General MacArthur instructed Lt. Gen. Walton H. Walker, Eighth U.S. Army commander, to order the 24th Infantry Division, stationed on Kyushu, to Korea at once. Maj. Gen. William F. Dean, commander of the 24th, was to send immediately to Korea by air a delaying force of about 500 men, and the rest of the division would soon follow by


water. General Dean would assume command of USAFIK, reinstated as a provisional headquarters, upon his arrival. Lt. Col. Charles B. Smith, commander of the 1st Battalion, 21st Infantry, of the 24th Division, led the delaying force, called Task Force Smith. On 5 July he established a defensive position three miles north of Osan, assisted by elements of the 52d Field Artillery Battalion. Task Force Smith took on two regiments of the North Korean 4th Division and thirty-three T34 tanks. Badly outnumbered and without armor, effective antitank weapons, or air support, the U.S. force was overrun. The next day, Colonel Smith could assemble only 250 men, half his original force.

On 4 July General Dean assumed command of USAFIK and established his headquarters at Taejon. The 34th Infantry, another organic regiment of Dean’s 24th Division, and the rest of the 21st Infantry arrived in Korea during the first week of July. During that week General MacArthur ordered General Walker to deploy from Japan and assume operational control of the campaign in Korea. Walker set up his headquarters for the Eighth U.S. Army in Korea at Taegu and on 13 July assumed command of USAFIK. Shortly thereafter, he also took command of ROK ground forces. Walker’s objectives were to delay the enemy advance, secure the current defensive line, and build up units and materiel for future offensive operations. On 7 July the UN Security Council passed a resolution that recommended a unified command in Korea. President Truman then appointed MacArthur commanding general of the military forces under the unified command that became the United Nations Command. MacArthur’s strategy in the early stages of the Korean War was first to stop the North Koreans and then use naval and air superiority to support an amphibious operation in their rear. Once he realized that the North Korean People’s Army was a formidable force, MacArthur estimated to the Joint Chiefs of Staff that to halt and hurl back the North Koreans would require four to four-and-a-half full-strength infantry divisions, an airborne regimental combat team, and an armored group of three medium tank battalions and reinforcing artillery.

After the defeat of Task Force Smith, General Dean employed the 34th and 21st Infantries in additional delaying actions against the advance of the North Korean 3d and 4th Divisions along the corridor that ran south of Osan toward Taejon. Fighting occurred at P’yongt’aek, Ch’onan, Chonui, and Choch’iwon. Dean sought to delay the enemy’s approach to the Kum River to support the ROK forces’ left flank that was retreating through the central mountains of South Korea. By early July the ROK Army, which became badly disorganized after the fall of Seoul, had re-formed to some extent. From west


to east, the ROK Army line was held by the 17th Regiment; the 2d, Capital, 6th, and 8th Divisions; and the 23d Regiment of the 3d Division. The major part of the NKPA conducted a main attack on a wide front against ROK-defended territory, which was everything east of the main Seoul-Taegu railroad and highway. Five divisions moved south over the two mountain corridors, while a sixth, the 2d Division, followed the road from Ch’ongju through Poun to Hwanggan where it entered the Seoul-Taegu highway. The North Korean 1st, 13th, and 15th Divisions moved over one mountain corridor and across the Mun’gyong plateau, while the 8th and 12th Divisions came down the eastern corridor. On the east coast along the Sea of Japan, the North Korean 5th Division and the 766th Independent Infantry Regiment marched south and met virtually no opposition. The trackless mountains of the Taebaek Range effectively separated the east coast of Korea below the 38th Parallel from the rest of the country.

In mid-July 1950 General Dean’s 24th Division continued as the primary U.S. Army fighting force in Korea. Taejon, located 100 miles south of Seoul, served as an important road and communications center. The Kum River makes a semicircle to the north around Taejon that constitutes a protective moat. Dean placed his 24th Division in a horseshoe-shaped arc in front of Taejon—the 34th Infantry on the left, the 19th Infantry on the right, and the 21st Infantry in reserve. By positioning elements of the 34th at Kongju, located about twenty miles northwest of Taejon, Dean hoped to prevent the North Koreans from an early crossing of the Kum River and an immediate drive on Taejon. Since the division had only about 4,000 men at Taejon, the 24th could not effectively delay two enemy divisions. During 14–16 July the North Korean 4th and 3d Divisions, operating west to east, penetrated the 34th and 19th Infantries’ forward defensive positions on the south side of the Kum River and inflicted substantial casualties. Dean then pulled his regiments into a tighter defensive perimeter around Taejon, and the North Koreans launched their attack on Taejon on 19 July. The men of the 24th at Taejon enjoyed one positive development. They had just received a weapon that was effective against the T34 tank, the new 3.5-inch rocket launcher. The five-foot hand-carried launcher fired a two-foot-long eight-and-a-half-pound rocket with a shaped charge designed to burn through any tank then known. U.S. Army soldiers destroyed ten enemy tanks in Taejon on 20 July, eight of them with the 3.5-inch rocket launcher.

The superior numbers and relentless assault of the North Koreans forced the men of the 24th Division to abandon Taejon on 20 July and withdraw to the south. General Dean experienced one of the most dra-


General Walker (left) is greeted on arrival at Taejon by General Dean.
General Walker (left) is greeted on arrival at Taejon by General Dean.
(National Archives)

matic adventures of the withdrawal. Moving down the road to Kumsan, Dean and a small party encountered an enemy roadblock. Forced back, Dean’s party, with some wounded, set out on foot after dark. While trying to fetch water for the injured, Dean fell down a steep slope, was knocked unconscious, and suffered a gashed head and a broken shoulder. Separated from his men, Dean wandered alone in the mountains for thirty-six days trying to reach the American lines and was betrayed by two South Koreans to the North Koreans. He would spend the next three years as a prisoner of war. Dean was awarded the first Medal of Honor for service in the Korean War for his leadership and personal bravery with the 24th Division at Taejon. The division suffered a 30 percent casualty rate there and lost all of its organic equipment. The unit had endured many deficiencies since its arrival in Korea. Among them were new subordinate unit commanders who were unfamiliar with their men, poor communications equipment, a shortage of ammunition, outdated maps, and large numbers of young soldiers in the ranks who were inadequately trained for combat. As for the North Koreans, in five days they had executed two highly successful envelopments of American positions, one at the Kum River and the


A 3.5-inch rocket launcher on a battlefield, 20 July 1950
A 3.5-inch rocket launcher on a battlefield, 20 July 1950
(National Archives)

other at Taejon. Each time, they combined strong frontal attacks with movements around the left flank to establish roadblocks and obstruct the escape routes.

The 24th Division would soon share the defense of South Korea with the rebuilt ROK Army and two newly arrived U.S. Army divisions, the 25th Infantry Division and the 1st Cavalry Division. On 24 July the ROK Army reorganized itself into two corps and five divisions. The ROK I Corps controlled the 8th and Capital Divisions, while the ROK II Corps controlled the 1st and 6th Divisions. A reconstituted ROK 3d Division was placed under direct ROK Army control. The ROK II Corps headquarters was at Hamch’ang with its 1st and 6th Divisions on line from west to east, and the I Corps headquarters was at Sangju with the 8th and Capital Divisions on line from west to east. The 3d Division operated on the east coast of South Korea. Large numbers of recruits and replacements had entered the ROK Army, which had regained its prewar strength of about 95,000. The U.S. 25th Division, with its three regiments—24th, 27th, and 35th—commanded by Maj. Gen. William B. Kean, arrived during 10–15 July 1950 at Pusan. General Walker ordered the 25th to bolster ROK defenses of the central mountain corridors. The 1st Cavalry Division, with its three regiments—5th, 7th, and 8th—sailed from


Japan and landed at P’ohang-dong north of Pusan during 15–22 July. The unit assumed responsibility for blocking the enemy along the main Taejon-Taegu corridor. In late July both the 25th Division and the 1st Cavalry Division withdrew steadily in the face of aggressive North Korean attacks. On 29 July General Walker, with the support of General MacArthur, issued what the press called a "stand or die" order to the Eighth Army. Walker emphasized that the retreating must stop. The Eighth Army had been trading space for time and was running out of space.

One of the major problems of the retreat was the volume of refugees moving through Eighth Army lines. Their numbers were greater during July and August 1950 than at any other time in the war. During the middle two weeks of July about 380,000 refugees crossed into ROK-held territory. The North Koreans often exploited the situation by launching attacks that began with herding groups of refugees across minefields and then following up with tanks and infantry. The enemy also infiltrated U.S. Army lines by wearing the traditional white civilian clothing and joining groups of refugees, thus enabling him to commit a variety of surprise attacks on American soldiers. The commanders of the 25th Infantry and 1st Cavalry Divisions attempted unsuccessfully to control the volume of refugees and enemy infiltration by searching displaced civilians and limiting the times and routes available for their movements. In late July General Walker, with the cooperation of ROK authorities, set explicit rules for the organized removal of refugees to the rear by the ROK National Police. By the end of July the ROK government had established fifty-eight refugee camps, most of them in the Taegu-Pusan area, to care for the homeless. But even with these efforts, refugees continued to hamper the movement of U.S. and ROK troops throughout the battlefield.

As the Eighth Army neared a natural defensive position along the Naktong River, the North Koreans accelerated their efforts to cut off elements of that army. After the fall of Seoul in late June the North Korean 6th Division had crossed the Han River and rapidly moved south over the western coastal roadnet. Eighth Army intelligence lost track of the 6th. The only UN forces situated at the time southwest of the Taejon-Taegu-Pusan highway were a few hundred ROK 7th Division survivors along with some scattered ROK marines and local police. On 21 July General Walker learned that a North Korean unit, presumed to be the 4th Division, was operating in the southwest area. Walker ordered the 24th Division, despite its deficiencies in manpower and equipment after the loss of Taejon, to serve as a blocking force in the area from Chinju in deep south central Korea northward to


Kumch’on. Two battalions of the 29th Infantry, then stationed on Okinawa, and the ROK 17th Regiment would reinforce the 24th Division. On 23 July the North Korean 4th Division moved south from Taejon with the intent of supporting the 6th Division in an envelopment of the United Nations’ left flank and driving to Pusan. The 4th pushed as far as the Anui-Koch’ang area, about fifty miles southwest of Taegu, by the end of July. During 25–28 July the two battalions of the 29th were driven back by elements of the 6th at Hadong, located about twenty-five miles west of Chinju. On 31 July the Eighth Army finally became aware of the 6th Division’s presence after the 6th took Chinju and forced one battalion of the 29th and the 19th Infantry of the 24th Division to withdraw to the east. Eighth Army rushed the 27th Infantry of the 25th Division, which had been in reserve, to reinforce American units in the Chinju-Masan corridor. The 24th and 25th Divisions, aided by the ROK 17th Regiment, finally managed to slow the progress of the North Korean 4th and 6th Divisions at what would become the southernmost sector of the Pusan Perimeter. By 3 August U.S. and ROK units had averted the immediate threat of a North Korean drive all the way to Pusan.

On 1 August the Eighth Army issued an operational directive to all UN ground forces in Korea for their planned withdrawal east of the Naktong River. UN units would then establish main defensive positions behind what was to be called the Pusan Perimeter. The intent was to draw the line on retreating and hold off the NKPA while the U.S. Army could build up its forces and wage a counteroffensive. The Pusan Perimeter assumed by U.S. and ROK forces on 4 August involved a rectangular area about 100 miles from north to south and 50 miles from east to west. The Naktong River formed the western boundary except for the southernmost 15 miles where the Naktong turned eastward after its confluence with the Nam River. The ocean formed the eastern and southern boundaries, while the northern boundary was an irregular line that ran through the mountains from above Waegwan to Yongdok. From the southwest to the northeast the UN line was held by the U.S. 25th and 24th Infantry and 1st Cavalry Divisions, and then by the ROK 1st, 6th, 8th, Capital, and 3d Divisions. From south to northeast the North Korean units positioned opposite the UN units were the 83d Motorized Regiment of the 105th Armored Division and then the 6th, 4th, 3d, 2d, 15th, 1st, 13th, 8th, 12th, and 5th Divisions and the 766th Independent Infantry Regiment. The 5th Regimental Combat Team from Hawaii and the phased arrival of the 2d Infantry Division from the United States augmented U.S. Army forces. A third major reinforcement arrived in Korea on 2


Map: The Pusan Perimeter


August, the 1st Provisional Marine Brigade, about 4,700 men. UN combat forces at this point actually outnumbered the North Koreans, 92,000 to 70,000.

The North Koreans had four possible avenues of advance leading to Pusan that could result in the defeat of U.S. and ROK forces, and in August they tried them all simultaneously. These approaches went through Masan south of the confluence of the Nam and Naktong Rivers, through the Naktong Bulge to the rail and road lines at Miryang, through Kyongju and down the east coast corridor, and through Taegu. During the first week of August General Walker decided to launch the first American counterattack of the war in the Chinju-Masan corridor. One of his purposes was to break up a suspected massing of enemy troops near the Taegu area by forcing the diversion of some North Korean units southward. On 6 August the Eighth Army issued the operational directive for the attack by Task Force Kean, named for the 25th Division commander. Task Force Kean consisted of the 25th Division, less the 27th Infantry and a field artillery battalion, with the 5th RCT and the 1st Provisional Marine Brigade attached. The Army plan of attack required the force to move west from positions then held near Masan, seize the Chinju Pass, and secure the line as far as the Nam River. Task Force Kean launched its strike on 7 August but ran head-on into one being delivered simultaneously by the North Korean 6th Division. After a week of heavy fighting, neither Kean’s troops nor their opponents had made any appreciable progress. Even so, the Eighth Army had launched its first offensive in Korea and successfully halted an assault by an enemy division.

Seven air miles north of the point where the Naktong River turns east and the Nam River enters it, the Naktong curves westward opposite Yongsan in a wide semicircular loop. This loop became known to the American troops as the Naktong Bulge during the bitter fighting there in August and September. On 6 August the North Korean 4th Division crossed the Naktong at Ohang with the intent of driving to Yongsan located about ten miles to the east. The 24th Division defended that sector and the 24th commander, Maj. Gen. John H. Church, who had succeeded General Dean as division commander, placed the defense of the Naktong Bulge under Task Force Hill. Task Force Hill consisted of the 9th Infantry of the 2d Infantry Division along with the 34th and 19th Infantries and a battalion of the 21st Infantry of the 24th Division. Despite the efforts of Task Force Hill, by 11 August the 4th Division had penetrated to the vicinity of Yongsan. General Walker then added to the fray the 23d Infantry of the 2d Division, the 27th Infantry of the 25th Division, and the 1st Provisional Marine Brigade.


Two American soldiers with a North Korean prisoner of war, 5 August 1950
Two American soldiers with a North Korean prisoner of war, 5 August 1950 (National Archives)

General Church led the coordinated attack of Army and Marine Corps troops against the North Koreans that began on 17 August. By the eighteenth the American forces had decisively defeated the 4th Division, which had lost half its original strength of about 7,000 men.

Located about twenty miles south of P’ohang-dong on the east coast, Kyongju was an important rail and highway center situated


within the Taegu–P’ohang-dong–Pusan triangle inside the Pusan Perimeter. The capture of P’ohang-dong and the nearby Yonil Airfield, used by the Far East Air Force, would open a natural and essentially undefended corridor for the NKPA to move directly south through Kyongju to Pusan. General Walker had only lightly fortified the east coast corridor because the enemy threat was more immediate on the western perimeter, and he doubted that the North Koreans could mount a major successful drive through the trackless mountains. In early August the enemy almost proved Walker wrong when three North Korean divisions—the 5th, 8th, and 12th—and the 766th Independent Infantry Regiment mounted strong attacks against the ROK defenders. By 12 August the North Koreans had pressed to P’ohang-dong and also threatened Yonil Airfield. The North Korean 5th Division cut off the ROK 3d Division above P’ohang-dong, and the 3d Division had to be evacuated by sea to positions farther south. General Walker reinforced the ROK units in the area with elements of the U.S. 2d Infantry Division. By 17 August ROK units and the 2d Division had managed to check the enemy drive at P’ohang-dong. A primary factor in stopping the North Koreans was logistics, as the enemy had outrun his supply line during the difficult trek southward through the mountains.

The natural corridor of the Naktong Valley from Sangju to Taegu presented another principal axis of attack for the NKPA. The sizable enemy forces assembled in an arc around Taegu in early August from south to north consisted of the 10th, 3d, 15th, 13th, and 1st Divisions and elements of the 105th Armored Division. Opposite the North Korean divisions were the U.S. 1st Cavalry Division and the 1st and 6th Divisions of the ROK II Corps. The North Koreans crossed the Naktong River in several places within the arc around Taegu during the second week of August. When several enemy artillery shells landed in Taegu on 18 August, President Rhee ordered movement of the Korean provincial government, then in Taegu, to Pusan. The North Korean 1st and 13th Divisions posed the primary threat as they pressed toward Taegu by overland routes from the north and northwest. General Walker moved up the 23d and 27th Infantries, both fresh from defensive action in the Naktong Bulge, to reinforce the ROK 1st Division, which confronted the North Korean 1st and 3d Divisions in its sector. Although the North Korean 1st Division pushed to within nine miles of Taegu, the combined efforts of the ROK 1st Division and the U.S. 23d and 27th Infantries frustrated enemy efforts to penetrate to Taegu.

Even though the North Korean People’s Army had seriously threatened the United States and ROK Armies within the Pusan Perimeter


during August 1950, the defenders both successfully resisted the enemy attacks and continued the buildup of forces for a counteroffensive. The Far East Air Force had established air supremacy over the North Koreans early in the war and continued to influence the outcome of battles by multiple sorties in close support of ground troops, 4,635 in July and 7,397 in August. By late August there were more than 500 American medium tanks within the Pusan Perimeter. The tanks in tank battalions were equally divided between M26 Pershings and M4A3 Shermans, except for one battalion that had the newer M46 Pattons. On 1 September the United Nations Command had a strength of 180,000 in Korea: 92,000 were South Koreans and the balance were Americans and the 1,600-man British 27th Infantry Brigade. In August the North Koreans continued the plan and tactics begun at the Han River in early July with a frontal holding attack, envelopment of the flank, and infiltration to the rear. When the Eighth Army stabilized the line at the Pusan Perimeter, these tactics no longer worked and success could come only by frontal attack, penetration, and immediate exploitation. Generals MacArthur and Walker countered with classical principles of defense—interior lines of communications, superior artillery firepower, and a strong air force. By 1 September the North Koreans had assembled a 98,000-man army for a massive offensive against the Pusan Perimeter. However, they experienced substantial problems: a third of their ranks manned by forcibly conscripted and untrained South Koreans, a major shortage of small arms, and only enough rations for one or sometimes two meals a day.

In early September as during August, General Walker faced dangerous situations in essentially the same places along the Pusan Perimeter: in the east at P’ohang-dong to include a potential severing of the corridor between Taegu and P’ohang-dong, north of Taegu where the enemy made disturbing gains, at the Naktong Bulge, and in the Masan area in the extreme south. Also as he had during the fighting in August, Walker continued his masterful tactics of shifting his forces from one threatened enemy penetration to another. In early September the ROK 3d, Capital, 8th, and 6th Divisions held the line farthest to the east against the North Korean 5th, 8th, 12th, and 15th Divisions. Maj. Gen. John B. Coulter, newly appointed deputy commander, Eighth Army, assumed command of American units in the eastern sector and employed the 21st Infantry of the U.S. 24th Division and other supporting units to bolster the ROK divisions. On 7 September General Church replaced Coulter as American commander in the eastern sector after General Walker ordered the entire 24th to reinforce the ROK divisions. A combination of ground fighting, pre-


Map: Defense of the Naktong


dominantly by the South Koreans, along with American close air support and naval gunfire from offshore inflicted serious losses on the enemy divisions. The North Korean 1st, 3d, and 13th Divisions pressed the attack north of Taegu against the U.S. 1st Cavalry Division, which prompted Walker on 5 September to move the main Eighth Army headquarters from Taegu to Pusan. The 1st Cavalry Division essentially checked the thrusts of the North Koreans north of Taegu, but fighting continued there into mid-September.

At the end of August the North Korean People’s Army also planned a crushing blow against the U.S. 2d and 25th Divisions in the southern part of the Pusan Perimeter. The enemy’s 6th Division would attack through Haman, Masan, and capture Kumhae, fifteen miles west of Pusan. The 7th Division was to strike north of the Masan highway, wheel left to the Naktong River, and wait for the 6th Division on its right and the 9th on its left and then resume the attack toward Pusan. The 25th Division held the southernmost sector that ran from the confluence of the Naktong and Nam Rivers to the southern coast, while the 2d Division was positioned in the area across the Naktong River north of the 25th. The North Korean 9th Division faced the 2d Division at the Naktong Bulge and had the mission of capturing the towns of Miryang and Samnangjin, thereby cutting off the Eighth Army route of withdrawal between Taegu and Pusan. During the first week of September the 9th Division penetrated the Naktong Bulge as far east as Yongsan, but a counterattack by the 2d Division together with the U.S. 1st Provisional Marine Brigade pushed back the 9th almost to the Naktong River. The 2d Division’s 23d Infantry beat back the North Korean 2d Division six miles north of Yongsan at Changnyong. At the same time the 6th and 7th Divisions mounted strong attacks against the 25th Division. Despite enemy penetrations into the sectors of the 25th’s regiments—the 35th Infantry’s sector west of Ch’irwon and the 24th Infantry’s sector near Haman that was effectively stopped by the 27th Infantry—the 25th Division repelled the NKPA’s offensive in the south. The Naktong River line held, and the Pusan Perimeter was secure.


Within the space of a few months in 1950, the United States had taken the big leap from attaching no strategic importance to Korea to active involvement there in a major armed conflict. Its active Army of 591,000 had been focused on Soviet intentions in western Europe and occupation duty in Europe and the Far East. The four divisions under


Medics evacuate wounded of the 5th Regimental Combat Team hit near Masan, 30 August, 1950.
Medics evacuate wounded of the 5th Regimental Combat Team hit near Masan, 30 August 1950.
(National Archives)

MacArthur’s Far East Command in Japan were performing primarily occupation duties, and their actual readiness level for conventional combat was even lower than their marginal statistical ratings indicated. Each of MacArthur’s divisions was about 7,000 men short of its authorized strength of 18,900, and none of them had received any new equipment since World War II. MacArthur had not fully supported development of the ROK Army, and in 1948 he had suggested merely expanding the ROK Constabulary. When the ROK minister of defense in 1949 requested M26 Pershing tanks from America, the KMAG argued that the Korean terrain and roads would not allow tank operations, a clearly inaccurate prediction of the Soviet T34 tank’s performance in South Korea during the war’s early stages. When USAFIK withdrew from South Korea in 1949, it did transfer to the ROK Army individual weapons and equipment sufficient for 50,000 men, but these small arms were incapable of repelling enemy armored attacks.

America failed to anticipate the North Korean invasion, and KMAG erred in concluding that the ROK Army could withstand an invasion if it happened. Nevertheless, when the attack came the United States decided to intervene on behalf of South Korea. President Truman authorized air and naval support early in the conflict and the progressive introduction of ground troops. The defeat of Task Force Smith underscored the importance of adequate prewar training along with armored and air support in combat operations. Further, MacArthur underestimated the skill and determination of the North Koreans but recognized his error when he concluded that more than four U.S. divisions were needed to defeat the enemy. The combined efforts of the U.S. and ROK Armies led by General Walker, complemented by air and naval superiority, slowed the southward drive of the North Koreans and ended in a difficult but successful defense of the


Pusan Perimeter. The fighting was intense as reflected in American casualties to mid-September 1950—4,599 battle deaths, 12,058 wounded, 401 reported captured, and 2,107 reported missing in action. The bitter weeks of retreat and death would soon change, however, with MacArthur’s "hammer against the anvil": the breakout from the Pusan Perimeter coupled with the landing at Inch’on by the 1st Marine Division and the Army’s 7th Infantry Division during the third week of September.








Further Readings

Appleman, Roy E. South to the Naktong, North to the Yalu. United States Army in the Korean War. Washington, D.C.: U.S. Army Center of Military History, 1961.

Blair, Clay. The Forgotten War: America in Korea. New York: Time Books, 1988.

Collins, J. Lawton. War in Peacetime: The History and Lessons of Korea. Boston: Houghton Mifflin, 1969.

Dean, Major General William F. General Dean’s Story. New York: Viking Press, 1954.

Edwards, Paul M. The Pusan Perimeter, Korea, 1950: An Annotated Bibliography. Westport, Conn.: Greenwood Press, 1994.

Ridgway, Matthew B. The Korean War. Garden City, N.Y.: Doubleday, 1967.

Schnabel, James F. Policy and Direction: The First Year. United States Army in the Korean War. Washington, D.C.: U.S. Army Center of Military History, 1972.




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