THE KOREAN WAR

THE OUTBREAK

27 June–15 September 1950
Introduction

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:

www.army.mil/cmh-pg/catalog/brochure.htm.

JOHN S. BROWN

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
Unsan

38° 38°

T a e b a e k M t s

MANCHURIA

Hyesanjin

Ch’osan

Hagaru-ri

Hungnam

Iwon

Wonsan

Sinuiju

Chongju Sinanju

P’YONGYANG

Kaesong

Ch’orwon

Munsan-ni

Uijongbu

Ch’unch’on

Hongch’on

Suwon

Osan

Ch’ungju

Wonju

Chech’on

Samch’ok

Ulchin

Andong

Yangyang

Kansong

Kosong

Kumhwa

P’yonggang

P’ohang-dong

Taegu

PUSAN

Miryang

Masan

Mokp’o

Kunsan

Taejon

SEOUL

Inch'on

an gjin

Ch R

CHANGJIN

(CHOSIN) RES

Ch’ongch’on

R

Taedong

Taeryong

Kur

R

R

yong

R Yalu R

Yesong

R

Imjin

R

Han R Naktong

R

Kum

R

YELLOW

SEA

K O R E A

S T R A I T

SEA

O F

JAPAN

KOREA

High Ground

Above 200 Meters

0 50 MILES
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

5
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

6
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 combathardened 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.

7
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 intelli8
9

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.

Operations

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
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

10

38° 38°

Yangyang

Kangnung

Samch’ok

Ulchin

Yongdok

P’ohang-dong

TAEGU

Uisong

Waegwan

Masan

Sunch’on

Posong

Kwangju

Mokp’o Yosu

Chinju

PUSAN

TSUSHIMA

Kumch’on

Taejon

Kunsan YELLOW

SEA

Chonju

Ch’unch’on

Suwon

Osan

SEOUL

Uijongbu

Inch’on

Ch’ungju

Kaesong

T A E B A E K M O U N T A I N S

Han R

Han R

Kum

R

Naktong R

P'yongt'aek

Ch'onan

Ch'ongju

Choch'iwon

Hamch'ang

Sangju

Koch'ang

Anui

Hadong

SEA

OF 

JAPAN

THE NORTH KOREAN INVASION

25 June–4 August 1950

ELEVATIONS IN METERS

0

2010010 30 40

2010010 40

200 500 1000 AND ABOVE

KILOMETERS

MILES
(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

11

General MacArthur discusses the military situation with 

Ambassador John J. Muccio at ROK Army headquarters, 29 June 1950.

(National Archives)
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

12
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 dra13
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

14

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

(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

15

A 3.5-inch rocket launcher on a battlefield, 20 July 1950

(National Archives)
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

16
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

17
XXXX

WALKER

EIGHTH

5 Aug

Phase Line

26 Aug

Phase Line

XX

25

XX

ROK 3

XX

ROK CAP

XX

ROK 8

XX

ROK 6

XX

ROK 1

XX

1

XX

24

Chinju

Kosong

Masan

PUSAN

Miryang

Kyongju

P'ohang-dong

TAEGU

Yongdok

Kunwi

Kumch'on

Waegwan

Hamch'ang

Sangju

Naktong-ni

Andong

Yech'on

Uisong

Naktong

R

Nam

R

Pyongyong

Naktong

Bulge

THE PUSAN PERIMETER

1 August–1 September 1950

ELEVATIONS IN METERS

0

10 0 10 20

10 0 10 20

200 1000 AND ABOVE

KILOMETERS

MILES
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 ChinjuMasan 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.

19
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

20

Two American soldiers with a North Korean prisoner of war, 

5 August 1950 (National Archives)
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

21
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, pre22
XXXX

WALKER

EIGHTH

10 Sep

Phase Line

XX

ROK 3 XX

ROK CAP

XX

ROK 8

XX

ROK 6

XX

ROK 1

XX

1

XX

25

XX

ROK 7

XX

2

Chinju

Kosong

Masan

PUSAN

Miryang

Kyongju

P'ohang-dong

TAEGU

Yongdok

Kunwi

Kumch'on

Waegwan

Hamch'ang

Sangju

Naktong-ni

Andong

Yech'on

Uisong

Naktong

R

Nam

R

Pyongyong

Naktong

Bulge

DEFENSE OF THE NAKTONG

1–15 September 1950

ELEVATIONS IN METERS

0

10 0 10 20

10 0 10 20

200 1000 AND ABOVE

KILOMETERS

MILES
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.

Analysis

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

24
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

25

Medics evacuate wounded of the 

5th Regimental Combat Team hit

near Masan, 30 August 1950.

(National Archives)
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.

26
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.

27
CMH Pub 19–6

Cover: Troops of the 1st Cavalry Division in action against 

North Korean invaders, 25 July 1950.

PIN : 077983–000