U.S. IX Corps
Encyclopedia
IX Corps was a corps
of the United States Army
. For most of its operational history, IX Corps was headquartered in or around Japan and subordinate to US Army commands in the Far East.
Created following World War I
, the corps was not activated for use until just before World War II
almost 20 years later. The Corps spent most of World War II in charge of defenses on the West Coast of the United States, before moving to Hawaii and Leyte
to plan and organize operations for US forces advancing across the Pacific. Following the end of the war, IX Corps participated in the occupation of mainland Japan.
The Corps' only combat came in the Korean War
. It is best known for its exploits as a senior command of the Eighth United States Army, commanding front line UN forces in numerous offensives and counteroffensives throughout the war. The corps served on the front lines for most of the conflict and took command of several combat divisions at a time. Following the end of the Korean War, IX Corps remained in Korea for several years until it was moved to Japan. The corps spent almost 40 years as an administrative command of the US Army forces there, overseeing administrative functions but no combat. It was finally deactivated and consolidated in 1994.
component of the force by providing command to reserve units. It was assigned a shoulder sleeve insignia shortly thereafter. Though the corps was not activated, it remained on the organizational rolls of the Army, to be called on when needed. On 1 October 1933, the corps was moved to the active duty roster, though it remained deactivated.
staging area in Washington, responsible for training Army National Guard
forces in addition to its responsibilities training active duty and reserve units.
Following the Japanese attack on Pearl Harbor in late 1941, IX Corps was assigned to defensive duties on the West Coast
of the United States, specifically the central and northern regions of the coast. The Corps oversaw defenses on the West Coast for the majority of the war, but in 1944 it was moved to Fort McPherson
, Georgia in preparation for deployment overseas.
. On 25 September 1944, the corps closed headquarters at Fort McPherson and moved to Hawaii. When it arrived in Hawaii, IX Corps was put under the command of the Tenth United States Army. Under the Tenth Army, IX Corps was assigned two missions. In 1944, it was primarily concerned with formulating plans for an invasion of the coastal regions of Japanese-held China. Later in 1944 and early 1945, it was placed in charge of preparing the rest of the Tenth Army for movement to Okinawa in preparation for an invasion of the island
, which was launched in April 1945.
When General of the Army
Douglas MacArthur
took overall command of Pacific Forces, IX Corps was moved to Leyte
in the Philippine Islands and was assigned to the Sixth United States Army in July 1945. In Leyte, the corps was tasked with the planning of Operation Downfall
, the invasion of mainland Japan, specifically the island of Kyushu
. It was also tasked with planning occupation once Japan surrendered. IX Corps was assigned as one of four Corps under the command of the Sixth Army, with a strength of 14 divisions. With the 77th Infantry Division, the 81st Infantry Division and 98th Infantry Division, a force of 79,000 men, IX Corps would serve as the Sixth Army's reserve force during the initial invasion. Before the assault could be launched, Japan surrendered in August 1945, following the use of nuclear weapons on Hiroshima and Nagasaki
.
. IX Corps transferred its headquarters in October 1945 to Sapporo for occupation duties
. The next few years were a period during which the terms of the surrender were supervised and enforced; Japanese military installations and material were seized, troops were disarmed and discharged, and weapons of warfare disposed of. The duties of the occupation force included conversion of industry, repatriation of foreign nationals, and supervision of the complex features of all phases of Japanese government, economics, education, and industry.
As the occupation duties were accomplished, the occupation force continued to downsize as more troops returned home and their units were deactivated. By 1950, the Sixth Army had left Japan, and the occupation force was reduced to the Eighth United States Army commanding two corps and four under-strength divisions; the I Corps, commanding the 24th Infantry Division and 25th Infantry Division, and the IX Corps, commanding the 1st Cavalry Division and the 7th Infantry Division. IX Corps had been moved to Sendai as the occupation forces shifted as a result of the downsizing. As part of further downsizing, IX Corps was deactivated on 28 March 1950, and its command responsibilities were consolidated with other units.
began, and units from Japan began streaming into South Korea
. The Eighth Army, taking charge of the conflict, requested the activation of three corps headquarters for its growing command of UN forces. IX Corps was activated on 10 August 1950 at Fort Sheridan, Illinois
. Most of its personnel were transferred from the headquarters of the Fifth United States Army.
IX Corps arrived at the Pusan Perimeter in Korea on 22 September 1950, and became operational the next day when it took command of the 2nd Infantry Division and 25th Infantry Division. It took charge of the western flank of the perimeter, defending the Naktong River area against attacking North Korean units.
Amphibious landings at Inchon
by X Corps hit North Korean forces from behind, allowing I Corps and IX Corps to break out of Pusan, I Corps to the north and IX Corps to the south. Four days later I Corps troops pushed northward against crumbling enemy opposition to establish contact with forces of the 7th Infantry Division driving southward from the beachhead. Major elements of the North Korean Army were destroyed and cut off in this aggressive penetration; the link-up was effected south of Suwon
on 26 September. The offensive was continued northwards, past Seoul
, and across the 38th Parallel
on 1 October. The momentum of the attack was maintained, and the race to the North Korean capitol, Pyongyang
, ended on 19 October when elements of the South Korean 1st Infantry Division
and US 1st Cavalry Division both entered the city. The advance continued, but against unexpectedly stiffening enemy resistance. On 25 October the first Chinese prisoners on the Eighth Army front were taken by I Corps troops. By the end of October the city of Chongju, forty miles from the Yalu River
border of North Korea, had been captured. IX Corps advanced in the center of the Army, with I Corps along the west coast and X Corps operating independently further east. Commanders hoped the offensive would end the war "by Christmas."
, was overwhelmed from all sides by Chinese forces of the 40th CPV Army Corps
, and elements from the 38th CPV Army Corps
on 29 November in the Battle of Kunuri. By 1 December, the division was almost completely destroyed; it lost virtually all of its heavy equipment and vehicles, as well as suffering 4,940 men killed or missing. The 25th Infantry Division, on its western flank, was also hit by overwhelming Chinese forces of the 39th CPV Army Corps
, facing strong attacks and suffering heavy casualties and losses in equipment. However, it was spared the same losses as the 2nd Infantry Division by escaping across the Chongchon River. The Eighth Army suffered heavy casualties, ordering a complete withdraw to the Imjin River
, south of the 38th parallel, having been devastated by the overwhelming Chinese force. IX Corps retreated along the western coast to safety via Anju
.
In the wake of the retreat, the disorganized Eighth Army regrouped and re-formed. The 2nd and 25th Infantry Divisions had suffered so many losses that both divisions were designated combat ineffective, and were relegated to the Eighth Army's reserve to rebuild. IX Corps was then assigned the 1st Cavalry Division, 24th Infantry Division, 1st Marine Division and South Korean 6th Infantry Division
, as well as the 187th Airborne Regimental Combat Team. The corps' American forces were also reinforced at this point with battalions from Greece
and the Philippines
, as well as the 27th Commonwealth Brigade.
On 1 January 1951, 500,000 Chinese troops attacked the Eighth Army's line at the Imjin River, forcing them back 50 miles and allowing the Chinese to capture Seoul. The Chinese eventually advanced too far for their supply lines to adequately support them, and their attack stalled. The Eighth Army, battered by the Chinese assault, began to prepare spring offensives to retake lost ground and keep the retreating Chinese forces from being able to rest.
Following the establishment of defenses south of the capital city, General Matthew B. Ridgway ordered I, IX, and X Corps to conduct a general counteroffensive against the Chinese forces on 25 January, Operation Thunderbolt. The three corps advanced north with IX Corps at the center of the line, on both sides of the Han River
. The corps were to advance steadily northward, protected by heavy artillery and close air support, until they captured Seoul. IX Corps was tasked with capturing Chipyong-ni, southeast of Seoul while providing support to the other two corps. However, it encountered stiff resistance from Chinese forces dug in to the hilly country around Chipyong-ni and was still bogged down in combat by 2 February. Chinese forces had established machine gun nests in the hillside and mined roads to slow the corps' advance. In response, X Corps launched Operation Roundup
, hoping to take pressure off of IX Corps and to force the Chinese to abandon Seoul.
Between February and March, the Corps participated in Operation Killer
, pushing Chinese forces north of the Han River. This operation was quickly followed up with Operation Ripper
, which retook Seoul in March. After this, Operations Rugged and Dauntless in April saw Eighth Army forces advance north of the 38th parallel and reestablish themselves along the Kansas Line and Utah Line, respectively. In March, the 187th Airborne Regimental Combat Team and the 1st Marine Division were reassigned, and the corps was given command of the 7th Infantry Division and the South Korean 2nd Infantry Division
in their place.
In late April, the Chinese launched a major counterattack. 486,000 Chinese troops assaulted I Corps and IX Corps' sector of the lines. Most of the UN forces were able to hold their ground, but the Chinese broke through at Kapyong, where the South Korean 6th Division was destroyed by the 13th CPV Army Corps, which penetrated the line and threatened to encircle the American divisions to the west. The 1st Marine Division and 27th British Commonwealth Brigade were able to drive the 13th Army Corps back while the 24th and 25th Divisions withdrew on 25 April. The line was pushed back to Seoul but managed to hold. A second offensive the next month was similarly unsuccessful, as Chinese and North Korean forces suffered heavy casualties but were unable to push back the Eighth Army forces. The I and IX Corps had blunted the offensive at the No Name Line, just north of Seoul.
. Flanked by the South Korean 2nd and 6th Divisions, the 24th advanced past Kumwha, engaging the 20th and 27th CPV Armies. These attacks were fierce, though enemy resistance was not as strong as it had been in previous offensives. In November, the Chinese attempted to counter this attack, but were unsuccessful. It was at this point, after several successive counteroffensives that saw both sides fighting intensely over the same ground, that the two sides started serious peace negotiations. In January 1952, IX Corps was again reorganized, now containing the 7th Infantry Division and the newly-arrived 45th Infantry Division. Two months later, it was reorganized with the 2nd Infantry Division, the 40th Infantry Division, and the South Korean 2nd, 3rd, and Capital Divisions.
In October 1952, Chinese forces conducted a large offensive against IX Corps' sector, against the hilly countryside around the Iron Triangle
region of Chorwon
, Kumhwa, and Pyongyang
. The 38th CPV Field Army sent heavy assaults against the South Korean forces guarding Hill 395 in the Battle of White Horse
. At the same time, Chinese forces attacked Arrowhead Hill, which was held by the 2nd Infantry Division two miles away. Both hills changed hands several times, but after two weeks and almost 10,000 casualties, the Chinese were unsuccessful in capturing either objective and withdrew.
On 14 October 1952, IX Corps launched an offensive, Operation Showdown, intended to improve its defensive lines by capturing a complex of hills and force Chinese lines back. This complex included Pike's Peak, Jane Russell Hill, Sandy Hill, and Triangle Hill, northeast of Kumhwa. The 7th Infantry Division advanced, encountering resistance from the 15th Chinese Field Army. In the ensuing Battle of Triangle Hill
, the four hills were captured and recaptured by both sides several times in the heaviest fighting that year. Eventually, the UN forces withdrew having been unsuccessful in capturing their objectives. UN forces suffered 9,000 killed and the Chinese suffered 19,000 killed or wounded during the fighting. The result of the battle had only been a slight improvement in IX Corps' positions, as Chinese positions had been too well fortified for the UN forces to take and hold the ground. For the remainder of the year, US and Chinese forces both conducted a series of smaller raids on each others lines, avoiding major conflicts, as armistice negotiations continued unsuccessfully. In November, the Chinese launched another offensive to retake ground lost during these operations, which was again repulsed by UN forces.
In January 1953, IX Corps was reorganized for the last time and now consisted entirely of South Korean forces. It retained command of the South Korean 3rd Infantry Division and Capital Division, and gained command of the South Korean 9th Infantry Division
. The corps maintained a position around Chorwon, flanked to the west by I Corps and to the east by the South Korean II Corps. Though the South Korean II Corps saw a major attack against its lines in July 1953, IX Corps and its divisions only fought in limited engagements, usually with company-sized formations attacking or defending fortified positions against the Chinese until the end of the war. No major attacks against the corps were conducted through 1953, until the armistice was signed in July, ending the war.
In 1961, part of the IX Corps was split into the 9th Regional Support Command, subordinate to the US Army Pacific command. Though the 9th Regional Support Command was an independent unit, it continued to operate closely with IX Corps. It received a distinctive unit insignia
in 1969. In 1972, following further consolidation of US forces in the area, the US Army command on the Ryukyus was disbanded, and IX Corps merged with United States Army Japan to form a consolidated command of all US forces in the western Pacific region. There, its responsibilities included administrative oversight of US forces as well as conducting training and exercises with US and other units in the region.
For the next 20 years, IX Corps remained in the region conducting training and oversight to US Army forces in the area, and as such it was never deployed to support any other US Army contingencies. IX Corps remained a command component of United States Army Japan until 1994, when it was deactivated. At this point, the lineage of the Corps was assumed by the 9th Theater Army Area Command, which was activated in its place.
for service in World War II
, and nine campaign streamers and two unit decorations during its service in the Korean War
for a total of ten streamers and two unit decorations in its operational history.
Corps
A corps is either a large formation, or an administrative grouping of troops within an armed force with a common function such as Artillery or Signals representing an arm of service...
of the United States Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
. For most of its operational history, IX Corps was headquartered in or around Japan and subordinate to US Army commands in the Far East.
Created following World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, the corps was not activated for use until just before World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
almost 20 years later. The Corps spent most of World War II in charge of defenses on the West Coast of the United States, before moving to Hawaii and Leyte
Leyte
Leyte is a province of the Philippines located in the Eastern Visayas region. Its capital is Tacloban City and occupies the northern three-quarters of the Leyte Island. Leyte is located west of Samar Island, north of Southern Leyte and south of Biliran...
to plan and organize operations for US forces advancing across the Pacific. Following the end of the war, IX Corps participated in the occupation of mainland Japan.
The Corps' only combat came in the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
. It is best known for its exploits as a senior command of the Eighth United States Army, commanding front line UN forces in numerous offensives and counteroffensives throughout the war. The corps served on the front lines for most of the conflict and took command of several combat divisions at a time. Following the end of the Korean War, IX Corps remained in Korea for several years until it was moved to Japan. The corps spent almost 40 years as an administrative command of the US Army forces there, overseeing administrative functions but no combat. It was finally deactivated and consolidated in 1994.
History
The IX Corps headquarters was first constituted on 29 July 1921 in the organized reserves, a new corps formation intended to compliment the existing corps commands in the active dutyActive duty
Active duty refers to a full-time occupation as part of a military force, as opposed to reserve duty.-Pakistan:The Pakistan Armed Forces are one of the largest active service forces in the world with almost 610,000 full time personnel due to the complex and volatile nature of Pakistan's...
component of the force by providing command to reserve units. It was assigned a shoulder sleeve insignia shortly thereafter. Though the corps was not activated, it remained on the organizational rolls of the Army, to be called on when needed. On 1 October 1933, the corps was moved to the active duty roster, though it remained deactivated.
World War II
The corps headquarters was finally activated on 24 October 1940 at Fort Lewis, Washington as part of a large buildup of the US Army in response to conflicts around the world. It immediately began training of combat units in preparation for deployment. One year later, IX Corps took command of the Camp MurrayCamp Murray
Camp Murray is located adjacent to Fort Lewis, Washington. It is home to the Washington National Guard, Washington State Guard and the Washington Air National Guard....
staging area in Washington, responsible for training Army National Guard
Army National Guard
Established under Title 10 and Title 32 of the U.S. Code, the Army National Guard is part of the National Guard and is divided up into subordinate units stationed in each of the 50 states, three territories and the District of Columbia operating under their respective governors...
forces in addition to its responsibilities training active duty and reserve units.
Following the Japanese attack on Pearl Harbor in late 1941, IX Corps was assigned to defensive duties on the West Coast
West Coast of the United States
West Coast or Pacific Coast are terms for the westernmost coastal states of the United States. The term most often refers to the states of California, Oregon, and Washington. Although not part of the contiguous United States, Alaska and Hawaii do border the Pacific Ocean but can't be included in...
of the United States, specifically the central and northern regions of the coast. The Corps oversaw defenses on the West Coast for the majority of the war, but in 1944 it was moved to Fort McPherson
Fort McPherson
Fort McPherson was a U.S. Army military base located in East Point, Georgia, on the southwest edge of the City of Atlanta, Ga. It was the headquarters for the U.S. Army Installation Management Command, Southeast Region; the U.S. Army Forces Command; the U.S. Army Reserve Command; the U.S...
, Georgia in preparation for deployment overseas.
Planning
The Corps trained at Fort McPherson in preparation for deployment to the Pacific Theater of OperationsPacific Theater of Operations
The Pacific Theater of Operations was the World War II area of military activity in the Pacific Ocean and the countries bordering it, a geographic scope that reflected the operational and administrative command structures of the American forces during that period...
. On 25 September 1944, the corps closed headquarters at Fort McPherson and moved to Hawaii. When it arrived in Hawaii, IX Corps was put under the command of the Tenth United States Army. Under the Tenth Army, IX Corps was assigned two missions. In 1944, it was primarily concerned with formulating plans for an invasion of the coastal regions of Japanese-held China. Later in 1944 and early 1945, it was placed in charge of preparing the rest of the Tenth Army for movement to Okinawa in preparation for an invasion of the island
Battle of Okinawa
The Battle of Okinawa, codenamed Operation Iceberg, was fought on the Ryukyu Islands of Okinawa and was the largest amphibious assault in the Pacific War of World War II. The 82-day-long battle lasted from early April until mid-June 1945...
, which was launched in April 1945.
When General of the Army
General of the Army
General of the Army is a military rank used in some countries to denote a senior military leader, usually a General in command of a nation's Army. It may also be the title given to a General who commands an Army in the field....
Douglas MacArthur
Douglas MacArthur
General of the Army Douglas MacArthur was an American general and field marshal of the Philippine Army. He was a Chief of Staff of the United States Army during the 1930s and played a prominent role in the Pacific theater during World War II. He received the Medal of Honor for his service in the...
took overall command of Pacific Forces, IX Corps was moved to Leyte
Leyte
Leyte is a province of the Philippines located in the Eastern Visayas region. Its capital is Tacloban City and occupies the northern three-quarters of the Leyte Island. Leyte is located west of Samar Island, north of Southern Leyte and south of Biliran...
in the Philippine Islands and was assigned to the Sixth United States Army in July 1945. In Leyte, the corps was tasked with the planning of Operation Downfall
Operation Downfall
Operation Downfall was the Allied plan for the invasion of Japan near the end of World War II. The operation was cancelled when Japan surrendered after the atomic bombing of Hiroshima and Nagasaki and the Soviet Union's declaration of war against Japan. The operation had two parts: Operation...
, the invasion of mainland Japan, specifically the island of Kyushu
Kyushu
is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include , , and . The historical regional name is referred to Kyushu and its surrounding islands....
. It was also tasked with planning occupation once Japan surrendered. IX Corps was assigned as one of four Corps under the command of the Sixth Army, with a strength of 14 divisions. With the 77th Infantry Division, the 81st Infantry Division and 98th Infantry Division, a force of 79,000 men, IX Corps would serve as the Sixth Army's reserve force during the initial invasion. Before the assault could be launched, Japan surrendered in August 1945, following the use of nuclear weapons on Hiroshima and Nagasaki
Atomic bombings of Hiroshima and Nagasaki
During the final stages of World War II in 1945, the United States conducted two atomic bombings against the cities of Hiroshima and Nagasaki in Japan, the first on August 6, 1945, and the second on August 9, 1945. These two events are the only use of nuclear weapons in war to date.For six months...
.
Occupation
Following the surrender, IX Corps was assigned command of occupation forces on the northern island of HokkaidōHokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
. IX Corps transferred its headquarters in October 1945 to Sapporo for occupation duties
Occupied Japan
At the end of World War II, Japan was occupied by the Allied Powers, led by the United States with contributions also from Australia, India, New Zealand and the United Kingdom. This foreign presence marked the first time in its history that the island nation had been occupied by a foreign power...
. The next few years were a period during which the terms of the surrender were supervised and enforced; Japanese military installations and material were seized, troops were disarmed and discharged, and weapons of warfare disposed of. The duties of the occupation force included conversion of industry, repatriation of foreign nationals, and supervision of the complex features of all phases of Japanese government, economics, education, and industry.
As the occupation duties were accomplished, the occupation force continued to downsize as more troops returned home and their units were deactivated. By 1950, the Sixth Army had left Japan, and the occupation force was reduced to the Eighth United States Army commanding two corps and four under-strength divisions; the I Corps, commanding the 24th Infantry Division and 25th Infantry Division, and the IX Corps, commanding the 1st Cavalry Division and the 7th Infantry Division. IX Corps had been moved to Sendai as the occupation forces shifted as a result of the downsizing. As part of further downsizing, IX Corps was deactivated on 28 March 1950, and its command responsibilities were consolidated with other units.
Korean War
Only a few months later, the Korean WarKorean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
began, and units from Japan began streaming into South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
. The Eighth Army, taking charge of the conflict, requested the activation of three corps headquarters for its growing command of UN forces. IX Corps was activated on 10 August 1950 at Fort Sheridan, Illinois
Fort Sheridan, Illinois
Fort Sheridan is a residential neighborhood spread among Lake Forest, Highwood, and Highland Park in Lake County, Illinois, United States. It was originally established as a United States Army Post named after Civil War Cavalry General Philip Sheridan, to honor his services to Chicago...
. Most of its personnel were transferred from the headquarters of the Fifth United States Army.
Pusan Perimeter
Amphibious landings at Inchon
Battle of Inchon
The Battle of Inchon was an amphibious invasion and battle of the Korean War that resulted in a decisive victory and strategic reversal in favor of the United Nations . The operation involved some 75,000 troops and 261 naval vessels, and led to the recapture of the South Korean capital Seoul two...
by X Corps hit North Korean forces from behind, allowing I Corps and IX Corps to break out of Pusan, I Corps to the north and IX Corps to the south. Four days later I Corps troops pushed northward against crumbling enemy opposition to establish contact with forces of the 7th Infantry Division driving southward from the beachhead. Major elements of the North Korean Army were destroyed and cut off in this aggressive penetration; the link-up was effected south of Suwon
Suwon
Suwon is the provincial capital of Gyeonggi-do, South Korea. A major city of over a million inhabitants, Suwon lies approximately south of Seoul. It is traditionally known as "The City of Filial Piety"....
on 26 September. The offensive was continued northwards, past Seoul
Seoul
Seoul , officially the Seoul Special City, is the capital and largest metropolis of South Korea. A megacity with a population of over 10 million, it is the largest city proper in the OECD developed world...
, and across the 38th Parallel
38th parallel north
The 38th parallel north is a circle of latitude that is 38 degrees north of the Earth's equatorial plane. It crosses Europe, the Mediterranean Sea, Asia, the Pacific Ocean, North America, and the Atlantic Ocean...
on 1 October. The momentum of the attack was maintained, and the race to the North Korean capitol, Pyongyang
Pyongyang
Pyongyang is the capital of the Democratic People's Republic of Korea, commonly known as North Korea, and the largest city in the country. Pyongyang is located on the Taedong River and, according to preliminary results from the 2008 population census, has a population of 3,255,388. The city was...
, ended on 19 October when elements of the South Korean 1st Infantry Division
1st Infantry Division (South Korea)
The 1st Infantry Division is a military formation of the Republic of Korea Army's I Corps. The division was established on 12 May 1945 under the command of Colonel Suk-won Kim. It is based around three infantry regiments:The division was the first units of the ROK Army to be attacked by the North...
and US 1st Cavalry Division both entered the city. The advance continued, but against unexpectedly stiffening enemy resistance. On 25 October the first Chinese prisoners on the Eighth Army front were taken by I Corps troops. By the end of October the city of Chongju, forty miles from the Yalu River
Yalu River
The Yalu River or the Amnok River is a river on the border between North Korea and the People's Republic of China....
border of North Korea, had been captured. IX Corps advanced in the center of the Army, with I Corps along the west coast and X Corps operating independently further east. Commanders hoped the offensive would end the war "by Christmas."
Chinese intervention
On 27 November, China entered the war on the side of North Korea against the UN. Massed Chinese attacks were immediately launched against troops of the corps, with Chinese forces penetrating the corps' rear from its exposed east flank. The 2nd Infantry Division, at the front of IX Corp's advance in KunuriKunuri
Kunu-ri is a village located in South Pyongan Province, North Korea. A key battle of the Korean War, the Battle of Kunu-ri, took place there in November 1950. Kunu-ri was mainly a communication center and a railroad station at the time, and it contains the lateral east-west road which runs from...
, was overwhelmed from all sides by Chinese forces of the 40th CPV Army Corps
40th Army (People's Republic of China)
The 40th Army was a military formation of the People's Volunteer Army during the Korean War. It was composed of the 118th, 119th, and 120th Divisions.-History:In the morning of Oct...
, and elements from the 38th CPV Army Corps
38th Army (People's Republic of China)
The 38th Mechanized Group Army is a military formation of China's People's Liberation Army and one of three active group armies belonging to the Beijing Military Region...
on 29 November in the Battle of Kunuri. By 1 December, the division was almost completely destroyed; it lost virtually all of its heavy equipment and vehicles, as well as suffering 4,940 men killed or missing. The 25th Infantry Division, on its western flank, was also hit by overwhelming Chinese forces of the 39th CPV Army Corps
39th Army (People's Republic of China)
The 39th Army is a group army, a formation of roughly corps strength, of the People's Liberation Army.The Army was a military formation of the People's Volunteer Army during the Korean War...
, facing strong attacks and suffering heavy casualties and losses in equipment. However, it was spared the same losses as the 2nd Infantry Division by escaping across the Chongchon River. The Eighth Army suffered heavy casualties, ordering a complete withdraw to the Imjin River
Imjin River
The Imjin River is a river of North and South Korea. It flows from North to South, crossing the Demilitarized Zone and joining the Han River downstream of Seoul, very near the Yellow Sea.- History :...
, south of the 38th parallel, having been devastated by the overwhelming Chinese force. IX Corps retreated along the western coast to safety via Anju
Anju (city)
Anju-si is a city in the South Pyongan province of North Korea at the coordinates of . Its current population is unknown, but judging from satellite imagery, at least 100,000 people reside there. The Ch'ongch'on River passes through Anju....
.
6th Infantry Division (South Korea)
-History:The 6th Infantry Division was a military formation of the Republic of Korea Army during the 20th Century. The Division consisted of the 2nd, 7th, and 19th Regiments....
, as well as the 187th Airborne Regimental Combat Team. The corps' American forces were also reinforced at this point with battalions from Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
and the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, as well as the 27th Commonwealth Brigade.
On 1 January 1951, 500,000 Chinese troops attacked the Eighth Army's line at the Imjin River, forcing them back 50 miles and allowing the Chinese to capture Seoul. The Chinese eventually advanced too far for their supply lines to adequately support them, and their attack stalled. The Eighth Army, battered by the Chinese assault, began to prepare spring offensives to retake lost ground and keep the retreating Chinese forces from being able to rest.
Han River (Korea)
The Han River is a major river in South Korea and the fourth longest river on the Korean peninsula after the Amnok, Duman, and Nakdong rivers. It is formed by the confluence of the Namhan River , which originates in Mount Daedeok, and the Bukhan River , which originates on the slopes of Mount...
. The corps were to advance steadily northward, protected by heavy artillery and close air support, until they captured Seoul. IX Corps was tasked with capturing Chipyong-ni, southeast of Seoul while providing support to the other two corps. However, it encountered stiff resistance from Chinese forces dug in to the hilly country around Chipyong-ni and was still bogged down in combat by 2 February. Chinese forces had established machine gun nests in the hillside and mined roads to slow the corps' advance. In response, X Corps launched Operation Roundup
Operation Roundup (1951)
Operation Roundup was an attack launched on 5 February 1951, during the Korean War.The attack was launched by the United States X Corps toward Hongch'on and P'yonch'ang....
, hoping to take pressure off of IX Corps and to force the Chinese to abandon Seoul.
Between February and March, the Corps participated in Operation Killer
Operation Killer
Operation Killer was the start of the second major counter offensive launched by United Nations forces against the People's Volunteer Army and the North Korean Army during the Korean War between 20 February and 6 March 1951...
, pushing Chinese forces north of the Han River. This operation was quickly followed up with Operation Ripper
Operation Ripper
Operation Ripper was a United Nations military operation conceived by the commander US Eighth Army, General Matthew B. Ridgway, during the Korean War. The operation was intended to destroy as much as possible of the Chinese communist People's Volunteer Army and North Korean military around Seoul...
, which retook Seoul in March. After this, Operations Rugged and Dauntless in April saw Eighth Army forces advance north of the 38th parallel and reestablish themselves along the Kansas Line and Utah Line, respectively. In March, the 187th Airborne Regimental Combat Team and the 1st Marine Division were reassigned, and the corps was given command of the 7th Infantry Division and the South Korean 2nd Infantry Division
2nd Infantry Division (South Korea)
The 2nd Infantry Division is a military formation of the Republic of Korea Army . It was formed during the Korean War and was part of the defensive line in the Third Battle of Seoul....
in their place.
In late April, the Chinese launched a major counterattack. 486,000 Chinese troops assaulted I Corps and IX Corps' sector of the lines. Most of the UN forces were able to hold their ground, but the Chinese broke through at Kapyong, where the South Korean 6th Division was destroyed by the 13th CPV Army Corps, which penetrated the line and threatened to encircle the American divisions to the west. The 1st Marine Division and 27th British Commonwealth Brigade were able to drive the 13th Army Corps back while the 24th and 25th Divisions withdrew on 25 April. The line was pushed back to Seoul but managed to hold. A second offensive the next month was similarly unsuccessful, as Chinese and North Korean forces suffered heavy casualties but were unable to push back the Eighth Army forces. The I and IX Corps had blunted the offensive at the No Name Line, just north of Seoul.
Stalemate
In September, the UN Forces launched another counteroffensive with the 24th Infantry Division at the center of the line, west of the Hwachon Reservoir. Three of I Corps divisions advanced behind the 24th Infantry Division in Operation CommandoOperation Commando (1951)
Operation Commando was an offensive undertaken by UN forces during the Korean War between 2–5 October 1951. The U.S. I Corps seized the Jamestown Line, destroying elements of the 42nd, 47th, 64th and 65th Chinese Armies. This prevented the Communist forces from interdicting the U.N...
. Flanked by the South Korean 2nd and 6th Divisions, the 24th advanced past Kumwha, engaging the 20th and 27th CPV Armies. These attacks were fierce, though enemy resistance was not as strong as it had been in previous offensives. In November, the Chinese attempted to counter this attack, but were unsuccessful. It was at this point, after several successive counteroffensives that saw both sides fighting intensely over the same ground, that the two sides started serious peace negotiations. In January 1952, IX Corps was again reorganized, now containing the 7th Infantry Division and the newly-arrived 45th Infantry Division. Two months later, it was reorganized with the 2nd Infantry Division, the 40th Infantry Division, and the South Korean 2nd, 3rd, and Capital Divisions.
In October 1952, Chinese forces conducted a large offensive against IX Corps' sector, against the hilly countryside around the Iron Triangle
Iron Triangle (Korea)
The Iron Triangle was a key communist Chinese and North Korean concentration area and communications junction during the Korean War, located in the central sector between Chorwon and Kumwha in the south and Pyonggang in the north...
region of Chorwon
Chorwon
Chorwon is a kun, or county, in Kangwon province, North Korea. Portions of it were once a single county together with the county of the same name in South Korea; other portions were added from neighboring counties in the 1956 reorganization of local governments...
, Kumhwa, and Pyongyang
Pyongyang
Pyongyang is the capital of the Democratic People's Republic of Korea, commonly known as North Korea, and the largest city in the country. Pyongyang is located on the Taedong River and, according to preliminary results from the 2008 population census, has a population of 3,255,388. The city was...
. The 38th CPV Field Army sent heavy assaults against the South Korean forces guarding Hill 395 in the Battle of White Horse
Battle of White Horse
The Battle of White Horse , was another in a series of bloody battles for dominant hilltop positions during the Korean War. Baengma-goji was a hill in the Iron Triangle, formed by Pyonggang at its peak and Kumhwa and Chorwon at its base, was a strategic transportation route in the central region...
. At the same time, Chinese forces attacked Arrowhead Hill, which was held by the 2nd Infantry Division two miles away. Both hills changed hands several times, but after two weeks and almost 10,000 casualties, the Chinese were unsuccessful in capturing either objective and withdrew.
Battle of Triangle Hill
The Battle of Triangle Hill, also known as Operation Showdown or the Shangganling Campaign ,Chinese sources often mistranslate Shangganling Campaign as the Battle of Heartbreak Ridge. was a protracted military engagement during the Korean War...
, the four hills were captured and recaptured by both sides several times in the heaviest fighting that year. Eventually, the UN forces withdrew having been unsuccessful in capturing their objectives. UN forces suffered 9,000 killed and the Chinese suffered 19,000 killed or wounded during the fighting. The result of the battle had only been a slight improvement in IX Corps' positions, as Chinese positions had been too well fortified for the UN forces to take and hold the ground. For the remainder of the year, US and Chinese forces both conducted a series of smaller raids on each others lines, avoiding major conflicts, as armistice negotiations continued unsuccessfully. In November, the Chinese launched another offensive to retake ground lost during these operations, which was again repulsed by UN forces.
In January 1953, IX Corps was reorganized for the last time and now consisted entirely of South Korean forces. It retained command of the South Korean 3rd Infantry Division and Capital Division, and gained command of the South Korean 9th Infantry Division
9th Infantry Division (South Korea)
The 9th Infantry Division , also known as White Horse after the victory of Battle of White Horse, is an infantry division of the Republic of Korea Army...
. The corps maintained a position around Chorwon, flanked to the west by I Corps and to the east by the South Korean II Corps. Though the South Korean II Corps saw a major attack against its lines in July 1953, IX Corps and its divisions only fought in limited engagements, usually with company-sized formations attacking or defending fortified positions against the Chinese until the end of the war. No major attacks against the corps were conducted through 1953, until the armistice was signed in July, ending the war.
After Korea
Following the armistice, IX Corps remained on the front lines in Korea in case hostilities erupted again. On 1 January 1954, it was reassigned from the Eighth Army to the Far East United States Army Forces. In November 1956, over three years after the signing of the armistice, IX Corps headquarters left the front lines, moving to Fort Buckner, Okinawa, and the divisions under its command were shifted to the command of other headquarters. There, as a part of consolidation of US forces in the region, IX Corps merged with the US Army's Ryukyus command to form a joint command element on 1 January 1957. The command oversaw administrative duties of US forces in the Ryukyu Islands area.In 1961, part of the IX Corps was split into the 9th Regional Support Command, subordinate to the US Army Pacific command. Though the 9th Regional Support Command was an independent unit, it continued to operate closely with IX Corps. It received a distinctive unit insignia
Distinctive unit insignia
A Distinctive Unit Insignia is a metal heraldic device worn by soldiers in the United States Army. The DUI design is derived from the coat of arms authorized for a unit...
in 1969. In 1972, following further consolidation of US forces in the area, the US Army command on the Ryukyus was disbanded, and IX Corps merged with United States Army Japan to form a consolidated command of all US forces in the western Pacific region. There, its responsibilities included administrative oversight of US forces as well as conducting training and exercises with US and other units in the region.
For the next 20 years, IX Corps remained in the region conducting training and oversight to US Army forces in the area, and as such it was never deployed to support any other US Army contingencies. IX Corps remained a command component of United States Army Japan until 1994, when it was deactivated. At this point, the lineage of the Corps was assumed by the 9th Theater Army Area Command, which was activated in its place.
Honors
The IX Corps was awarded one campaign streamerCampaign streamer
Campaign streamers are decorations attached to military flags to recognize particular achievements or events of a military unit or service. Attached to the headpiece of the assigned flag, the streamer often is an inscribed ribbon with the name and date denoting participation in a particular battle,...
for service in World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, and nine campaign streamers and two unit decorations during its service in the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
for a total of ten streamers and two unit decorations in its operational history.
Unit decorations
| Ribbon | Award | Year | Notes |
|---|---|---|---|
.svg.png) |
Republic of Korea Presidential Unit Citation | 1950 | for service in Korea |
|
Republic of Korea Presidential Unit Citation | 1952–1953 | for service in Korea |
Campaign streamers
| Conflict | Streamer | Year(s) |
|---|---|---|
| World War II World War II World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis... |
Asiatic Pacific Theater | (No inscription) |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
UN Offensive | 1950 |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
CCF Intervention | 1950 |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
First UN Counteroffensive | 1950 |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
CCF Spring Offensive | 1951 |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
UN Summer-Fall Offensive | 1951 |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
Second Korean Winter | 1951–1952 |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
Korea, Summer-Fall 1952 | 1952 |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
Third Korean Winter | 1952–1953 |
| Korean War Korean War The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union... |
Korea, Summer 1953 | 1953 |