The Battle of Chosin Reservoir, also known as the Chosin Reservoir Campaign or the Battle of Lake Changjin (Korean: 장진호 전투; Hanja: 長津湖戰鬪; MR: Changjinho chŏnt'u), was a battle in the Korean War. The name "Chosin" is derived from the Japanese pronunciation "Chōshin", instead of the Korean pronunciation.
The battle took place about a month after the People's Republic of China entered the conflict and sent the 9th Corps of the People's Volunteer Army (PVA) to infiltrate the northeastern part of North Korea. On 27 November 1950, the Chinese force surprised the US X Corps commanded by Major General Edward Almond in the Chosin Reservoir area. Between 27 November and 13 December, 30,000 United Nations Command troops, later nicknamed "The Chosin Few", under the field command of Major General Oliver P. Smith were encircled and attacked by about 120,000 Chinese troops under the command of Song Shilun, who had been ordered by Mao Zedong to destroy the UN forces.
In the ensuing 17-day battle in freezing weather that followed, the UN forces were able to break out of the encirclement and withdraw to the port of Hungnam in what U.S. historians described as the "greatest evacuation movement by sea in U.S. military history". Both sides suffered severe casualties, with battle casualties and non-battle casualties caused by the frigid weather. The withdrawal of the US Eighth Army from northwest Korea and its recovery by Chinese forces in the aftermath of the Battle of the Ch'ongch'on River and the evacuation of the X Corps from the port of Hungnam in northeast Korea marked the withdrawal of UN troops from North Korea.
The battle therefore produced a complex military outcome: Chinese forces held the battlefield and forced X Corps from northeastern Korea, but X Corps withdrew most of its forces as an effective fighting formation, while the Chinese 9th Corps suffered losses severe enough to keep it out of action for about three months.
Background
By mid-October 1950, after the successful landing at Inchon by the US X Corps, the Eighth Army breakout from the Pusan Perimeter and the subsequent pursuit and destruction of the Korean People's Army (KPA), the Korean War appeared to be all but over. United Nations (UN) forces advanced rapidly into North Korea with the intention of reuniting North and South Korea before the end of 1950. North Korea is divided down the middle by the impassable Taebaek Mountains, which separated the UN forces into two groups. The US Eighth Army advanced north through the western coast of the Korean Peninsula, while the Republic of Korea (ROK) I Corps and the US X Corps advanced north on the eastern coast.
At the same time the People's Republic of China entered the conflict after issuing several warnings to the United Nations. On 19 October 1950, large formations of Chinese troops, dubbed the People's Volunteer Army (PVA), secretly crossed the border and into North Korea. One of the first Chinese units to reach the Chosin Reservoir area was the PVA 42nd Army, which was to stop the eastern UN advances. On 25 October, the advancing ROK I Corps made contact with the Chinese and halted at Funchilin Pass (40°12′14″N 127°18′00″E / 40.204°N 127.3°E), south of the Chosin Reservoir.
After the landing at Wonsan, the US 1st Marine Division of X Corps engaged the defending PVA 124th Division on 2 November; the battle causing severe casualties to the Chinese. On 6 November, the PVA 42nd Corps ordered a retreat to the north with the intention of luring the UN forces to the Chosin Reservoir. By 24 November, the 1st Marine Division occupied both Sinhung-ni (40°33′25″N 127°16′12″E / 40.557°N 127.27°E) on the eastern side of the reservoir and Yudami-ni (40°28′48″N 127°06′43″E / 40.48°N 127.112°E) on the west side.
Faced with the sudden attacks by Chinese forces in the Eighth Army sector, General Douglas MacArthur ordered the Eighth Army to launch the Home-by-Christmas Offensive. To support the offensive, MacArthur ordered X Corps to attack west from the Chosin Reservoir and to cut the vital Manpojin—Kanggye—Huichon supply line. Major General Edward M. Almond, commander of the US X Corps, formulated a plan on 21 November. It called for the US 1st Marine Division to advance west through Yudami-ni, while the US 7th Infantry Division would provide a regimental combat team to protect the right flank at Sinhung-ni. The US 3rd Infantry Division would also protect the left flank, while providing security in the rear area. By then the X Corps was stretched thin along a 400 mi (640 km) front.
Surprised by the Marine landing at Wonsan, Chinese Communist Party chairman Mao Zedong called for the immediate destruction of the ROK Capital Division, ROK 3rd Infantry Division, US 1st Marine Division, and US 7th Infantry Division in a telegram to Commander Song Shilun of the 9th Corps, PVA, on 31 October. Under Mao's urgent orders, the 9th Corps was rushed into North Korea on 10 November. Undetected by UN intelligence, it entered the Chosin Reservoir area on 17 November, with the 20th Army of the 9th Corps relieving the 42nd Army near Yudami-ni.
Prelude
Location, terrain and weather
Chosin Reservoir is a man-made lake located in the northeast of the Korean peninsula. The name Chosin is the Japanese pronunciation of the Korean place name Changjin, and the name stuck due to the outdated Japanese maps used by UN forces. The battle's main focus was around the 78-mile-long (126 km) road that connects Hungnam and Chosin Reservoir, which served as the only retreat route for the UN forces. Through these roads, Yudami-ni and Sinhung-ni, located at the west and east side of the reservoir respectively, are connected at Hagaru-ri (now Changjin-ŭp) (40°23′02″N 127°14′56″E / 40.3838°N 127.249°E). From there, the road passes through Koto-ri (40°17′02″N 127°18′00″E / 40.284°N 127.3°E) and eventually leads to the port of Hungnam. The area around the Chosin Reservoir was sparsely populated.
The battle was fought over some of the roughest terrain during some of the harshest winter weather conditions of the Korean War. The road was created by cutting through the hilly terrain of Korea, with steep climbs and drops. Dominant peaks, such as the Funchilin Pass and the Toktong Pass (40°23′38″N 127°09′40″E / 40.3938°N 127.161°E), overlook the entire length of the road. The road's quality was poor, and in some places it was reduced to a one-lane gravel trail. On 14 November 1950, a cold front from Siberia descended over the Chosin Reservoir, and the temperature plunged, according to estimates, to as low as −36 °F (−38 °C). The cold weather created considerable danger of frostbite casualties and was accompanied by frozen ground, icy roads, and weapon malfunctions. Medical supplies froze; morphine syrettes had to be defrosted in a medic's mouth before they could be injected; blood plasma was frozen and useless on the battlefield. Even cutting off clothing to deal with a wound risked gangrene and frostbite. Batteries used for the Jeeps and radios did not function properly in the temperature and quickly ran down. The lubrication in the guns gelled and rendered them useless in battle. Likewise, the springs on the firing pins would not strike hard enough to fire the round, or would jam.
Forces and strategies
Although the 1st Marine Division landed at Wonsan as part of Almond's US X Corps, Almond and Major General Oliver P. Smith of the 1st Marine Division shared a mutual loathing of each other that dated back to a meeting before the landing at Inchon, when Almond had spoken of how easy amphibious landings are even though he had never been involved in one. Smith believed there were large numbers of Chinese forces in North Korea despite the fact that higher headquarters in Tokyo said otherwise, but Almond felt Smith was overly cautious. The mutual distrust between the commanders caused Smith to slow the 1st Marine Division's advance towards the Chosin Reservoir in violation of Almond's instructions. Smith established supply points and airfields along the way at Hagaru-ri and Koto-ri.
As the US X Corps was pushing towards the reservoir, the Chinese formulated their strategy, based on their experiences in the Chinese Civil War. Working from the assumption that only a light UN presence would be at the reservoir, the Chinese 9th Corps was first to destroy the UN garrisons at Yudami-ni and Sinhung-ni, then push towards Hagaru-ri. Believing the bulk of the US X Corps would move to rescue the destroyed units, the 9th Corps would then block and trap the main UN forces on the road between Hagaru-ri and Hungnam. The 9th Corps initially committed eight divisions for the battle, with most of the forces concentrated at Yudami-ni and Sinhung-ni.
The flaw in the Chinese plan was a lack of accurate intelligence about the UN forces. Even though the US X Corps was stretched thin over northeast Korea, the slow Marine advance allowed the bulk of the US 1st Marine Division, including the 5th, 7th and 11th Marines, to be concentrated at Yudami-ni. Furthermore, the strategically important Hagaru-ri, where a C-47-capable airfield was under construction and a supply dump, was not a priority for the Chinese despite being lightly defended by the 1st and 7th Marines. Only Regimental Combat Team 31 (RCT-31), an understrength and hastily formed regimental combat team of the US 7th Infantry Division, was thinly spread along the eastern bank of the reservoir. RTC-31 relieved the 5th Marines which had previously been on the east reservoir with 1st Battalion, 32nd Infantry arriving in the afternoon of November 25th, while 3rd Battalion, 31st Infantry and the 57th Field Artillery battalion only arrived late in the afternoon on November 27th. Those units later took the brunt of the Chinese assaults.
As for the UN forces, the 1st Marine Division had an effective strength of 25,473 men at the start of the battle, and it was further reinforced by the British Royal Marines unit 41 (Independent) Commando and the equivalent of two regiments from the 3rd and 7th Army Infantry Divisions. The UN forces had a combined strength of about 30,000 men during the course of the battle. The UN forces at Chosin were also supported by one of the greatest concentrations of air power during the Korean War, since the 1st Marine Aircraft Wing stationed at Yonpo Airfield and five aircraft carriers from the US Navy's Task Force 77 were able to launch 230 sorties daily to provide close air support during the battle, while the US Air Force Far East Combat Cargo Command in Japan reached the capacity of airdropping 250 tons of supplies per day to resupply the trapped UN forces.
Although the 9th Corps was one of China's elite formations, composed of veterans and former POWs from the Huaihai Campaign, several deficiencies hampered its ability during the battle. Initially the 9th Corps was intended to be outfitted in Manchuria during November, but Mao suddenly ordered it into Korea before that could happen. As a result, the 9th Corps had almost no winter clothing for the harsh Korean winter. Similarly, poor logistics forced the 9th Corps to abandon heavy artillery, while working with little food and ammunition. The food shortage forced the 9th Corps to initially station a third of its strength away from the Chosin Reservoir in reserve, and starvation and exposure weakened the Chinese units, since foraging was not an option in the sparsely populated area. By the end of the battle, more Chinese troops had died from the cold than from combat and air raids.
Chinese strength is usually estimated at 120,000 troops for the battle. Before arriving in Korea, the 9th Corps was also reinforced. Each of its three corps had four divisions instead of the regular three; thus it had 12 divisions, with 10,000 men per division. Infantry from two formerly "liberated" (surrendered) Nationalist divisions were absorbed to bring each infantry company up to strength. Some companies had approximately 150 men, while others were reinforced with more than 200 men. However, attrition due to UN air raids, poor logistics and cold weather had also taken a toll on the way to the battlefield. On the day 9th Corps entered Korea, for example, frostbite inflicted 700 casualties, while most of its transport vehicles were destroyed by UN air raids. During the course of the battle, Chinese prisoners of war reported that most of the 9th Corps' divisions had become under strength, numbering about 6,500 to 7,000 men per division. These factors, plus uncertainties over the Chinese order of battle in Western sources, led some historians to revise Chinese numbers down to as low as 60,000 during the course of battle.
Eventually, all 12 Chinese divisions of the 9th Corps were deployed, although the 78th and the 88th Divisions of the PVA 26th Army did not make contact with UN forces during the course of the battle. Eight divisions of the PVA 20th and 27th Armies served as the main attacking force. Four divisions of the PVA 26th Army initially were held back in reserve, and deployed after 20th and 27th Armies had exhausted all their available strength.
Battle
On the night of 27 November, the PVA 20th and 27th Armies of the 9th Corps launched multiple attacks and ambushes along the road between the Chosin Reservoir and Kot'o-ri. At Yudam-ni, the 5th, 7th and 11th Marines were surrounded and attacked by the PVA 79th and 89th Divisions, with the 59th Division attacking the road between Yudam-ni and Hagaru-ri to cut off communication. Similarly, RCT-31 was isolated and ambushed at Sinhung-ni by the PVA 80th and 81st Divisions. At Hagaru-ri, the 1st Marine Division command headquarters was targeted by the PVA 58th Division. Finally, the PVA 60th Division surrounded elements of the 1st Marines at Kot'o-ri from the north. Caught by complete surprise, the UN forces were cut off at Yudam-ni, Sinhung-ni, Hagaru-ri and Kot'o-ri by 28 November.