The Korean War (1950-1953) was a major proxy war of the Cold War fought between North Korea, backed by China and the Soviet Union, and South Korea, supported by the UN Command led by the United States. The conflict began when North Korean forces crossed the 38th parallel, the dividing line between the two nations, aiming to unify the Korean Peninsula under communist rule. The war saw intense fighting, involvement of numerous countries under the UN banner, and heavy casualties on both sides. Although an armistice was signed in 1953, a formal peace treaty was never reached, leaving the two Koreas technically still at war and divided along the Demilitarized Zone (DMZ). The Korean War significantly shaped the geopolitical landscape of East Asia and cemented the division of Korea.
1941: Korean Participation in Burma Campaign
Korean nationalist forces, backed by the Chinese Nationalists, participated in the Burma campaign against Japan starting in 1941.
1943: Tehran Conference
The Soviet Union affirmed its commitment to join the Pacific War against Japan after the victory in Europe at the Tehran Conference in 1943.
1944: Limited Helicopter Medevac Use in WWII
During 1944-1945, the YR-4 helicopter saw limited use for medical evacuations in World War II, foreshadowing its significant role in later conflicts.
February 1945: Yalta Conference Agreement on Soviet Entry into Pacific War
At the Yalta Conference in February 1945, the Soviet Union agreed to join the Pacific War against Japan.
August 1945: Soviet Entry into Korea
The Soviet Union entered Korea in August 1945, quickly occupying northern Korea following its declaration of war on Japan.
September 1945: US Military Control in South Korea
In September 1945, the US established military control over South Korea, with General Douglas MacArthur issuing Proclamation No. 1.
December 1945: Establishment of Joint Commission and Korean Unrest
In December 1945, a US-Soviet Joint Commission was formed to administer Korea, which led to unrest and riots among Koreans opposing the trusteeship plan.
1945: Division of Korea
After World War II in 1945, Korea was divided into two occupation zones along the 38th parallel by the Soviet Union and the United States.
1945: Industrial Capacity of Korea
In 1945, before the Korean War, North Korea held a significant advantage in industrial capacity, possessing 80% of Korea's heavy industry.
April 1948: Jeju Uprising
The Jeju uprising, which began in April 1948, was an uprising against the South Korean government. It resulted in a violent conflict and the deaths of thousands of people, including both civilians and rebels.
August 1948: Establishment of the Republic of Korea (South Korea)
The Republic of Korea (South Korea) was established in August 1948 after UN-supervised elections.
1948: Insurgency and Border War
A North Korea-backed insurgency and undeclared border war intensified in 1948, resulting in numerous casualties on both sides.
1948: Establishment of Communist Government in North Korea and Troop Withdrawals
In 1948, a communist government, led by Kim Il Sung, was established in North Korea. Both Soviet and US forces withdrew from the peninsula by 1949.
1948: Establishment of Separate Governments
Separate governments were established in North and South Korea in 1948, both claiming legitimacy over the entire peninsula and exacerbating the political divide.
1948: Berlin Blockade and Nuclear Deterrence
The deployment of nuclear-capable B-29 bombers to Britain in 1948-1949 was seen by many US officials as a contributing factor to the resolution of the Berlin Blockade.
March 1949: Kim Il-sung Seeks Support for Invasion
In March 1949, Kim Il-sung began seeking Stalin's support for an invasion of South Korea.
May 1949: Suppression of Uprisings
By May 1949, both the Jeju uprising and the Yeosu-Suncheon rebellion were suppressed by the South Korean government.
May 1949: Start of Border Clashes
Border clashes between North and South Korea began in May 1949, marking an escalation of tensions along the 38th parallel.
August 1949: Kuksa-bong Attack
In August 1949, thousands of North Korean troops attacked South Korean positions north of the 38th parallel, but were repulsed.
October 1949: ROKA Offensive
In October 1949, the ROKA (Republic of Korea Army) launched a major offensive against insurgents in South Cholla and Taegu.
1949: US Troop Withdrawal from South Korea
The US withdrew its forces from South Korea in 1949, after the establishment of separate governments in the North and South.
1949: Guerrilla Warfare and Infiltration
Throughout 1949, insurgent activity intensified in South Korea, supported by North Korean agents and army defectors. North Korea launched an offensive in September 1949 aimed at weakening the South Korean government.
1949: Chinese Support for North Korea
Throughout 1949, China provided extensive support to North Korea, including sending troops and equipment.
1949: Berlin Blockade and Nuclear Deterrence
The deployment of nuclear-capable B-29 bombers to Britain in 1948-1949 was seen by many US officials as a contributing factor to the resolution of the Berlin Blockade.
1949: PLA Troops Enter North Korea
In the fall of 1949, two divisions of the People's Liberation Army (PLA), primarily composed of Korean-Chinese soldiers, entered North Korea.
1949: North Korean Census and Military Strength
In 1949, the first official census revealed North Korea's population to be 9,620,000.
January 1950: Soviet Boycott of UN Security Council
The Soviet Union boycotted the UN Security Council meetings in January 1950 due to Taiwan's occupation of China's permanent seat.
March 1950: Suppression of Insurgency
By March 1950, the ROKA had significantly weakened the insurgency, killing or capturing thousands of guerrillas.
April 1950: Stalin Authorizes Invasion
In April 1950, Stalin granted Kim Il-sung permission to invade South Korea, provided that Mao Zedong would agree to send reinforcements if necessary.
May 1950: Kim Il-sung Secures Mao's Support
In May 1950, Kim Il-sung met with Mao Zedong and secured China's support for the planned invasion of South Korea, although there are differing interpretations of this meeting.
June 1950: Start of the Korean War and the Ongjin Peninsula Battle
On June 25, 1950, the Korean People's Army (KPA) crossed the 38th parallel, initiating the Korean War. Fighting began on the Ongjin Peninsula with disputed claims about who initiated the conflict.
June 1950: Start of the Korean War
The Korean War began in June 1950 when North Korea, supported by the Soviet Union and China, invaded South Korea.
June 1950: UN Security Council Resolutions and US Intervention
In June 1950, the UN Security Council condemned the North Korean invasion and recommended military assistance to South Korea. The US subsequently ordered its air and sea forces to intervene.
June 1950: Truman Orders Plans for Potential Soviet Attack
In June 1950, President Truman ordered the preparation of plans for attacking Soviet forces if they entered the Korean War.
June 1950: North Korea Proposes Elections and Revises War Plan
In June 1950, North Korea proposed all-Korea elections and later revised its war plan to launch a general attack across the 38th parallel.
June 1950: KPA Casualties and UN Troop Strength
By the end of June 1950, the KPA suffered significant casualties. The UN forces on the Korean peninsula reached substantial numbers.
June 1950: South Korean Military Status
As of June 1950, the South Korean army was ill-equipped and lacked essential weaponry, including tanks, compared to the North Korean forces.
June 1950: North Korean Invasion
On June 1950, the North Korean People's Army (KPA) invaded South Korea, marking the beginning of the Korean War.
July 1950: Naval Skirmish
In July 1950, a naval skirmish took place where a combined force of U.S. and Royal Navy ships engaged and sunk several North Korean torpedo boats and mortar gunboats. Days before the Battle of Incheon, the ROK ship PC-703 sunk a North Korean minelayer near Incheon and three supply ships in the Yellow Sea.
July 1950: Battle of Osan and Subsequent Retreats
In July 1950, the first significant US engagement, the Battle of Osan, resulted in a US defeat and subsequent retreats to Taejeon, which was later captured by the KPA.
August 1950: Jet Aircraft Dominance
By August 1950, the Korean War marked the first major conflict where jet aircraft dominated air combat. UN forces' jet fighters, such as the P-80 Shooting Star and F9F Panther, gained air superiority over the KPAF's propeller-driven aircraft, decimating their numbers.
August 1950: Proposed Election Date
North Korea set the proposed election dates for August 5-8, 1950.
August 1950: Tank Warfare in the Korean War
In August 1950, the Korean People's Army (KPA)'s initial success with Soviet T-34-85 tanks against the Republic of Korea (ROK) shifted. The UN forces countered with heavier tanks like the American M4A3 Sherman, M26 Pershing, and British Centurion, Churchill, and Cromwell tanks, causing significant KPA tank losses.
August 1950: US Congressional Funding for Korean War
In August 1950, the US Congress approved $12 billion for military action in Korea.
September 1950: Reinforcements and Pusan Perimeter Defense
By September 1950, the US reinforced the Pusan Perimeter, increasing troop numbers and tanks, and eventually outnumbering the KPA.
October 1950: China's Warning to the US
On October 3, 1950, China warned the US against crossing the Yalu River, but the warning was dismissed.
November 1950: US Orders for Potential Atomic Bombing
On November 5, 1950, the U.S. Joint Chiefs of Staff issued orders for a potential retaliatory atomic bombing of Manchurian bases if certain conditions were met.
November 1950: Start of Soviet Air Force Reporting Period
November 1950 marked the beginning of a reporting period for the Soviet air forces in Korea, documenting their claimed victories and losses in air combat.
November 1950: Chinese Intervention and the Battle of Unsan
In November 1950, Chinese forces entered the war, and the first confrontation with US troops occurred. The Battle of Unsan resulted in a significant defeat for the US forces.
November 1950: Truman Publicly Considers Nuclear Weapons
During a press conference on November 30, 1950, President Truman publicly stated that the use of nuclear weapons in Korea was under active consideration.
November 1950: KPA Tank Losses and Retreat
By November 1950, the Incheon landings disrupted KPA supply lines, forcing their retreat and the abandonment of numerous T-34 tanks and heavy weapons, leading to a decline in KPA armored engagements.
December 1950: USAF Deploys F-86 Sabres
In December 1950, the United States Air Force countered the MiG-15 threat by deploying F-86 Sabre jets, their most advanced fighters, to Korea.
December 1950: US Caution on Nuclear Weapons Use
In December 1950, despite the difficult military situation, the US government remained cautious about using nuclear weapons in Korea due to the risk of escalating the conflict.
1950: Reinforcement of the KPA
Throughout 1950, former PLA troops continued to reinforce the Korean People's Army (KPA).
1950: Stalin's Shift in Strategy
By 1950, Stalin's strategic outlook changed, leading him to believe that the conditions were favorable for a war in Korea. Several factors influenced his decision, including the communist victory in China, the US withdrawal from Korea, and the Soviet development of nuclear weapons.
1950: North Korean Military Buildup and Invasion
By mid-1950, North Korea had amassed a substantial military force, including infantry, tanks, and an air force, capturing various territories in South Korea.
1950: Decrease in Border Incidents
By the start of 1950, border incidents between North and South Korea had decreased.
1950: Continued Chinese and Soviet Support
During 1950, both China and the Soviet Union continued to provide military assistance to North Korea.
1950: Chinese Involvement in the Korean War
From 1950 to 1953, a significant portion of the Chinese military, including infantry, air force, tank, artillery, and railroad engineering units, was deployed to Korea. The financial strain of the war, estimated at over 10 billion yuan (roughly US$3.3 billion), plus $1.3 Billion owed to the USSR, represented a substantial portion of China's annual government budget.
1950: Unpreparedness of U.S. Forces
In 1950, Major General Floyd L. Parks criticized the unpreparedness of US forces deployed in the early stages of the Korean War, highlighting the challenges faced by ill-equipped and inadequately trained troops.
1950: U.S. Defense Policy and Early Setbacks
In 1950, U.S. Secretary of Defense Louis A. Johnson's adherence to Truman's defense budget cuts was blamed for the initial setbacks in Korea, with reports of poorly equipped and trained troops widespread in the war's early stages.
1950: Counterinsurgency and Infiltration Attempts
In 1950, counterinsurgency operations intensified in South Korea, while North Korea continued to send infiltrators to support the insurgency. However, these attempts were largely unsuccessful.
January 1951: Recapture of Seoul by Communist Forces
Communist forces recaptured Seoul in January 1951 after UN forces had initially taken control of it.
January 1951: Third Phase Offensive and Capture of Seoul
In January 1951, the PVA and KPA launched their Third Phase Offensive, utilizing night attacks and overwhelming UN forces, leading to the recapture of Seoul.
February 1951: Operations Thunderbolt and Killer
In February 1951, the Eighth Army launched Operations Thunderbolt and Killer to inflict maximum casualties on the KPA and PVA. Operation Killer resulted in the recapture of territory south of the Han River by the US I Corps and the capture of Hoengseong by the IX Corps.
April 1951: Fifth Phase Offensive and Heavy PVA Casualties
The PVA launched the Fifth Phase Offensive in April 1951, involving 700,000 troops. The offensive was met with fierce resistance by I Corps at the Imjin River and Kapyong, halting its advance. The PVA suffered heavy casualties, exceeding expectations and impacting their ability to sustain the offensive. The second impulse of the offensive targeting ROK and U.S. X Corps in the east also failed.
June 1951: MacArthur's Dismissal and Congressional Hearings
In June 1951, Congressional hearings investigated General MacArthur's defiance of President Truman's orders. The hearings confirmed MacArthur violated the US Constitution by exceeding his authority. MacArthur was relieved of command in April 1951 due to disagreements with Truman over war strategy and his public criticism of presidential decisions.
June 1951: UN Counteroffensive and Stalemate
In June 1951, the UN launched a counteroffensive after the Fifth Phase Offensive, pushing north of the 38th parallel. The PVA and KPA suffered significant losses, especially in the Chuncheon sector. The counteroffensive led to the beginning of a stalemate that persisted until the 1953 armistice.
July 1951: Armistice Negotiations Begin
In July 1951, armistice negotiations between the warring parties in the Korean War commenced.
July 1951: Armistice Negotiations Begin
In July 1951, armistice negotiations commenced in Kaesong, North Korea, marking the beginning of diplomatic efforts to end the Korean War. Despite the ongoing negotiations, fighting continued as both sides pursued their military objectives.
September 1951: PLAAF Entry and Logistical Challenges
In September 1951, the People's Liberation Army Air Force (PLAAF) began participating in the Korean War. The PVA faced severe logistical challenges, including shortages of food, ammunition, and transportation, impacting their combat effectiveness. Large-scale air defense training programs were conducted to mitigate the threat from UN air power.
October 1951: Operation Hudson Harbor
In October 1951, the US conducted Operation Hudson Harbor, simulating nuclear bombing runs over North Korea to assess their potential effectiveness.
November 1951: PVA Logistical Challenges
In November 1951, the PVA faced serious logistical problems, including inadequate equipment, overextended supply lines, and vulnerability to UN air attacks. A conference in Shenyang addressed these issues, resulting in efforts to improve infrastructure and logistics.
December 1951: Crackdown on Partisans
From December 1951 to March 1952, ROK security forces conducted operations against partisans and sympathizers.
1951: Limited UN Offensive and Chinese Active Defense
During the autumn of 1951, the UN launched a limited offensive to improve its defensive positions. Heavy fighting ensued at Bloody Ridge, the Punchbowl, and Heartbreak Ridge. The Chinese "active defense" proved effective, inflicting significant casualties on UN forces despite territorial losses.
1951: American Sabres Control Korean Skies
By 1951, despite being outnumbered, American F-86 Sabres effectively controlled the airspace over Korea, limiting communist air activity and enabling UN ground operations.
1951: Devastation of North Korea
By 1951, extensive bombing by the U.S. had left North Korea in ruins, forcing the relocation of factories, hospitals, schools, and government offices underground. General MacArthur expressed his dismay at the level of destruction during a Senate hearing, describing it as the worst he had witnessed in his military career.
January 1952: End of First Soviet Air Force Reporting Period
January 1952 marked the end of the first reporting period for Soviet air forces in Korea, showing a high initial kill ratio that later declined.
March 1952: Crackdown on Partisans
From December 1951 to March 1952, ROK security forces conducted operations against partisans and sympathizers.
1952: US Immigration Act of 1952
The U.S. Immigration Act of 1952 allowed for the naturalization of non-Black and non-White individuals as U.S. citizens, enabling military spouses and children from South Korea to enter the U.S.
1952: Artillery Exchanges and Communist Insurgency
Throughout 1952, intense artillery exchanges continued along the front lines in Korea. The UN forces maintained a significant firepower advantage. Meanwhile, the communist insurgency, backed by North Korea, saw a resurgence in South Korea.
1952: Turkey Joins NATO
Turkey joined NATO in 1952, partly influenced by its participation in the Korean War. This event also marked the beginning of diplomatic and trade relations between Turkey and South Korea.
July 1953: Signing of the Korean Armistice Agreement
The Korean Armistice Agreement was signed in July 1953, ending the fighting and establishing the Demilitarized Zone (DMZ).
July 1953: End of the Korean War
The Korean War ended in July 1953 with an armistice agreement, but no peace treaty, leading to a frozen conflict.
September 1953: Post-War Aid to North Korea
In September 1953, following the Korean War armistice, the Soviet Union and China provided substantial economic and industrial aid to North Korea, including debt cancellation, grants, and logistical support, to help rebuild the country's devastated infrastructure.
1953: Chinese Military Spending During the Korean War
By 1953, despite having an underdeveloped economy, China's military expenditure was the fourth highest globally for most of the war, following the US, USSR, and UK. However, with the end of the Korean War and the beginning of the First Indochina War, French military spending surpassed China's.
1953: Decline of Soviet Fighter Effectiveness
Throughout 1953, the effectiveness of Soviet fighters in Korea declined due to advancements in UN aircraft and tactics.
1953: Impact of Fifth Phase Offensive and Shift in Chinese Objectives
The failure of the Fifth Phase Offensive in 1951 marked a turning point in the Korean War. The heavy losses prompted Chinese leaders to shift their war aims from driving the UN forces out of Korea to seeking negotiations and defending Chinese security, ultimately leading to the stalemate and armistice negotiations.
1953: Mutual Defense Treaty Between South Korea and the United States
South Korea and the United States signed a Mutual Defense Treaty in 1953, following the Korean War.
1953: Eisenhower's Nuclear Caution
In 1953, President Eisenhower, like his predecessor, remained cautious about using nuclear weapons in Korea, fearing Soviet retaliation.
1954: Start of International Adoption of Korean Children
International adoption of Korean children commenced in 1954, largely due to the large number of mixed-race children, often referred to as "GI babies," fathered by U.S. and other UN soldiers, who faced social stigma in Korean society.
1965: US Immigration Act of 1965
The Immigration Act of 1965 significantly altered U.S. immigration policy towards non-Europeans, leading to a surge in Korean immigration, making them one of the fastest-growing Asian groups in the United States.
2003: South Korean Anti-American Sentiment
In 2003, a significant portion of South Koreans, around 46%, held unfavorable views of the United States.
2005: South Korean Truth and Reconciliation Commission
Between 2005 and 2010, a South Korean Truth and Reconciliation Commission investigated human rights violations, including atrocities committed during the Korean War and the Japanese colonial era. They excavated mass graves from the Bodo League massacres, further confirming details of these political executions.
2010: Commission's Findings on US Military Actions
In 2010, a reorganized South Korean Truth and Reconciliation Commission reported that most U.S. mass killings of South Korean civilians during the war resulted from "military necessity." However, they acknowledged a few instances of "low levels of unlawfulness" by the U.S. military but advised against pursuing reparations.
2010: Revised Chinese Casualty Figures
In 2010, the Chinese government revised its official count of casualties from the Korean War to 183,108 deaths, which included combat fatalities, and deaths from wounds and illness, and 21,374 POWs, and 25,621 missing.
2010: Findings of the Truth and Reconciliation Commission
In 2010, the South Korean Truth and Reconciliation Commission concluded that the majority of massacres investigated during the Korean War era were committed by South Korean forces (82%), with 18% committed by North Korean forces.
2011: Shift in South Korean Sentiment Towards US
By 2011, South Korean sentiment towards the U.S. had shifted dramatically, with a substantial increase in favorable views, reaching 74%.
2014: UN Inquiry into Human Rights Abuses in North Korea
In 2014, a UN inquiry concluded that the gravity, scale, and nature of human rights violations in North Korea are unparalleled in the contemporary world, a view shared by organizations like Amnesty International and Human Rights Watch.