When and How Did The Korean War Start?

Military historians estimate that the Korean War claimed about 2.5 million lives over a period of about three years. The carnage started when communist North Korea, backed by the People’s Republic of China (PRC) and the Soviet Union, overran the border with South Korea. The South was way below par; initially, they put up little to no resistance. This forced the United States to join the War and shore up support for the South Koreans. From then onward, the death toll mounted at a staggering rate. Cessation of hostilities eventually came in July 1953 with an armistice.

Synopsis of the Korean War

The Korean War started on June 25, 1950, when communist North Korea marched about 75,000 troops into the predominantly capitalist South Korea. The North’s army was called the North Korean People’s Army (KPA). The invasion by the North Korean army occurred during the early hours of Sunday. The North crossed the 38th parallel boundary that separated the two Koreas.

The North was backed by the Soviet Union and China while the South was supported by the United States and its allies (the United Nations). At its core, the Korean War was the product of the Cold War between the U.S. and the Soviet Union. The Americans fearing that North Korea would decimate the ill-equipped and ill-trained South Korean Army (ROKA), entered the war. The U.S. sent troops to the Korean Peninsula in July 1950.

At the start of the war, the communist North clearly outnumbered and outperformed their foes in the south. However, the two sides became evenly marched as time progressed. Vast stretches of areas were constantly moving between the South and North. Soon, the war stalemated and became a frozen war. Both sides went on to lose severely, and it was clear that there was not going to be an outright winner. Also, the two nuclear superpowers, the Soviet Union and the U.S., feared that without some sort of armistice the Korean War would certainly escalate into a global war or a third World War. As a result, the fighting ended on 27 July 1953 with an armistice. Under the Korean Armistice Agreement, a Korean Demilitarized Zone was created.

In sum, the Korean War claimed millions of lives. Millions of US Dollars’ worth of properties were damaged as well. The psychological trauma the war caused was not confined to just the Korean Peninsula, it was felt all across the world. The War also ushered in a full-blown Cold War between the U.S. and the Soviet Union which lasted for another 4 decades or so.

Today, the two Koreas are technically at war with each other because no peace treaty was signed in 1953. Tensions between them can only be described as cold and dire: a situation that epitomizes the truest definition of a frozen conflict.

Brief History of how Korea got split up into two

The genesis of the Korean War can be traced all the way back to the beginning of the 20^th century during Imperial Japanese rule. From 1894 to 1905, the Empire of Japan made significant gains on the Korean Peninsula by banishing the hold China and the Soviet Union had on Korea.

The first of such territorial gains happened during the First Sino-Japanese War (1894-1895). By 1905, the Japanese had gained complete control over all of Korea. It defeated the last remaining regional power, Imperial Russia, during the Russo-Japanese War in 1905. Korea became a protectorate of Imperial Japan.

There was a lot of internal and external resistance to Japan’s rule from 1919 to 1925. Resistance typically came from China as well as exiled Koreans living in China and abroad. The resistance was split into two main groups. There was the group led by the US-based Syngman Rhee. Rhee was the president of the Korean Provisional Government in exile. The second resistance group was led by communist Kim Il-sung. II-sung spent most of his early years in the Soviet Union. Militarily, he was trained by the Soviets; he even rose to the rank of a major in the Red Army (the Soviets Army). These two Korean groups waged a fierce battle against Japan and its dominance in the Pacific all throughout World War II. The western powers (Allies), as well as China, decided at a Cairo Conference in 1943 to free the entire Korea from the Imperial rule of Japan.

After Japan was completely vanquished by the Allies in World War II, the Soviets occupied the Northern part of Korea. The Soviet army, for a brief period of time, even set their eyes on Seoul. However, they were halted in their tracks as a result of the agreement between the U.S. and the Soviets on August 10, 1945. In the agreement, the Soviets were allowed to control the north of Korea. The U.S., backed by the United Nations, were put in charge of the South. The two main faces that featured prominently in the negotiations were US Colonels Dean Rusk and Charles H. Bonsteel III. The border that split the two Koreas into the Soviet-occupied and the US occupied area was called the 38th Parallel.

1945 to 1950: Conditions in the two Koreas before the War

After Japanese capitulation on August 15, 1945, the US General Order No. 1 was issued. A Military Governor, U.S. Lieutenant General John R. Hodge was chosen to steer the affairs in the south pending a smooth transition to a democratic election. Hodge was in charge of the United States Army Military Government in Korea (USAMGIK) from 1945 to 1948.

The U.S. worked tirelessly to flush out sympathizers of the communist North (People’s Republic of Korea (PRK)). Also, there was a brief imposition of martial law in the South. General Hodge, along with Sygnman Rhee, outlawed the PRK in the south. In a similar fashion, North Koreans did not accept southerners because of their nationalistic and capitalistic ideologies.

In December 1945, the Soviets and the Americans set up the Joint US-Soviet Union Commission. The Commission’s job was to ease the tensions that were brewing in the border regions between the two Koreas. They floated the idea of unifying the two Koreas again; however, nothing tangible came out that initiative. In 1947, the United Nations became the official administrator in the South.

The administration of U.S. President Harry S. Truman more than anyone else wanted to resolve the issue on the Korean Peninsula. He, under the auspices of the United Nations, proposed that a general election be held throughout Korea. However, the North Koreans backed out of the election. They suspected that it was going to be anything but free and fair. The general election went as planned on May 10, 1948. In the end, Syngman Rhee became the President of the South on July 20, 1948. Their Northern foes, in turn, organized a parliamentary election on August 25, 1948. The Marxist guerrilla Kim II-sung became the unopposed leader in the North.

On August 15, 1948, the South became the Republic of Korea (South Korea). Things began to settle in the South. There were not as many skirmishes in both the South and North. The two superpowers, the U.S. and the Soviet Union, continued to lend support to their respective Korean allies. After several negotiations, the Soviets left the Korean Peninsula in 1948. A year after the Soviets’ departure, the Americans did so as well (in 1949). However, neither the Americans nor the Soviets out rightly stopped supporting South Korea and North Korea respectively.

Strength of the two armies

Militarily, the North strongly reinforced its capability. As of 1948, there were about 100,000 troops under the command of Kim II-sung. As usual, the North got most of its military hardware from communist China (PRC) and the Soviet Union. Training, as well as military equipment in the form of aircraft, tanks, artillery, and tanks, were provided to II-sung’s troops that now totaled about 150,000 to 200, 000 soldiers. Additionally, North Korea had about 210 fighter planes; 280 tanks; 200 artillery pieces; 110 attack bombers; and 150 Yak fighter planes and 35 reconnaissance aircraft. Historical data shows that as at the time that the North eventually attacked, they were far stronger than the South Korean Army.

The South, however, made some steady progress, although not as well organized as North Korea. South Korea’s main sponsor, the U.S. was war-fatigued as a result of World War II. Budget cuts and the army’s excessive focus on the atomic bomb were some other factors that worsened this fatigue. Also, the U.S. had greater concerns about the activities that were taking place in Europe. Hence, the U.S. provided very minimal military support to South Koreans. As at 1950, the South had 98,000 soldiers of which only 65,000 were minimally combat ready. They had no tanks. However, they did have 10 AT6 advanced-trainer airplanes. Although the records show that the South had those number of troops in the military and police, their troops were ill-prepared and ill-equipped to engage in any meaningful combat. The South’s problem was also compounded by a lot of internal political divisions.

The few communists in the South opposed the idea of having a democratic and independent South Korea. Soon, it turned into guerrilla warfare. Periodically, the North gave a helping hand to the southern communists. Historians believe that the internal friction in the South was one of the reasons why the South Korean Army was ill-trained and ill-prepared for the full-blown War with its Northern neighbors in 1950. Nevertheless, one cannot discount the fact that the U.S. was anything but interested in providing heavy weapons and supplies to the South Korean Army (Republic of Korea Army-ROKA). Shortly before the North’s invasion (as at 1949), the U.S. had less than 500 troops stationed in the South.

The North prepares to invade the South

Considering the number of skirmishes that 1949 witnessed, it was only a matter of time before the two sides resorted to war. However, the first person to take such bold steps was Kim II-sung. In 1949, he went at great lengths to secure the backing of Joseph Stalin, the Soviet Union’s leader. Kim II-sung felt that an invasion was appropriate because he reasoned that most South Koreans supported intervention from the North. Stalin rejected Kim’s argument. The Soviet leader believed that the North was not on a good military footing to secure a win against Seoul.

Stalin dispatched several military equipment and training to the North all throughout 1949. The North’s Army, the Korean People’s Army (KPA), worked vigorously to attain superior levels of capabilities. In addition to their staggering number of troops, mainland China’s communist leader Chairman Mao Zedong sent about 70,000 soldiers to Kim II-sung. These troops were the same Korean troops that helped Mao gain victory during the Chinese Civil War.

With everything reasonably set in the North, Stalin gave his blessings to the North Koreans in April 1950. Prior to that, there was a huge border clash on August 4, 1949. The South claimed that North Korean troops attacked their troops along the 38^th Parallel.

Another very significant thing worth noting is that Stalin counted on the U.S. not intervening in the South. He theorized that since the U.S. did not intervene in the Chinese Civil War; and since the U.S. had withdrawn virtually all of its troops, then it was unlikely for them to send troops back to South Korea. Hence he was expecting very little resistance to Kim II-sung’s push southward.

The Day North Korea attacked South Korea

Historical accounts state that the North Korean forces began their march (in two groups) into the South in the early hours of June 25, 1950. The North claimed that the South first attacked them. The north under the guise of trying to apprehend the culprits ventured into the South.

The first group of North Korean troops of about 53,000 overran the 38^th Parallel from the Imjin River. The second group of about 54,000 was divided into two. The first unit marched through Ch’unch’ŏn and Inje to Hongch’ŏn. The second unit pushed on through the east coast road near Kangnŭng. The goal of the North was to take Seoul. They were poised to destroy the government of Rhee once and for all.

The North Korean Army needed only about three days to overran Seoul. Rhee was forced to evacuate several government officials on June 27, 1950. The North destroyed the Hangang Bridge on 28 June 1950. The attack killed over 100 people. The bridge that was very vital to the Southern forces was now gone. By the end of June, close to all of Seoul was firmly in the hands of the North. The troops had fallen from 95,000 to 22,000. There were a lot of casualties. A great number of the South Korean army had also deserted or at worse switched sides to the North.

Intervention from the United States

Taking cognizance of how the South put up very little resistance, the U.S. intervened in July 1950. $12 billion dollars was set aside by Congress for the war in Korea.  Most of the money went into beefing up it’s military support and training to the South Koreans. Why then did the U.S. wait that long a period before it intervened?

The exact reason why the U.S. intervened in the Korean War at the time that it intervened was because President Truman was either reluctant or unwilling to join the war. He had long known of the North’s build up across the border. Prior to the war starting, the then Secretary of State, Dean Acheson did not even involve the South Koreans in the strategic Asian Defense Perimeter. The commander of the United States’ Far East Command (FECOM), General Douglas MacArthur, once opined that his forces in Japan had more pressing issues that the turmoil that was building up in Korea.

President Truman focused more on Europe. Trying to curtail the Soviet’s influence in Europe was more important to him than what transpired in the Korean Peninsula. Truman also thought that the Soviets stoked the Korea War with the goal of using it as a diversion to take the U.S. attention from Europe.

A second reason has to do with the fact that the U.S. was also worried that intervening in Korea could spiral into a third world war.

On the other side of the aisle: those in favor of an intervention argued that should Korea fall, Japan would be the only power in East Asia capable of standing against communist Soviets and China.

By July 1950, it became apparently clear to President Truman’s administration that the U.S. had to enter the Korean War. Only a few years ago, China fell to communism. And now South Korea was about to go in that way. Truman thought that if the Soviets went on checked, then there was likely to be a domino effect all across the world. Truman could certainly not allow that to happen. He even compared the communist threat posed by the North to the one Adolf Hitler posed during World War II.

Countries that took part in the Korean War

The U.S. secured the backing of the UN Security Council. UN Security Council Resolution of 82 on June 25, 1950, strongly condemned the North’s attack on its southern neighbors. Unsurprisingly, the Soviets stayed away from those Council sessions. The Soviets argued that the Korean War was an entirely civil war which meant that the U.N. Security Council had no legitimacy to intervene.

Regardless of the Soviet’s disagreement, the other two permanent members on the council contributed resources for an intervention in Korea. France and the United Kingdom contributed about 1,200 and 14,200 troops respectively. Back then, the Taiwanese Republic of China had a permanent seat. The U.S. made sure to keep Taiwan out of the war lest it provoked mainland communist China (the People’s Republic of China).

Support also came from a host of other European countries such as Belgium, Sweden, Denmark, the Netherlands, Greece, and Norway. The United Nations received backing from other non-European countries such as Colombia, Turkey, Canada, South Africa, New Zealand, Australia, Ethiopia, India, the Philippines, and Thailand.

The combined troop numbers of the American-led coalition amounted to about 970,000. The North, however, had about 1,600,000 troops backing them.

South Korea and its American-led UN Coalition Fight Back

President Truman ordered that military resources be transferred to South Korea. General MacArthur was responsible for this mission. Most of the U.S. military equipment were transferred from U.S. bases in Japan to South Korea. Resources were also sent to protect the Republic of China (Taiwan) lest mainland China (PRC) decided to attack it. The Taiwanese did not fight in Korea because the U.S. did not want to draw mainland China into the war.

The U.S. started with only their Air Force and Navy. Putting ground troops was out of the discussion initially because they feared the Soviets doing so. It must be noted that the U.S. Congress never issued a declaration of war. Truman had to keep things on down because such moves again could send the wrong signals to the Soviets or the Chinese.

The absence of a Congressional declaration of war probably explains why the U.S. media did not pay much attention to the Korean War. Those who paid attention to the war agreed with Truman’s use of the military.

However, once the U.S. realized that the Soviets weren’t going to attack the U.S., President Truman later committed ground forces.

The ground forces were not so effective at the start of the fight. Within a two-month span, the U.S. suffered several casualties around the enclave of Osan. Reports of desertion were frequent among both the U.S. and South Korean troops. The U.S. coalition simple could not deal effectively with the North’s onslaught. Thousands of civilians in the South were caught in the crossfire as well.

Around August of 1950, the Truman administration showed proper leadership. This reflected in General MacArthur’s strategies. Astute military minds such as Lieutenant General Walton H. Walker and Major General Chung II-Kwon coordinated to stem the flow of the North’s troops. General Walker was in charge of a brilliant military corps known as the Eighth Army.

Seoul falls back into the hands of the South

The efforts of the United Nations Command began to bear fruits around the later part of the 1950 autumn. Military supplies arrived on time. The coalition also took possession of tanks, antiaircraft guns, and rocket launchers.

The Fifth Air Force of the U.S. took center stage with their P-51 Mustangs, F-80 B-26, and B-29 and F-28. This motivated the troops of the Republic of South Korea Army (ROKA). Their numbers also increased.

The People’s Republic of Korea (KPA) army of the North started experiencing a period of surrenders, defections, and desertions.

From August 18 to 26, the South enjoyed significant victories over the KPA during the Battle of Tabu-dong. By September 12, 1950, the KPA withered to about 60,000 soldiers. Their command chain was in disarray.

After intense fighting in September 1950 during the Inch’on Battle, the U.S. led coalition along with South Korean forces pushed all the North’s forces out of the South. South Korea was back in the hands of the South.

The KPA returned to the North having suffered about 50,000 casualties. 13,000 of their soldiers were either captured or missing in action. As the KPA retreated, they took a lot of prisoners along. Some were even held hostage and used as slave laborers. The not so lucky ones were brutally executed. In Taejon alone, about 5,000 civilians were executed.

The South was not devoid of such war crimes neither. Equally, brutal crimes were committed under the auspices of Rhee. His goal was to flush out elements of the North as well as communist sympathizers. They brutalized anyone suspected of supporting the communist North. Additionally, the U.S. was reckless in its attack to take South Korea back.

The UN Command Pushes into North Korea

The U.S. Army had the winds in their sails. On September 27, 1950, the U.S. leadership allowed General MacArthur to go beyond the 38^th Parallel and into the North. The United Nation’s Command (UNC) sought to capture all of North Korea. Destroy the KPA and then unite the two Koreas under the umbrella of democracy.

In October, both ROKA and the U.S. forces pushed into the North. By October 19, Pyongyang was under their control. This was a very interesting turn of fortunes. Only a few months ago, Kim Il-sung’s North Korean forces were in Seoul.

The KPA weary and bit dazed retreated to Kanggye. They waited patiently for whatever support the Soviets or the Chinese could offer. Mao Zedong of China came to their aid. However, he had to secure air support from the Soviets. Stalin in turn guaranteed air protection for the Chinese troops. He provided additional military equipment to the North as well.

The Introduction of Chinese troops

Under the command of General Peng Dehuai, The Chinese People’s Volunteers Force (CPVF) joined the war. The Chinese resorted to novel strategies like attacking in the night; they destroyed supply routes and ambushed and carried out several improvised counter attacks.

Some weeks into CPVF joining the war, the ROKA had lost about 6000 soldiers and the coalition lost about 2000 men.

Also, there was a lot of fighting in the air between the U.S. and the Soviets. This air battle lasted about two and a half years.

By December 14, 1950, China had successfully pushed the South Koreans out of the North. In another twist of the war, the CPVF pushed ROKA and the U.S. troops all the way into Seoul. From December 31 of 1950 to January 5, 1951, the CPVF recaptured Seoul.

With the passage of time, the Korean War was stalemating. It had turned into one where vast areas both in the North and the South changed hands on a continuous basis. For example, Seoul, on March 14, 1951, changed hands for the fourth time in just less than 9 months. This time around, Seoul fell under the control of the UN forces.

Ridgway replaces MacArthur

There was not going to be an outright winner. This standoff infuriated some U.S. military commanders on the ground. One such commander was General MacArthur. He felt that the Truman Administration was not doing enough to secure the South a decisive victory in the war. For this and many more other ‘insubordination’ acts, MacArthur got replaced by Lieutenant General Matthew Ridgway on April 11, 1951.

April 25, 1951, saw the Battles of Kapyong and the Imjin River. The Chinese forces were far greater than General Ridgway’s forces. The U.S. forces fought gallantly and held kept their lines around Seoul. These two battles were horrid and absolutely damaging to both the North and the South.

The War stalemates

When it had become apparently clear that both sides were a bit evenly matched, the Korean War stalemated. The U.S. and the Soviet made sure that they did nothing irrational to escalate it further.

This stalemate, which started around July 8, 1951, continued until there was an armistice on July 27, 1953. With the exclusion of the Rhee, almost every military leader involved in the war had come to realize that unification was out of the question.

There were fewer ground troops movement although the aerial battle ensued between the U.S. and the Soviet Union. Skirmishes mainly occurred around the 38th parallel.

Talks begin at Kaesong

The U.S. and the Soviet Union were more than anxious to bring to an end, the war. In July 1951, the North Koreans and the Chinese picked Kaesong for preliminary negotiations, to begin with, the South. On several occasions, negotiators failed at securing an agreement. The most contentious issue was the prisoners each side had. Irrespective of this impasse in their negotiations, the two Koreas continued to battle each other. The casualties and carnage just kept piling up on both sides.

Korean War Prisoners

The two warring sides, after months of negotiations, came to an agreement to use the Geneva Convention of 1949 to deal with the prisoners of war (POW). The Convention states that holding countries are obliged to return the POW to their homelands after the war is over. It also states that the POWs are not to be tortured or abused in any manner.

Guess what both sides did to their respective POW? They resorted to murdering some of the POW; torture; starvation; and abuse. This was evident in the sharp disparity between ‘the missing in action’ (MIA) lists and the lists of prisoners that came from both sides. For example, the South handed in a list that contained 11,500 missing in Action. However, the North claimed that it had only about 3,000 POW. The South had about 7000 POW out of about 88, 000 MIA list.

Truman allowed the POW who did not want to return stay in the South. After months of negotiations, China accepted the voluntary repatriation

The Korean War Armistice Agreement

Eisenhower election and the death of Stalin helped draw the curtains on the war. Also, the public was getting tired of the endless talks and casualties. The stalemate was frustrating. In the Soviet Union, Stalin’s successors did not want to continue the war. Without the help of the Soviets, Mao Zedong was forced to halt as well.

Rhee was not in favor of completely ending the war. He still habored desires to march to the North and then unify the two Koreas. However, he eventually accepted the cessation of hostilities in exchange for a rock-solid security agreement with the U.S. as well as a one billion dollar financial aid. Rhee accepted the armistice on July 9, 1953.

On the day of signing, Mark W. Clark (from the UNC), Peng Dehuai (from the Chinese) and Kim Il-sung (representing the North Koreans) signed the armistice. The agreement helped the two Koreas create a demilitarized zone (also known as the DMZ) approximately along the 38th Parallel that had existed before the war.

To this day, the two Koreas are still miles away from signing a peace treaty. What this means is that the two countries are technically still at war with each other: a frozen war that sees a few skirmishes every once in a while along the DMZ.

Frequently asked questions

The following key questions and answers provide a brief summary about the Korean War.

What caused the war?

The primary cause was the division of Korea at the 38th parallel after World War II, with the North under Soviet influence and the South under American influence. Tensions between the two zones escalated into open conflict when North Korean troops invaded South Korea in 1950.

Who were the major participants in the war?

The main participants were North Korea, backed by China and the Soviet Union, and South Korea, supported primarily by the United States and other Western United Nations members.

Was there a clear winner in the Korean War?

The war ended in a stalemate with the Korean Armistice Agreement in 1953. Neither side achieved a complete military victory, and the Korean Peninsula remains divided to this day.

Where was the frontline by the end of the war?

By the end of the war, the frontline stabilized near the 38th parallel, which became the Demilitarized Zone (DMZ). This heavily fortified border still separates North and South Korea.

Why did China intervene in the Korean War?

China intervened primarily to prevent a unified Korea under U.S. influence on its border. They were concerned about a potential threat if U.S. troops were stationed close to Chinese territory.

How many people died in the Korean War?

Several millions of people lost their lives as a result of this war. This number includes both military personnel and civilians from both North and South Korea, China, and UN forces, with the majority being Koreans.

Is the Korean War technically over?

While active hostilities ceased in 1953, the war has not officially ended. The Korean Armistice Agreement was a ceasefire, not a peace treaty. Hence, the two Koreas are technically still at war.

Why is this war sometimes called “The Forgotten War”?

It’s often overshadowed by World War II, which ended just five years earlier, and the Vietnam War, which began a decade later. Due to its inconclusive ending and the lack of extensive media coverage, it has sometimes been overlooked in American history.

What were the long-term consequences of the war?

The war solidified the division of the Korean Peninsula, which persists to this day. It also marked the beginning of large-scale U.S. military involvement in Asia during the Cold War era, influencing U.S. foreign policy in the region for decades.