Third Battle of Seoul

The Third Battle of Seoul, also known as the Chinese New Year's Offensive, the January–Fourth Retreat (1·4 후퇴) or the Third Phase Campaign Western Sector, was a battle of the Korean War, which took place from December 31, 1950 to January 7, 1951 around the South Korean capital of Seoul. In the aftermath of the major Chinese victory at the Battle of the Ch'ongch'on River, the United Nations Command started to contemplate on the possibility of evacuation from the Korean Peninsula. Upon learning this development, China's Chairman Mao Zedong ordered the Chinese People's Volunteer Army to cross the 38th parallel in an effort to pressure the United Nations forces to withdraw from South Korea.

On the New Year Eve of 1951, the Chinese 13th Army attacked the Republic of Korea (ROK) 1st, 2nd, 5th and 6th Infantry Divisions along the 38th parallel, breaching United Nations Forces' defenses at the Imjin River, Hantan River, Gapyeong and Chuncheon in the process. To prevent the Chinese forces from overwhelming the defenders, the United States Eighth Army under the command of Lieutenant General Matthew B. Ridgway evacuated Seoul on January 3, 1951.

Although Chinese forces captured Seoul by the end of the battle, the Chinese invasion of South Korea galvanized the United Nations' support for South Korea, while the idea of evacuation was soon abandoned by the United Nations Command. At the same time, the Chinese People's Volunteer Army were exhausted after months of nonstop fighting since the start of the Chinese intervention, thereby allowing the United Nations forces to regain the initiative in Korea.

Background
With the People's Republic of China entering the Korean War during the winter of 1950, the conflict had entered a new phase. To prevent North Korea from falling under United Nations (UN) control after the UN landing at Incheon, the Chinese People's Volunteer Army (PVA) entered Korea and launched a series of surprise attacks against the UN forces near the Sino-Korean border at the end of 1950. The resulting battles at the Ch'ongch'on River Valley and the Chosin Reservoir forced the UN forces to retreat back to the 38th parallel by December 1950, with Chinese and North Korean forces recapturing much of North Korea. On the Korean western front, after the United States Eighth Army suffered a disastrous defeat at the Ch'ongch'on River, the Eighth Army retreated back to the Imjin River while setting up defensive positions around the South Korean capital of Seoul. Although the US Eighth Army was ordered to hold Seoul for as long as possible, General Douglas MacArthur planned a series of withdrawals to the Pusan Perimeter under the assumption that UN forces were about to be overwhelmed in Korea. General Walton Walker, commander of the US Eighth Army, was killed in a traffic accident on December 23, and Lieutenant General Matthew B. Ridgway assumed command of the Eighth Army on December 26, 1950. At the UN, a ceasefire along the 38th parallel was proposed to China on December 11, 1950 in order to avoid any further escalation of hostility between China and US.

Although the PVA had been weakened from their earlier battles, with nearly 40 percent of its forces rendered combat ineffective, its unexpected victories over the UN forces had convinced the Chinese leadership of the invincibility of PVA. Immediately after the PVA 13th Army's victory over the US Eighth Army at the Ch'ongch'on River, China's Chairman Mao Zedong started to contemplate another offensive against the UN forces on the urging of North Korean Premier Kim Il-sung. After learning of MacArthur's plans and the UN ceasefire, Mao also believed that the UN evacuation of the Korean Peninsula was imminent. Although the over-stretched Chinese logistics prevented the PVA from launching a full scale invasion against South Korea, Mao still ordered the PVA 13th Army to launch an intrusion, dubbed the "Third Phase Campaign", to hasten the UN withdrawal and to demonstrate China's desire for a total victory in Korea. On December 23, 1950, China's Foreign Minister Zhou Enlai formally rejected the UN ceasefire while demanding all UN forces to be withdrawn from the Korean Peninsula.

Locations, terrain and weather
Seoul is the capital city of South Korea, which is roughly bisected into northern and southern halves by the Han River. Seoul is also located at 35 mi south of the 38th parallel. The battle was fought over the UN defenses at the 38th parallel, which stretches horizontally from the Imjin River mouth on the Korean west coast to the town of Chuncheon in central Korea. A road dubbed "Route 33" runs south across the 38th parallel at the Hantan River, passes through Uijeongbu and eventually arrives at Seoul, and it is an ancient invasion route towards Seoul. Another road ran across the Imjin River, and it connects Seoul and Kaesong through the town of Munsan and Koyang. Finally, a road runs through Chuncheon and it connects to Seoul from the northeast. The harsh Korean winter, with temperatures as low as -20 °C, had frozen the Imjin and the Hantan River over most of the river crossings, and it eliminated a major obstacle for the attacking Chinese forces.

Forces and strategies
By December 22, 1950, the US Eighth Army's front had stabilized along the 38th parallel. Just days before his death, Walker placed the US I Corps, the US IX Corps, and the ROK III Corps of the Eighth Army along the 38th parallel to defend Seoul. The US I and IX Corps were to defend the Imjin and Hantan River respectively, while the ROK III Corps were to guard the areas around Chuncheon. The boundary between US I and IX Corps was marked by Route 33, and was defended by the ROK 1st Infantry Division on the west side and the ROK 6th Infantry Division on the east side.

Because the South Korean forces had suffered nearly 45,000 casualties at the end of 1950, most of the South Korean units were composed of raw recruits with little combat training. After inspecting the front just days before the battle, General J. Lawton Collins, the US Army Chief of Staff, concluded that most of the ROK formations were only fit for outpost duties. At the same time, the US Eighth Army was also suffering from low morale due to its earlier defeats, and most of its soldiers were anticipating an evacuation from Korea. The Eighth Army's lack of will to fight and to maintain contact with Chinese forces resulted in a lack of information on Chinese troop movements and intentions. After inspecting the front on December 27, Ridgway ordered the US I and IX Corps to organize a new defensive line around Koyang to Uijeongbu, called the Seoul Bridgehead line, to cover the Han River crossings in case the UN forces were forced to evacuate Seoul.

The Chinese forces, however, were also suffering from logistics problems and exhaustion from their earlier victories. Arguing against the Third Phase Campaign on December 7, PVA Commander Peng Dehuai telegraphed to Mao that the PVA would need at least three months to replace its casualties, while most of its troops were in critical need of resupply, rest and reorganization. The Chinese logistics system, which was based on the concept of People's War with the native population supplying the army, also ran into difficulties due to the indifferent, and sometimes hostile, Korean population near the 38th parallel. The Chinese were now suffering from hunger and the lack of winter clothing.

Responding to Peng's concern over the troops' conditions, Mao limited the scope of the Third Phase Campaign to pin down the South Korean forces along the 38th parallel while inflicting as much damage as possible. Upon noticing that the US units were not interspersed between the South Korean formations, therefore unable to support the South Koreans, Mao ordered the PVA 13th Army to destroy the ROK 1st Infantry Division, the ROK 6th Infantry Division and the ROK III Corps. Following Mao's instruction, Peng placed the PVA 38th, 39th, 40th and 50th Corps of the 13th Army in front of the ROK 1st and 6th Infantry Division, while the 42nd and the 66th Corps of the 13th Army were moved into ROK III Corps' sector. The start date of the offensive was set to the New Year's Eve in order to take advantage of the night assault under a full moon and the low alertness of the UN soldiers during the holiday. For the same reasons Ridgway had predicted that the New Year Eve would be the likely time for the new Chinese offensive. Believing that the destruction of the South Korean forces at the 38th parallel would render the UN forces incapable of counterattacks in the future, Mao promised to pull all Chinese troops off the front line for rest and refit by the end of the campaign.

Battle
On the evening of December 31, 1950, the PVA 13th Army launched a massive attack against South Korean forces along the 38th parallel. Along the Imjin River and the Hantan River, the PVA 38th, 39th, 40th and 50th Corps managed to decimate the ROK 1st Division while routing the ROK 6th Division. At the Chuncheon sector, the PVA 42nd and the 66th Corps forced the ROK III Corps into full retreat. With the defenses at the 38th parallel completely collapsed by January 1, 1951, Ridgway ordered the evacuation of Seoul on January 3.

Actions at the Imjin River and the Hantan River


By December 15, 1950, the ROK 1st Infantry Division had retreated back to the town of Choksong on the southern bank of the Imjin River—its original defensive position at the start of the Korean War. On the right flank of the ROK 1st Infantry Division, the ROK 6th Infantry Division was located at the north of Dongducheon along the southern bank of the Hantan River. The ROK 1st Infantry Division planned to defend the Imjin River by placing its 11th and 12th Regiments at the west and the east side of Choksong respectively, while the ROK 6th Infantry Division defended the Route 33 at the Hantan River by placing its 7th and 19th Regiments on each side of the road. Both the ROK 15th Regiment of the 1st Infantry Division and the ROK 2nd Regiment of the 6th Infantry Division were placed in the rear as reserves. The South Koreans had also constructed numerous bunkers, barbed wire obstacles and minefields on both banks of the river in order to strengthen defenses and to maintain troop morale.

Faced with the South Korean defense, the Chinese had prepared for well over a month for the offensive. In the weeks before the operational orders for the Third Phase Campaign were issued by PVA High Command, the advance elements of the PVA 39th Corps had been conducting detailed reconnaissance on South Korean defenses. The South Korean positions were then thoroughly analyzed by Chinese commanders, engineers and artillery officers. Chinese "thrust" companies, which were composed of specially trained assault and engineer teams, were also organized to lead the attack across the Imjin and Hantan River. During the preparation, the Chinese artillery units had suffered heavy losses under UN air attacks, but PVA Deputy Commander Han Xianchu still managed to bring up 100 artillery pieces against the South Korean fortifications. On December 22, the PVA High Command issued the operational orders that signaled the start of the Third Phase Campaign. The PVA 39th and 50th Corps were tasked with the destruction of the ROK 1st Infantry Division, while the 38th and the 40th Corps were tasked with the destruction of the ROK 6th Infantry Division.

Acting on Ridgway's prediction, the ROK Army Headquarters ordered all units to full alert at the dusk of December 31, but many of its soldiers were either drunk from the New Year celebration or had abandoned their posts in order to escape the cold. The Chinese artillery units began to bomb the South Korean defenses at 16:30 on December 31. The first blow fell on the ROK 12th Regiment of the 1st Infantry Division, due to the fact that it acted as both the boundary between the ROK 1st and 6th Infantry Divisions and the boundary between US I and IX Corps. Because the river banks on ROK 12th Regiment's flanks were composed of high cliffs difficult for the attackers to scale, most of the regiment's strength were used to defend its center. Upon noticing this development, the PVA 39th Corps decided to use ROK 12th Regiment's flanks as the main points of attack in order to achieve maximum surprise. Following a feint attack on the ROK 12th Regiment's center, the PVA 116th and the 117th Divisions of the 38th Corps struck both flanks of the ROK 12th Regiment. The ROK 12th Regiment was caught off guard and offered little resistance, and within hours the regiment was cut to pieces with a battery of the US 9th Field Artillery Battalion seized by the Chinese. Under the cover of the fleeing Korean soldiers, the attacking Chinese forces then penetrated the ROK 15th Regiment's defense without firing a shot. Desperate to contain the Chinese breakthrough, Brigadier General Paik Sun Yup of the ROK 1st Infantry Division used the division's rear service personnel to form an assault battalion, but the battalion was unable to stop the Chinese advance. With only the ROK 11th Regiment remaining intact by the morning of January 1, the ROK 1st Infantry Division was forced to withdraw on January 2.

The Chinese attacks against the ROK 6th Infantry Division, however, did not go as commanders had planned. The original plan called for the PVA 38th and the 40th Corps to attack the ROK 19th Regiment on the 6th Infantry Division's right flank, but the bulk of the Chinese forces mistakenly attacked the US 19th Infantry Regiment of the US 24th Infantry Division, which was stationed to the east of the ROK 19th Regiment. The poor intelligence had also made the Chinese charge through several minefields, resulting in heavy casualties to the attackers. In spite of the losses, the Chinese pushed the US 19th Infantry Regiment back, exposing the right flank of the ROK 6th Infantry Division in the process. With the ROK 1st Infantry Division out of action and the US 24th Infantry Division's defenses penetrated, the Chinese forces on both flanks of the ROK 6th Infantry Division then advanced southward in an attempt to encircle the division. By midnight of the New Year's Eve, the ROK 6th Infantry Division was forced into full retreat. Although the Chinese managed to intercept some elements of the ROK 6th Infantry Division, most of the South Koreans escaped the trap by infiltrating the Chinese lines using the mountain trails. As Ridgway tried to inspect the front on the morning of January 1, he was greeted by the fleeing and weaponless remnants of the ROK 6th Infantry Division a few miles north of Seoul. Despite Ridgway's efforts to stop the retreat, the division continued to flee south. It was not until the personal intervention of South Korean President Syngman Rhee that the division finally stopped its retreat. By the night of January 1, the UN defenses at the Imjin River and the Hantan River had completely collapsed with the Chinese advancing 9 mi into UN territory. The Chinese stopped their advance on January 2.

Actions at Gapyeong and Chuncheon
At the beginning of the battle the ROK III Corps was located to the east of the US 24th Infantry Division of the US IX Corps, defending the 38th parallel to the north of Gapyeong (Kapyong) and Chuncheon. Composed of four divisions, the ROK III Corps placed its ROK 2nd Infantry Division on the corps' left flank at the hills north of Gapyeong, while the ROK 5th Infantry Division defended the corps' center at Chuncheon. The cold winter created great difficulties for the South Korean defenders, with the heavy snow hindering construction and icy roads limiting food and ammunition supplies. North Korean guerrillas were also active in the region, and had caused serious disruption in the rear of the ROK III Corps.

The Chinese operational order for the Third Phase Campaign called for the 42nd and the 66th Corps to protect the Chinese left flank by eliminating the ROK 2nd and 5th Infantry Divisions, while cutting the road between Chuncheon and Seoul. Following instructions, the two Chinese corps quickly struck after midnight on New Year's Eve. The PVA 124th Division first penetrated the flanks of the ROK 2nd Infantry Division, then blocked the division's retreat route. The trapped ROK 17th and 32nd Regiments of the ROK 2nd Infantry Division were forced to retreat in disarray. With the PVA 66th Corps pressuring the ROK 5th Infantry Division's front, the PVA 124th Division then advanced eastward in the Korean rear and blocked the ROK 5th Infantry Division's retreat route as well. The maneuver soon left the ROK 36th Regiment of the ROK 5th Infantry Division surrounded by Chinese, and the ROK 36th Regiment had to escape by infiltrating the Chinese lines using mountain trails. By January 1, the ROK III Corps had lost contact with the 2nd and 5th Infantry Divisions, while the rest of the III Corps were retreating to the town of Wonju. On January 5, the PVA 42nd and 66th Corps were relieved by the North Korean People's Army (KPA) II and V Corps, and the North Koreans launched a separate offensive towards Wonju.

Evacuation of Seoul


In the aftermath of the Chinese attacks on along the 38th parallel, Ridgway worried that the Chinese would exploit the breakthrough at Chuncheonen to circle the entire Eighth Army. He also lacked confidence in the UN troops' ability to hold against the Chinese offensive. On the morning of January 3, after conferring with Major General Frank W. Milburn and Major General John B. Coulter, commanders of the US I and IX Corps, respectively, Ridgway ordered the evacuation of Seoul. With the collapse of the UN defenses at the 38th parallel, the retreat had already started on January 1. At 09:00 on January 1, Milburn ordered US I Corps to retreat to the Seoul Bridgehead line. Following his orders, the US 25th Infantry Division of I Corps took up position to the west of Koyang, while the British 29th Independent Infantry Brigade of I Corps had dug in to the east. To the east of I Corps, Coulter also ordered the withdrawal of the US IX Corps at 14:00 with the Anglo-Australian 27th British Commonwealth Brigade covering the rear. Some Chinese forces managed to trap the 3rd Battalion, Royal Australian Regiment (3RAR) of the 27th British Commonwealth Brigade at Uijeongbu during their attacks against the ROK 6th Infantry Division, but the battalion escaped the trap with four wounded. By midnight on January 1, the US 24th Infantry Division of the IX Corps reached the Seoul Bridgehead line at the south of Uijeongbu, and the 27th Commonwealth Brigade was moved into the IX Corps rear as reserves.

The Chinese forces lacked the ability to lay siege to the city, so the evacuation order caught Peng by surprise. On the morning of January 3, Peng ordered the PVA 13th Army to pursue the retreating UN forces by attacking towards Seoul. The US 24th, 25th Infantry Division and the British 29th Infantry Brigade soon bore the brunt of the Chinese attacks. In US IX Corps' sector, PVA 38th Corps immediately attacked the US 24th Infantry Division as the American were trying to withdraw. In the fierce fighting that followed, the US 19th Infantry Regiment on the division's left flank was involved in numerous hand to hand struggles with the Chinese around Uijeongbu. The Chinese overran the E and G company of US 19th Infantry Regiment during their attacks, but American artillery and air strikes soon inflicted 700 casualties in return. Faced with the heavy Chinese pressure, the 27th Commonwealth Brigade was again called in to cover the retreat of US IX Corps. After the US 24th Division evacuated Seoul on the night of January 3, the 27th Commonwealth Brigade started to cross the Han River on the morning of January 4, and by 07:40 the entire US IX Corps had left Seoul.

On the left flank of the US 24th Infantry Division, the British 29th Infantry Brigade of the US I Corps was involved in the hardest fighting of the entire battle. In the 29th Infantry Brigade's first action of the Korean War, the brigade was ordered to defend the areas east of Koyang on the Seoul Bridgehead line. The 1st Battalion, Royal Ulster Rifles (1RUR) covered the brigade's left flank, while the 1st Battalion, Royal Northumberland Fusiliers (1RNF) was stationed on the brigade's right flank. The 1st Battalion, Gloucestershire Regiment and the 21st Thai Battalion covered the brigade's rear with artillery support. At 04:00 on January 3, 1RUR first made contact with the 149th Division of the PVA 50th Corps. The Chinese surprised and overran the B and D company of 1RUR, but a counterattack by Major C. A. H. B. Blake of 1RUR restored the battalion's position by the morning. While 1RUR was under attack, the Chinese forces also infiltrated 1RNF's positions by exploiting the unguarded valleys between hilltops occupied by the British. The entire 1RNF soon came under sniper fire and the Chinese made repeated attempts to capture the Y Company of 1RNF. To restore 1RNF's position, Brigadier Thomas Brodie of the 29th Infantry Brigade sent the W Company of 1RNF with four Churchill tanks as reinforcement. The reinforcement was met with machine gun and mortar fire, but the Chinese resistance immediately crumbled under the Churchill tanks' devastating assaults. The surviving Chinese troops fled under the bombardment from 4.2 inch mortars and 25 pounder field guns. In the aftermath of fighting, the 29th Infantry Brigade suffered at least 16 dead, 45 wounded and 3 missing, while 200 Chinese dead were found within 1RNF's position.



While the British 29th Infantry Brigade and the PVA 149th Division fought at the east of Koyang, the US 25th Infantry Division of the US I Corps started to withdraw on the left flank of 29th Infantry Brigade. The evacuation plan called for a coordinated withdrawal between the US 25th Infantry Division and the British 29th Infantry Brigade in order to prevent the Chinese from infiltrating the UN rear areas, but the heavy fighting soon made the coordination between American and British units impossible. After the US 27th Infantry Regiment of the 25th Infantry Division formed the rear guard of the US I Corps, the 25th Infantry Division and the 29th Infantry Brigade were ordered to evacuate at 15:00 on January 3. The 25th Infantry Division retreated with little difficulties, but the withdrawal of the 29th Infantry Brigade did not start until after dark at 21:30. With the road completely open between the American rear guards and the British units, the 446th Regiment of the PVA 149th Division infiltrated UN rear areas and set up an ambush against 1RUR and the Cooper Force of the 8th King's Royal Irish Hussars. 1RUR and the Cooper Force were then quickly overran by Chinese soldiers, most of whom were completely unarmed. The Chinese had also attacked the Cromwell tanks of the Cooper Force with bundle grenades and Bangalore torpedoes, setting several on fire. In the desperate hand on hand fighting that followed, although 100 soldiers from 1RUR managed to escape the trap under the command of Major J.K.H. Shaw, Major Blake of 1RUR and Captain D. Astley-Cooper of the Cooper Force were killed in action, while another 208 British soldiers were missing in action, most of whom were captured by the Chinese. The US 27th Infantry Regiment tried to rescue the trapped British troops, but Bordie stopped the rescue in order to prevent more unnecessary losses.

When the British 29th Infantry Brigade left Seoul at 08:00 on January 4, the US 27th Infantry Regiment became the last UN tactical unit that remained in the city. After fighting several more holding engagements at the outskirt of Seoul, the 27th Infantry Regiment crossed the Han River at 14:00 on January 4. On January 5 Ridgway ordered the Eighth Army to withdraw from the Han River and to form a new defensive line, dubbed "Line D", at the 37th parallel between Pyeongtaek and Changhown. The Incheon port and the Kimpo Airfield were then demolished to deny their use to the Chinese and North Korean forces.

On the afternoon of January 4, the KPA I Corps, the PVA 38th Corps and the PVA 50th Corps entered Seoul, but they were only greeted by an empty city in flames. Most of the civilians had either fled south through the frozen Han River or evacuated to the nearby countryside. The South Korean government in Seoul, which was reduced to essential personnel before the battle, also left the city with little difficulties. A Chinese platoon reached the Seoul City Hall at about 13:00 and raised the North Korean flag. On January 5, Peng ordered the PVA 50th Corps and the KPA I Corps to seize Gimpo and Incheon while instructing all other units to rest on the northern bank of the Han River. By January 7, Peng halted the Third Phase Campaign due to troop exhaustion and to prevent a repeat of the Incheon landing.

Aftermath
Although the UN casualties were moderate during the battle, the Third Battle of Seoul was a significant success for the Chinese military in Korea, and the UN forces' morale had sunk to its lowest point during the war. Ridgway was also extremely displeased with the performance of Eighth Army, which he had no control over due to the sudden death of Walker. Ridgway then took immediate steps to restore the morale and fighting spirit of the UN forces in Korea. With Ridgway leading the Eighth Army, MacArthur started to regain confidence in UN forces' ability to hold Korea, and the UN evacuation plan was abandoned on January 17.

Meanwhile at the UN, although the UN members and US were initially divided on how to respond to Chinese intervention in Korea, the Chinese rejection of UN ceasefire soon rallied the UN members towards US. Immediately afterward, a UN resolution that condemned China as an aggressor was passed on February 1. In the opinion of historian Bevin Alexander, the Chinese rejection of UN ceasefire had damaged the international prestige it had built from its earlier military successes, and this later made it difficult for China to either join the UN or to deny US support for Taiwan. The Korean War, which ultimately ended at the 38th parallel, would drag on for another two bloody years due to the Chinese demand for all UN forces to be withdrawn from the Korean Peninsula.

Despite its victory, the PVA had become completely exhausted after fighting nonstop since the start of the Chinese intervention. PVA Deputy Commander Han Xianchu later reported to Peng that although combat casualties had been light with only 8,500 battle casualties, the poor logistics and the exhaustion had cost the "backbone" of the Chinese forces during the Third Phase Campaign. US Far East Air Forces' "Interdiction Campaign No.4 ", which was launched on December 15, 1950 against Chinese and North Korean supply lines, also made the Chinese unable to sustain any further offensives southward. Believing that the UN forces in Korea were thoroughly demoralized and unable to counterattack, Mao finally permitted the PVA to rest for at least two to three months, while Peng and other Chinese commanders were planning for one last decisive battle in the spring of 1951. But to the surprise of Chinese commanders, Ridgway and the Eighth Army soon counterattacked the PVA with Operation Thunderbolt on January 25, 1951.