The First Battle of Seoul was one of the early battles of the Korean War. Following the border engagements at the outbreak of the war, it was fought between the Republic of Korea Armed Forces and the Korean People's Army of North Korea from 26 to 28 June 1950 across the central region of South Korea, centering on the city of Seoul.
The battle resulted in the capture of Seoul by the Korean People's Army, while South Korean forces were forced to retreat south of the Han River.
Background
At 3:30 a.m. on 25 June 1950, the Korean War began when the Korean People's Army crossed the 38th Parallel, launching a Blitzkrieg offensive spearheaded by T-34 tanks and supported by artillery fire. During the planning of Operation Pokpung ("Storm"), the North Korean leadership calculated that the fall of Seoul would effectively determine the outcome of the war and bring the conflict to a swift conclusion. With this objective in mind, the Korean People's Army divided its forces into two corps. The 1st Corps served as the main attacking force and launched a full-scale offensive toward Seoul, while the 2nd Corps conducted supporting operations to protect the advance of the 1st Corps. The Republic of Korea had not anticipated a large-scale offensive, and only some units had independently adopted heightened defensive measures. As a result, the Korean People's Army was able to achieve a near-complete surprise attack.
The South Korean military was inferior to the Korean People's Army in nearly every respect, including manpower, equipment, and training. In particular, the Republic of Korea Army possessed few effective anti-tank weapons, and the superiority of North Korean armored forces created widespread fear among South Korean troops, contributing to their withdrawal. Nevertheless, South Korean forces maintained high morale, and in some cases succeeded in destroying North Korean tanks through close-quarters assaults. In addition, many of the frontline defensive units conducted effective defensive operations by making skillful use of river and other natural terrain features as obstacles. As a result, except in the Uijeongbu sector, where no significant natural obstacles existed, South Korean defensive lines did not completely collapse. However, in the Uijeongbu, the Korean People's Army's offensive, supported by the shock effect of its armored units, placed the city of Uijeongbu in an increasingly precarious situation.
Aftermath
Munsan–Bongilcheon sector
The 1st Infantry Division (South Korea) of the Republic of Korea Army, which was defending the area around Munsan, had lost the railway bridge over the Imjin River after the withdrawal of its 12th Regiment during the Battle of Kaesong–Munsan on 25 June. However, South Korean forces continued to hold their positions near the Imjin River, preventing the Korean People's Army from crossing the river.
26 June
Beginning on the afternoon of 25 June, reinforcements started arriving and were committed to battle in succession. The Infantry School Training Battalion was attached to the 11th Regiment, while the Korea Military Academy Training Battalion was assigned to the 13th Regiment, strengthening the main defensive line. The 15th Regiment (consisting of the regimental headquarters and the 3rd Battalion) was attached to the 3rd Battalion of the 20th Regiment and deployed along the Uijeon-ri–Bongilcheon line, which served as the final defensive line. Uijeon-ri is located in present-day Wollong-myeon, Paju, and Bongilcheon is located in present-day Bongilcheon-ri, Jori-eup, Paju. Colonel Paik Sun-yup, commander of the 1st Infantry Division, centered the division's defenses on Route No. 1, the principal avenue of approach. Anticipating the possibility that the main defensive line might be breached, he planned for the forces stationed along the Uijeon-ri line to cover the withdrawal of the frontline units and launch counterattacks.
On 26 June, North Korean tank units appeared on the front facing Papyeongsan in Paju, east of the division's sector. The regiment initially engaged the tanks with 2.36-inch M9 Bazooka, but when these proved ineffective, the troops resorted to close-quarters attacks using improvised explosive charges made from Mortar (weapon) shells and Grenade. Faced with these assaults, the tank unit withdrew, and a subsequent attack by North Korean infantry was also repelled in close combat.
Meanwhile, the 6th Division (North Korea) of the Korean People's Army, which had been attacking west of the 1st Division's sector, began an assault before dawn on 26 June, crossing the Imjin River railway bridge with five tanks leading the advance. The Republic of Korea Army's 11th Regiment resisted the attack, but by around 9:00 a.m., a hill north of Munsan Station had fallen to North Korean forces. As this hill overlooked a key route connecting to Route No. 1, the withdrawal routes of the 11th and 13th Regiments were effectively cut off.
However, after capturing the position, the North Korean forces halted their advance and waited for reinforcements. In response, the commander of the 1st Division immediately ordered a counterattack, and at approximately 10:00 a.m. the Korea Military Academy Training Battalion recaptured the hill. Based on information obtained from North Korean prisoners captured during the action, Colonel Paik Sun-yup concluded that only part of the enemy force had crossed the river. Beginning at around 1:00 p.m., he launched a counteroffensive involving three battalions, including the 11th Regiment and the Infantry School Training Battalion attached to it. The counterattack proceeded successfully, and the 1st Division succeeded in retaking its main defensive line.
However, by this time, Battle of Dongducheon had already fallen to North Korean forces, and the withdrawal of the 7th Infantry Division (South Korea), which had been defending the city, left the right flank of the 1st Division completely exposed.
The 1st Division (North Korea) of the Korean People's Army advanced toward the Gayeoul(present-day Nogok-ri, Baekhak-myeon, Yeoncheon County)–Jeokseong-myeon, Paju sector and launched another attack against the Republic of Korea Army's 13th Regiment with tanks spearheading the assault. The 13th Regiment was unable to halt the advance, and as the main force of the North Korean 1st Division pushed westward along Route 320, it began to threaten Munsan. In addition, North Korean tank units appeared in the rear area of the Republic of Korea Army's 11th Regiment, while attacks from the front also intensified. Ultimately, Colonel Paik Sun-yup abandoned efforts to hold the main defensive line and, at around 7:00 p.m. on 26 June, ordered a withdrawal to the Uijeon Defensive Line (the Bongilcheon Line), the division's final line of resistance. Under the cover of the 15th Regiment, which had been deployed near Uijeon-ri, the units stationed on the main defensive line successfully withdrew and were redeployed along the Uijeon Defensive Line.
27 June
Along the Uijeon Defensive Line, the 15th Regiment (including the 3rd Battalion of the 20th Regiment) was deployed at Uijeon-ri along Route No. 1, while the 13th Regiment was positioned at Donae-ri (present-day Wollong-myeon, Paju) along Route 307. The 11th Regiment was held in reserve, forming part of the final defensive line. Meanwhile, the 12th Regiment, which had been forced to disperse and withdraw during the border battles, was being reorganized at Geumcheon (then part of Siheung County).
Beginning at around 10:00 a.m. on 27 June, the main force of the Korean People's Army's 6th Division, spearheaded by tanks, launched an attack against the front of the Republic of Korea Army's 15th Regiment. The regiment had established an anti-tank defense line equipped with 57 mm recoilless rifles and 2.36-inch bazookas, but these weapons proved ineffective against T-34 tanks. As a result, the commander of the 3rd Battalion, 15th Regiment, personally led a suicide assault unit in close-quarters attacks against the tanks, destroying six of them. The Korean People's Army subsequently abandoned the attack and withdrew, while the 15th Regiment succeeded in overcoming its fear of enemy tanks.
During the fighting along the Uijeon Defensive Line, the front held by the 13th Regiment on the right flank of the 1st Division remained relatively quiet. However, from around 7:00 p.m., the regiment's defensive line came close to collapse under a Combined arms by the Korean People's Army's 1st Division. Nevertheless, after successfully destroying two North Korean tanks with 2.36-inch bazookas, the intensity of the enemy assault diminished, and the regiment was able to regain control of its defensive positions.
28 June
During the night of 27 June, taking advantage of heavy rain, North Korean forces launched a night attack that broke through the 1st Division's final defensive line, forcing the regimental units to withdraw from Bongilcheon under cover of darkness. At around the same time, Colonel Paik Sun-yup, commander of the 1st Division, was informed by an operational advisory group led by Major General Kim Hong-il (general), which had been dispatched from Republic of Korea Army Headquarters, of the deteriorating situation along the defensive line in the Mia-ri sector. Anticipating the worst-case scenario, the advisory group recommended that preparations be made for a withdrawal across the Han River (Korea). However, as the existing orders could not be altered, the 1st Division was instructed to hold its current positions for the time being.
At approximately 8:00 a.m. on 28 June, the 1st Division launched a counteroffensive in accordance with its previous orders. The 11th Regiment succeeded in recapturing most of the final defensive line, but the attack by the 13th Regiment on the division's right flank made little progress as it collided head-on with advancing North Korean forces. Colonel Paik Sun-yup committed the Seoul Independent Regiment and the 3rd Battalion of the 20th Regiment to restore the continuity of the defensive line. North Korean resistance on that day was not particularly strong, and the 1st Division assessed that it might even be possible to recapture its main defensive line.
However, at approximately 1:00 p.m. on 28 June, the Republic of Korea Army's final defensive line at Battle of Miari was breached by North Korean tanks. Later that afternoon, the 1st Division found its rear areas cut off and lost communications with Army Headquarters. With ammunition supplies also running low, Colonel Paik Sun-yup concluded that it was no longer possible to hold the division's positions and decided to withdraw. The subsequent operations led directly into the Battle of the Gimpo Peninsula and the Battle of Oryu-dong.
Uijeongbu–Mia-ri sector
The 7th Infantry Division (South Korea), which was responsible for defending the Uijeongbu sector, had been forced into a major withdrawal from the very first day of the war on 25 June. Its units had become dispersed, and Uijeongbu was under increasing threat. The Chief of Staff of the Republic of Korea Army, Chae Byeong-deok, recognized that Uijeongbu was effectively a corridor through which enemy tanks could fully exploit their mobility and shock effect. Moreover, the area lacked terrain favorable for defense, leaving the defending forces at an overwhelming disadvantage. At this stage of the war, the defense of the Uijeongbu axis had become the most critical problem facing the South Korean military.
26 June
Chief of Staff Chae Byeong-deok's counteroffensive plan was based on the assumption that the 2nd Infantry Division (South Korea)would be able to concentrate in the vicinity of Uijeongbu by the morning of 26 June, and that the 3rd Infantry Division (South Korea) and the 5th Infantry Division (South Korea) would also be able to assemble during the course of the day's fighting. However, Guerrilla warfareactivity in the rear areas severely hampered the movement and concentration of rear-echelon units. As a result, by the morning of 26 June, only the headquarters of the 2nd Infantry Division and two battalions of its 5th Regiment had managed to assemble near Uijeongbu. In addition, although the 7th Infantry Division had a total of five battalions available by the early hours of 26 June, this amounted to little more than the strength of a reinforced regiment.