First Battle of Naktong Bulge The First Battle of Naktong Bulge was an engagement between United States and North Korean forces early in the Korean War from August 5 – 19 , 1950 in the vicinity of Yongsan ( Yeongsan , Changnyeong county ) and the Naktong River in South Korea . It was a part of the Battle of Pusan Perimeter , and was one of several large engagements fought simultaneously . The battle ended in a victory for the United States after large numbers of US reinforcements destroyed an attacking North Korean division . On August 5 , 4th Infantry Division , North Korean People ' s Army ( KPA ) , crossed the Naktong River in the vicinity of Yongsan , attempting to cut US supply lines to the north as well as gaining a bridgehead into the Pusan Perimeter . Opposing it was the 24th Infantry Division of the Eighth United States Army . Over the next two weeks , American and North Korean forces fought a bloody series of engagements inflicting heavy casualties on one another in a confusing series of attacks and counterattacks , but neither side was able to gain the upper hand . In the end , the US forces , aided by reinforcements , air support and heavy weapons , destroyed the invading North Korean force which was hampered by lack of supply and high desertion rates . The battle was a turning point in the war for North Korean forces , which had seen previous victories owing to superior numbers and equipment . The American forces now had a numerical superiority and more equipment , including tanks and weapons capable of defeating the powerful North Korean T - 34 tanks . Background . Outbreak of war . Following the 25 June 1950 outbreak of the Korean War after the invasion of the Republic of Korea ( South Korea ) by its northern neighbor , the Democratic People ' s Republic of Korea ( North Korea ) , the United Nations decided to commit troops to the conflict on behalf of South Korea . The United States , a member of the UN , subsequently committed ground forces to the Korean peninsula with the goal of fighting back the North Korean invasion and to prevent South Korea from collapsing . However , US forces in the Far East had been steadily decreasing since the end of World War II , five years earlier , and at the time the closest forces were the 24th Infantry Division , headquartered in Japan . The division was understrength , and most of its equipment was antiquated due to reductions in military spending . Regardless , the 24th was ordered to South Korea . The 24th Infantry Division was the first US unit sent into Korea with the mission to take the initial " shock " of North Korean advances , delaying much larger North Korean units to buy time to allow reinforcements to arrive . The division was consequently alone for several weeks as it attempted to delay the North Koreans , making time for the 1st Cavalry and the 7th and 25th Infantry Divisions , along with other Eighth Army supporting units , to move into position . Advance elements of the 24th Infantry were badly defeated in the Battle of Osan on July 5 , the first encounter between American and North Korean forces . For the first month after the defeat of Task Force Smith , 24th Infantry was repeatedly defeated and forced south by superior North Korean numbers and equipment . The regiments of the 24th Infantry were systematically pushed south in engagements around Chochiwon , Chonan , and Pyongtaek . The 24th made a final stand in the Battle of Taejon , where it was almost completely destroyed but delaying North Korean forces until July 20 . By that time , the Eighth Army ' s force of combat troops were roughly equal to North Korean forces attacking the region , with new UN units arriving every day . North Korean advance . With Taejon captured , North Korean forces began surrounding the Pusan Perimeter from all sides in an attempt to envelop it . The 4th and 6th North Korean Infantry Divisions advanced south in a wide flanking maneuver . The two divisions attempted to envelop the UN ' s left flank , but became extremely spread out in the process . They advanced on UN positions with armor and superior numbers , repeatedly pushing back U . S . and South Korean forces . American forces were pushed back repeatedly before finally halting the North Korean advance in a series of engagements in the southern section of the country . Forces of the 3rd Battalion , 29th Infantry Regiment , newly arrived in the country , were wiped out at Hadong in a coordinated ambush by North Korean forces on July 27 , opening a pass to the Pusan area . Soon after , North Korean forces took Chinju to the west , pushing back the US 19th Infantry Regiment and leaving routes to the Pusan open for more North Korean attacks . US formations were subsequently able to defeat and push back the North Koreans on the flank in the Battle of the Notch on August 2 . Suffering mounting losses , the KPA force in the west withdrew for several days to re - equip and receive reinforcements . This granted both sides a reprieve to prepare for the attack on the Pusan Perimeter . Naktong Bulge . About north of the point where it turns east and is joined by the Nam River , the Naktong River curves westward opposite Yongsan in a wide semicircular loop . For most of this span , the Naktong is around wide and deep , allowing infantry to wade across with some difficulty but preventing vehicles from crossing without assistance . This perimeter was defended by a network of observation posts on the high ground , manned by 24th Infantry . Forces in reserve would counterattack any attempted crossings by KPA . Artillery and mortar fire units were also deployed so large amounts of fire could be delivered on any one spot . The division was extremely dispersed . Already understrength , it presented a very thin line . Battle . The 24th US Infantry Division , under the command of Major General John H . Church , occupied a region some long along the Naktong River . The 34th US Infantry Regiment occupied the southern half , west of Yongsan while the 21st US Infantry Regiment occupied the northern half , west of Changyong . The 19th US Infantry Regiment , meanwhile , was re - equipping in the rear of the lines . In all , the 24th and its supporting units had a strength of 14 , 540 on August 5 . Opposing the 24th Infantry was the 4th North Korean Infantry Division , under the command of Major General Lee Kwon Mu . Both Mu and his division were highly decorated for their exploits so far in the war , particularly during the First Battle of Seoul . By August 4 the 4th Division had concentrated all of its regiments in the vicinity of Hyopch ' on . It stood at a strength of about 7 , 000 with 1 , 500 in each infantry regiment . North Korean attack . At midnight on the night of August 5 – 6 , 800 North Korean soldiers of the 3rd Battalion , 16th Regiment waded across the river at the Ohang ferry site , south of Pugong - ni and west of Yongsan , carrying light weapons and supplies over their heads or on rafts . A second force attempted to cross further north but was hit with machine gun and artillery fire , falling back in confusion . At 0200 on August 6 , the North Koreans began engaging the forces of 3rd Battalion , 34th Infantry and moved forward after a small fight , attempting to penetrate the lines to Yongsan . North Korean infantry forced 3rd Battalion back , and the American battalion abandoned its command post to consolidate its position . The attack caught the Americans by surprise as US commanders expected the North Koreans to attempt a crossing further north . The landing threatened to split the American lines and disrupt supply lines to positions further north . Subsequently the North Koreans were able to capture a large amount of American equipment . US counterattack . The 34th Infantry ' s regimental headquarters ordered the 1st Battalion to counterattack the North Koreans . When 1st Battalion arrived at 3rd Battalion ' s former command post , it was ambushed by KPA troops on the high ground . C Company , the first to arrive , suffered over fifty percent casualties . A and B Companies counterattacked with tanks and armor , eventually rescuing the beleaguered C Company . At around 20 : 00 , A Company made contact with L Company , 3rd Battalion , still in its positions on the river , radioing that the North Koreans had penetrated eastward north of the Yongsan - Naktong River road to Cloverleaf Hill , but had not yet crossed south of the road to Obong - ni Ridge . The North Koreans had penetrated east of the Naktong and halfway to Yongsan . Several units of the 34th Regiment began to retreat north and into the 21st Infantry ' s lines , but Church ordered them turned around . He also ordered the 19th Infantry to counterattack west along the northern flank of the 34th Infantry to help oppose the KPA . Although the 24th Infantry was repulsed closer to the river , inland the 19th Infantry trapped about 300 North Koreans in a village and killed most of them . The 1st Battalion , 34th Infantry , had managed to block the North Korean ' s advance to Yongsan while the 19th Infantry was able to push it back and inflict substantial casualties . However , by the evening of August 6 , KPA held firmly on to their bridgehead . Attempted crossings that night were repulsed to the south by South Korean forces , but an unknown number of reinforcements were moved across the river the night of August 6 – 7 . On August 7 – 8 , the North Koreans tried to move two more battalions across the river to the north , but were repulsed by 21st Infantry , which was still in place . The KPA battalions were shifted south to cross at the bridgehead , instead . By August 8 , an estimated regiment of North Korean troops were across the Naktong . Stalemate . American counterattacks continued into the morning of August 7 , but the gains were slow , hampered by the hot weather and a lack of food and water . The North Koreans were able to press forward and regain the Cloverleaf Hill and Oblong - ni Ridge , critical terrain astride the main road in the bulge area . By 16 : 00 that day , the 9th Infantry Regiment , 2nd US Infantry Division , a unit newly arrived in Korea , was sent to the region . Church immediately ordered it to attack the North Korean salient at the bulge . 9th Infantry was fresh and well - equipped . They were also inexperienced , many of their number being reservist s . Despite a tenacious attack , the 9th Infantry was only able to regain part of Cloverleaf Hill before intense fighting stalled its movement . North Korean forces began making gains in the hills along the river adjacent to their bridgehead , against positions of the 34th Infantry . Coordinated attacks pushed A Company to the north back from their hills with heavy casualties on August 7 . K Company to the south was also attacked but held its line , reinforced by L Company on August 10 . Fighting continued for several days , resulting in heavy casualties as both sides captured and recaptured the hills along the Naktong , neither side able to gain a decisive advantage against the other . Task Force Hill . In an attempt to destroy the North Korean bridgehead , Church assembled a large force under the 9th Infantry Regiment . Dubbed " Task Force Hill " , this force comprised the 9th , 19th , and 34th Infantry Regiments as well as 1st Battalion , 21st Infantry , plus supporting artillery and other attached units . It was assigned to drive the North Koreans from the east bank of the river on August 11 . Commanding the task force was Colonel John G . Hill , the Commanding Officer of the 9th Infantry Regiment . The 4th North Korean Division , meanwhile , had constructed underwater bridge s of sandbags , logs , and rocks , finishing the first on August 10 . 4th Division used it to move trucks and heavy artillery as well as additional infantry and a few tanks across the river . By the morning of August 10 , an estimated two KPA regiments were across the river and occupying fortified positions . Supplies continued to stream in through rafts . Task Force Hill mounted its attack , but was once again unable to make progress due to the newly established artillery . Its directive to attack quickly became one to dig in and hold its ground , and by nightfall the entire 4th North Korean Division was across the river . On August 10 , elements of 4th North Korean began to move south , outflanking Task Force Hill . The next day , scattered North Korean elements attacked Yongsan . KPA repeatedly attacked at night , when American soldiers were resting and had greater difficulty resisting . Reinforcements . On August 12 , General Walton Walker , in command of the Eighth Army , dispatched part of the 27th Infantry Regiment , 25th US Infantry Division , to attack north from the 25th Division ' s zone to drive off 4th North Korean Division troops moving into Yongsan . Simultaneously , Church assembled all the combat service support soldiers he could and formed them into a combat unit to block further penetration of North Korean forces , which were setting up roadblocks on the roads from Yongsan . Additional reinforcements poured in . The rest of the 27th Infantry moved in , as well as a battalion from the 23rd Infantry Regiment , 2nd US Infantry Division . These were able to push North Korean infiltrators out of Yongsan and back to their firmly held positions at Cloverleaf Hill . On August 14 , following an artillery barrage , Task Force Hill launched a direct assault on these positions . Fighting continued the entire day in a fierce series of attacks and counterattacks in which both sides , already at far reduced strength , inflicted large numbers of casualties . However , Task Force Hill ' s second attack was just as unsuccessful as its first . Casualties among officers was high in the fight , and the disorganization that followed meant most of the units in the fight could not communicate to coordinate any large actions . It became a battle of attrition by August 15 as neither 4th North Korean Division nor Task Force Hill were able to get the upper hand in the fight , which in several cases erupted in desperate hand - to - hand combat . Casualties mounted and a frustrated Walker ordered the 5 , 000 - man 1st Provisional Marine Brigade to the area to turn the tide . The brigade moved from the Masan region in the middle of a counteroffensive being conducted by the 25th US Infantry . The 4th North Korean Division in the meantime was suffering serious logistical setbacks from lack of food , equipment , ammunition and , weapons . Conscripts from local South Korean villages were brought in to replace mounting losses . There was also virtually no provision for the wounded in the division , and the North Korean forces began to come apart under these stresses . Still , the division ' s morale remained relatively high and General Lee refused to withdraw . Destruction of the bridgehead . The 1st Marine Provisional Brigade , in conjunction with Task Force Hill , mounted a massive offensive on Cloverleaf Hill and Obong - ni on August 17 . The offensive began at 0800 on August 17 , with US forces unleashing all heavy weapons available to them against the North Korean positions ; artillery , mortars , M26 Pershing tanks , and airstrike s . At first , tenacious KPA defense halted the Marines who responded with artillery , raking Cloverleaf Hill . Heavy indirect fire forced the North Koreans out of their positions before the Marines and Task Force Hill eventually overwhelmed them , one hill at a time . The Marines approached Obong - ni first , destroying resistance on the slope with an airstrike and a barrage from US tanks , but strong resistance caused heavy casualties , and they had to withdraw . The 18th North Korean Regiment , in control of the hill , mounted a disastrous counterattack in hopes of pushing the Marines back . The division ' s tactics of cutting off supplies and relying on surprise , which had provided them so much success up to this point , failed in the face of massive US numerical superiority . By nightfall on August 18 , 4th North Korean Division had been annihilated ; huge numbers of deserters had weakened its numbers during the fight , but by that time , Obong - ni and Cloverleaf Hill had been retaken by the US forces . Scattered groups of North Korean soldiers fled back across the Naktong , pursued by American planes and artillery fire . The next day , the remains of 4th Division had withdrawn across the river . In their hasty retreat , they left a large number of artillery pieces and equipment behind which the Americans later pressed into service . Aftermath . The battle caused massive casualties for both sides . By the end of the fight , 4th North Korean Division had been completely destroyed , with only 300 or 400 men in each of its regiments . Of its original 7 , 000 men , the regiment now had a strength of only 3 , 500 , having suffered over 1 , 200 killed . Several thousand of the members of the division deserted during the fight . Most of these men were South Korean civilians forcibly conscripted into the North Korean army . 4th Division would not recover until much later in the war . The battle represented a new phase in the war for the North Koreans . Their numerical superiority was gone , and their strategy of attacking supply lines and rear formations of US units was no longer effective without overwhelming numbers . Additionally , the advantage the T - 34 tank had once provided was also gone ; American units were now well equipped with effective anti - tank weapons , as well as larger numbers of tanks of their own . Subsequently , all 4th Division ' s T - 34s were quickly knocked out before they could inflict much damage . The 9th Infantry and supporting units sustained 57 killed , 106 wounded , two captured , and 13 missing , a total of 180 casualties . The 21st Infantry suffered around 30 killed and 70 wounded , the 19th Infantry around 450 casualties , and the 34th Infantry around 400 . The 27th Infantry reported around 150 . The 1st Provisional Brigade reported 66 Marines dead , 278 wounded , and one missing . In total , American forces suffered around 1 , 800 casualties during the conflict , including about a third them killed . In memory of the battle at Naktong Bulge , as well as other conflicts along the Pusan Perimeter and the Battle of Taegu , the South Korean government set up the Nakdong River Battle Museum along the river in the vicinity of the conflict in 1979 , which includes a number of artifacts from the Korean War as well as a memorial to those killed during the war .