Battle of the Notch The Battle of the Notch was an engagement between United States and North Korean forces early in the Korean War on August 2 , 1950 in southern South Korea . The fight ended in a victory for the United States after North Korean forces attempting to assault the US position were blocked and repelled repeatedly , suffering heavy casualties . Reeling from the Hadong Ambush and being driven from the city of Chinju , the US Army ' s 19th Infantry Regiment , 24th Infantry Division scrambled to protect the pass into Masan , the final South Korean city before the Naktong River , where the UN was holding its Pusan Perimeter in place . North Korean and US forces unexpectedly ran into one another and a confused battle ensued . American forces were better equipped with heavy weapons and armor thanks to newly arrived equipment in the country , and their better ground during the battle allowed them to repel North Korean advances . The North Korean force eventually withdrew after several unsuccessful attacks , having suffered heavy casualties . As it was disengaging from Masan , US Air Force aircraft caught the North Korean truck columns as they were retreating , inflicting significant damage on them and producing further casualties . This fight , with a number of smaller engagements in the region , effectively stopped the North Korean offensive on the southern flank of the Pusan Perimeter . It also gave both sides a reprieve from the fighting to resupply and re - enforce before engaging in the Battle of Pusan Perimeter shortly after . Background . Outbreak of war . Following the 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 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 of the Eighth United States Army , which was headquartered in Japan . The division was understrength , and most of its equipment was antiquated due to reductions in military spending . Regardless , the 24th Infantry Division was ordered into 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 follow on forces to arrive . The division was consequently alone for several weeks as it attempted to delay the North Koreans , making time for the 7th Infantry Division , 25th Infantry Division , 1st Cavalry Division , and other Eighth Army supporting units to move into position . Advance elements of the 24th Infantry Division were badly defeated in the Battle of Osan on July 5 , during the first battle between American and North Korean forces . For the first month after the defeat of Task Force Smith , 24th Infantry Division soldiers were repeatedly defeated and forced south by the North Korean force ' s superior numbers and equipment . The regiments of the 24th Infantry Division were systematically pushed south in battles around Chochiwon , Chonan , and Pyongtaek . The 24th Infantry Division made a final stand in the Battle of Taejon , being almost completely destroyed but delaying North Korean forces from advancing 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 the effort of surrounding the Pusan Perimeter from all sides in an attempt to envelop it . The North Korean 4th Infantry Division and the North Korean 6th Infantry Division advanced south in a wide maneuver . The two divisions were coordinating to envelop the UN ' s left flank and were extremely spread out . They advanced on UN positions pushing back US and South Korean forces repeatedly . 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 , leaving open a pass to the Pusan area . Soon after , Chinju to the west was taken , pushing back the 19th Infantry Regiment and leaving routes to the Pusan open for North Korean forces . Reeling from the loss , UN planners hastily moved reserve forces to the southwest to repel North Korean advances . Several US infantry regiments as well as the command post of the 24th Infantry Division moved to establish new positions to prevent North Korean forces from advancing from Chinju . American forces moved to defend the city of Masan , the last key city before the North Koreans reached the perimeter . Located in the mountainous region along South Korea ' s southern coast , Masan was accessible by two routes from the west . Major General John H . Church , the 24th Infantry Division ' s commander , emplaced the 19th Infantry Regiment and the 27th Infantry Regiment in the area to defend Masan . Eventually , the 27th set up along the southern entrance while the 19th Infantry covered the north , in a pass known as " The Notch , " southwest of Chungam - ni . The entire 19th Infantry Regiment , reeling from the fight at Chinju and attempting to hold back North Korean advances , fell back to the Notch . Battle . The 1st Battalion , 19th Infantry was assigned to hold the Notch and the high ground on the right flank , to the northwest . Republic of Korea troops led by Colonel Min would hold the high ground to the southwest of the Notch . Meanwhile , 2nd Battalion , 19th Infantry withdrew to reserve positions at the northern base of the pass . During the evening of July 31 , 1st Battalion , 29th Infantry also arrived in the region . More importantly , A Company of the 8072nd Medium Tank Battalion , armed with M4 Sherman medium tanks rebuilt in Japan , arrived at Masan , some of the first heavy armor the UN had in the war . One platoon of A Company ' s tanks went to the 27th Infantry in the south while the 19th Infantry in the north got the other half . This put the force of the 19th Infantry and supporting units at 2 , 335 under the command of Colonel Ned D . Moore , excluding the South Korean forces . The number of North Korean forces committed to the region is not known , however later research suggests that the North Korean 6th Division committed at least a battalion to the fight , and it is likely that an entire regiment was ordered to advance on the Notch and Masan . This would put the range of North Korean forces involved in the battle between 500 and 2 , 000 . Attack . At 06 : 45 on August 2 , C Company , 1st Battalion , 19th Infantry began to move out from its positions on a reconnaissance patrol supported by tanks and armored cars . Before the armored column left the lines , it ran head - on into a North Korean attack starting on the Notch , as mortar fire and three heavy machine guns opened up on it from below the crest of the pass . The road before the pass erupted into a frantic and confused struggle , C Company in the lead was struck with machine gun fire , killing most of its 1st Platoon before the men could disembark from their trucks . American soldiers who dove for cover in the ditches along the road found North Korean soldiers already in cover there . The lead M4 was struck with mortar fire and destroyed , while anti - tank weapons set at least one American truck on fire . During this fight , advancing North Korean troops captured at least a few of the surprised American soldiers , using them as human shield s when advancing up the high ground where the rest of the UN force was firing down at them . In the end , the initial ambush cost the Americans about 30 casualties . C Company overcame several North Korean attempts to cut them off before withdrawing back to the American lines . American forces were quick to counter the attack . M20 recoilless rifle s destroyed the machine gun positions , and American mortars began firing on any North Korean positions they could locate . However , North Korean forces were quick to advance up the Notch , to the crest of the hill that made up the pass . There , the discovered B Company , 19th Infantry , encamped . The 19th Infantry was apparently not prepared for combat , as North Korean forces were able to hit the American force and drive it off the hill , killing several of the American soldiers with bayonet s . At about 12 : 00 , B Company was driven from the crest of the Notch , and further confusion erupted when US Air Force aircraft accidentally strafed the retreating B Company . Neighboring positions also mistakenly attacked B Company , which retreated with 12 killed . South Korean forces , meanwhile , had emplaced in the wrong position , a mile too far south , and were not in contact with 19th Infantry . The South Korean forces were subsequently hit with friendly and enemy fire , and in the confusion the 19th Infantry attempted to block the South Koreans from advancing , thinking them enemy forces . North Korean snipers were able to infiltrate the rear of the position and kill five UN soldiers with shots to the back of the head . However American forces repelled several advances on the right flank . The M4 Shermans gave the American force a superiority in armor over the North Koreans for the first time , and were crucial in pushing back each attempted North Korean advance . North Korean infantry , unsupported by armor of their own , suffered heavy casualties from the American forces in their positions on the high ground . North Korean withdrawal . Fighting at the Notch continued through the afternoon , but , the attack still unsuccessful , the North Korean troops withdrew suddenly in the mid - afternoon , allowing American forces to recover most of the casualties and vehicles from the Notch . In the meantime , they set up roadblocks to prevent further North Korean attacks from moving down the road . North Korean forces disengaged from the fight without attempting to flank the Americans , and by nightfall they were out of the region . In the meantime , the 27th Infantry Regiment surprised a large column of North Korean forces advancing on the south road and captured many trucks of supplies . During the North Koreans ' retreat from the two roads , US Air Force planes mounted an airstrike against the North Koreans and inflicted heavy casualties . Aftermath . The American forces reported 57 killed , 37 wounded , 17 missing and 6 captured , for a total of 117 casualties from the 19th and 29th Infantry Regiments . This number was far lighter than casualties for other unit actions of similar size so far in the war . North Korean casualties are unknown but believed to be far heavier than the American force . Actions in the Notch , as well as attacks on the region for the next few days are known to have largely destroyed the North Korean 6th Division , and over 50 percent of its force became casualties in the fighting . The fight was one of the first victories for American forces in repelling the North Korean advance . In stopping the North Korean advance at the Notch and around Masan , the UN forces were able to halt the progress of the North Korean 4th and 6th Divisions , grounding their flanking moves to a halt and forcing them to withdraw to rebuild and re - supply . In the meantime , the American forces along the perimeter were being reinforced by heavier infantry and armor formations every day . The North Korean defeat and retreat around the Masan region allowed both sides several critical days of reprieve from battle . This would end when the North Korean force began its final offensive on the UN forces in its coordinated assault on the Pusan Perimeter .