Battle of Nam River

The Battle of Nam River was an engagement between United Nations (UN) and North Korean (NK) forces early in the Korean War from August 31 to September 19, 1950, in the vicinity of the Nam River 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 Nations after large numbers of United States (US) and Republic of Korea (ROK) troops were able to repel a North Korean attack across the river.

Positioned in defense of Masan during the Battle of Masan, the US 35th Infantry Regiment, 25th Infantry Division took up positions along the Nam River, one of the many tributaries of the Naktong River on the southern flank of the Pusan Perimeter. The North Korean People's Army's 7th Division effected a crossing of the river on August 31, and though the 35th Infantry was able to stem the North Korean advance, thousands of North Korean troops were able to exploit a hole in the line and surround the regiment. What followed was an intense battle in which the US and North Korean units were heavily engaged all along and behind the Kum River line. Eventually, though, the North Korean force was routed and defeated by the US troops.

During the battle, the 35th Infantry was instrumental in forcing back the North Korean division and preventing it from advancing to capture Pusan. The delay was enough for UN forces to counterattack Inchon, effectively defeating the entire North Korean army at the Pusan Perimeter. The 35th Infantry's performance in the battle earned the regiment a Presidential Unit Citation.

Background

Outbreak of war

Following the June 25, 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.

Task Force Smith arrives in 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 US 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, the 24th Infantry Division 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 was 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 US 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 Korean People's Army 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.

Attack on Masan

Main article: Battle of Masan

M24 Chaffee light tanks wait for a North Korean attack near Masan

During the lull in fighting following the Battle of the Notch, Eighth Army commander Lieutenant General Walton Walker ordered the US 25th Infantry Division, under Major General William B. Kean, to take up defensive positions on the Pusan Perimeter southern flank west of Masan. By August 15, the 25th Infantry Division had moved into these positions. Rough terrain west of Masan limited the choice of the positions. The mountain group west of Masan was the first readily defensible ground east of the Chinju pass. The 2,000 feet (610 m) mountain ridges of Sobuk-san dominated the area and protected the Komam-ni-Haman-Chindong-ni road, the only means of north-south communication west of Masan.

To the north, from the Masan-Chinju highway to the Nam River, were several easily defensible positions. The most favorable was the high ground near Chungam-ni, which controlled an important junction connecting the Masan road with the road over the Nam River to Uiryong. It was essential for the US 25th Infantry Division's right flank to connect with the left flank of the US 24th Infantry Division at the confluence of the Nam and the Naktong Rivers. Therefore, the 25th Infantry Division also moved to protect the Komam-ni road intersection where the Chindong-ni-Haman road met the Masan-Chinju highway.

Meanwhile, the NK 6th Division was ordered to await reinforcements before continuing the attack. From north to south, the division had its 13th, 15th, and 14th Regiments. The first replacements arrived at Chinju on about August 12. Approximately 2,000 unarmed South Koreans conscripted in the Seoul area joined the division by August 15. At Chinju, the NK 6th Division issued them grenades and told the recruits they would have to pick up weapons from killed and wounded soldiers on the battlefield. Another group of 2,500 replacements conscripted in the Seoul area joined the 6th Division on August 21, bringing the division's strength to approximately 8,500 men. In the last week of August and the first week of September, 3,000 more recruits conscripted in southwest Korea joined the division. The 6th Division used this last body of recruits in labor details and only later employed them as combat troops. As a part of the North Korean build-up in the south, the untried NK 7th Division also arrived near Masan with another 10,000 men. The 7th Division occupied key ports to protect the 6th Division against possible amphibious landings in its rear.

On August 31, 1950, the 25th Division held a front of almost 30 miles (48 km), beginning in the north at the Namji-ri bridge over the Naktong River and extending west on the hills south of the river to the Nam's confluence with it. It then bent southwest up the south side of the Nam to where the Sobuk-san mountain mass tapered down in its northern extremity to the river. There the line turned south along rising ground to Sibidang-san, crossed the saddle on its south face through which passed the Chinju-Masan railroad and highway, and continued southward up to Battle Mountain and on to P'il-bong. From P'il-bong the line dropped down spur ridge lines to the southern coastal road near Chindong-ni. The US 35th Infantry Regiment held the northern 26,000 yards (24,000 m) of the division line, from the Namji-ri bridge to the Chinju-Masan highway. The regiment was responsible for the highway. The regiment's weakest point was a 3 miles (4.8 km) gap along the Naktong River between most of F Company on the west and its 1st Platoon to the east. This platoon guarded the Namji-ri cantilever steel bridge on the division's extreme right at the boundary with the US 2nd Infantry Division across the Naktong River. South of the highway, the US 24th Infantry Regiment held the high ground west of Haman, including Battle Mountain and P'il-bong. Colonel John L. Throckmorton's US 5th Infantry Regimental Combat Team held the southern spur of Sobuk-san to the coastal road at Chindong-ni. From Chindong-ni some ROK Marine Corps units continued the line to the southern coast. Kean's 25th Division command post was at Masan, the 35th Infantry command post was on the east side of the Chirwon-Chung-ni road, the 24th Infantry command post was at Haman and Throckmorton's command post was at Chindong-ni. By August 31, the division was suffering manpower shortages, and a limited number of KATUSAs were brought in to replenish its ranks.

Battle

See also: The Great Naktong Offensive

In the southern part of its sector, where the US 25th Infantry Division held the UN line, the NK I Corps planned a strong attack, coordinating it with an attack against the US 2nd Infantry Division to the north. The North Korean 6th and 7th Divisions received their attack orders on August 20. The North Korean operations order called for the NK I Corps to assault all along the line at 22:00 on August 31. The 6th Division, farthest south on the right flank, was to attack through Haman, Masan, and Chinhae and capture Kumhae, on the west side of the Naktong River delta 15 miles (24 km) from Pusan, by September 3. The division zone of attack was to be south of the Chinju-Komam-ni-Masan highway. The 7th Division, next in line north of the 6th Division, was to attack north of the Masan highway, wheel left to the Naktong, and wait for the 6th Division on its right and the NK 9th Division on its left to join it. Part of the 7th Division was concentrated in the Uiryong area west of the Nam River. This plan pitted the 6th Division against the US 24th Infantry Regiment and the 7th Division against the US 35th Infantry Regiment. As a part of this plan, the NK 6th Division had been engaging the 24th Infantry at Battle Mountain for several weeks prior, to a stalemate. Kean, aware of a pending offensive and distrusting the 24th Infantry's ability, began to compile a report on the regiment's performance to determine how to improve its capabilities. The North Korean 6th Division struck the 24th Infantry at Haman on August 31, and pushed it back after heavy engagements. The NK 6th Division and the US 24th Infantry Regiment remained locked in a bitter fight for the next week.

North Korean crossing

Meanwhile, the North Korean 7th Division troops committed all of their effort into attacking the US 35th Infantry line. At 23:30 on August 31, a North Korean SU-76 self-propelled high-velocity gun from across the Nam fired shells into the position of G Company, 35th Infantry, overlooking the river. Within a few minutes, North Korean artillery was attacking all front-line rifle companies of the regiment from the Namji-ri bridge west. Under cover of this fire a reinforced regiment of the NK 7th Division crossed the Nam River and attacked F and G Companies, 35th Infantry. Other North Korean soldiers crossed the Nam on an underwater bridge in front of the paddy ground north of Komam-ni and near the boundary between the 2nd Battalion, led by Lieutenant Colonel John L. Wilkins, Jr., holding the river front and Lieutenant Colonel Bernard G. Teeter's 1st Battalion holding the hill line that stretched from the Nam River to Sibidang-san and the Chinju-Masan highway. The 35th Infantry, facing shortages of materiel and reinforcements, was under-equipped but nonetheless prepared for an attack.

The T-34 tank was standard armor used by the North Korean Army in 1950 and was also present at Masan

At the river ferry crossing site in the low ground between these two battalions, the regimental commander placed 300 ROK National Police, expecting them to hold there long enough to serve as a warning for the rest of the forces. Guns from the flanking hills there could cover the low ground with fire. Back at Komam-ni he held the 3rd Battalion ready for use in counterattack to stop an enemy penetration should it occur. Unexpectedly, the ROK police companies near the ferry scattered at the first North Korean fire. At 00:30, North Korean troops streamed through this hole in the line, some turning left to take G Company in its flank and rear, and others turned right to attack C Company, which was on a spur of ground west of the Komam-ni road. Elements of C and D Companies formed a defense line along the dike at the north edge of Komam-ni where US tanks joined them at dawn. The North Koreans, however, did not drive for the Komam-ni road fork 4 miles (6.4 km) south of the river as the US commander, Lieutenant Colonel Henry Fisher had expected; instead, they turned east into the hills behind 2nd Battalion.

The position of B Company, 35th Infantry, on the 1,100 feet (340 m) Sibidang-san, flanked the Masan road 2 miles (3.2 km) west of Komam-ni and gave the company a commanding view over the surrounding countryside. It was a key position in the 25th Division line, and Kean was aware the North Koreans would consider it important ground to target for attack. The North Korean preparatory barrage there lasted from 11:30 to midnight. Under this cover, two battalions of the NK 13th Regiment, 6th Division, moved up within 150 yards (140 m) of the American foxholes. At the same time, North Korean T-34 tanks, SU-76 self-propelled guns, and antitank guns moved toward Komam-ni on the road at the foot of Sibidang-san. An American M4A3 Sherman tank there destroyed a T-34 just after midnight, and a 3.5-inch bazooka team destroyed a self-propelled gun and several 45 mm antitank guns.

On the crest of Sibidang-san, an antipersonnel minefield stopped the first North Korean infantry assault. More attacks followed in quick succession, all of which were repulsed by the US troops' superior firepower. By 02:30 the B Company riflemen were so depleted of ammunition that they began stripping machine-gun bullets from the ammunition belts and using them in their rifles. The 1st Platoon of C Company, at the base of the mountain behind B Company, climbed Sibidang-san in 45 minutes with an ammunition resupply for the company. Just before dawn the North Korean attack subsided. Daylight revealed a vast amount of abandoned North Korean equipment scattered on the slope just below the crest, including 33 machine-guns. Among the North Korean dead was the commanding officer of the NK 13th Regiment.

At daybreak on September 1, a relief force of C Company headquarters troops, led by American tanks, cleared the road to Sibidang-san and resupplied the 2nd Platoon, B Company, with ammunition just in time for it to repel another North Korean assault. This failed assault resulted in the killing of 77 and capturing of 21 North Koreans. Although the 35th Infantry held all its original positions, except that of the forward platoon of G Company, 3,000 North Korean soldiers were behind its lines. The farthest eastern penetration reached the high ground just south of Chirwon overlooking the north-south road there.

In the meantime, the NK 6th Division had made breakthroughs in the US 24th Infantry sector to the south, overwhelming the regiment and forcing it back. The 2nd Battalion, 24th Infantry, on the ridges overlooking Haman, was pushed back as its soldiers retreated without orders. Survivors from the 24th Infantry's 1st and 2nd battalions later appeared in the 35th's lines, and the regimental commanders found that the entire regiment had crumbled under North Korean attack. Kean ordered the 1st Battalion, 27th Infantry to move in and help restore the 24th's position.

North Korean infiltration

In a counterattack after daylight, K Company and tanks had partially regained control of the ridges overlooking Haman, but not completely. Large numbers of North Koreans were behind the battle positions of the 35th Infantry as far as the Chirwon-ni and Chung-ni areas, 6 miles (9.7 km) east of Komam-ni and the front positions. The North Koreans continued to cross the Nam River after daylight on September 1 in the general area of the gap between the 1st and 2nd Battalions. UN observation aircraft spotted an estimated four companies crossing there and directed fire of the 64th Field Artillery Battalion on the crossing force, which destroyed an estimated three-fourths of it. Fighter planes then strafed the survivors. Later another large group of North Koreans were spotted in the open at the river later in the day and American aircraft directed artillery fire on the column, with an estimated 200 North Korean casualties.

The NK I Corps plan of attack below the Nam River was for its 6th Division to push east along the main Chinju-Komam-ni-Masan highway through the 1st Battalion, 35th Infantry, and at the same time for major elements of its 7th Division to swing southeast behind the 2nd Battalion, 35th Infantry, and cut the Chirwon road. This road crossed the Naktong River over the cantilever steel bridge at Namji-ri from the US 2nd Infantry Division zone and ran south through Chirwon to join the main Masan highway 8 miles (13 km) east of Komam-ni near the village of Chung-ni, 4 miles (6.4 km) northwest of Masan. These two avenues of approach, the Komam-ni-Masan highway and the Chirwon road converging at Chung-ni, formed the axes of their attack plan.

US Engineer troops counterattacking up the secondary road toward Chirwon during September 1 made slow progress, and North Koreans stopped them in the early afternoon. The 35th Infantry was now surrounded by forces of the NK 6th and 7th Divisions, with an estimated three battalions of them behind its lines. Speaking later of the situation, Fisher said, "I never intended to withdraw. There was no place to go. I planned to go into a regimental perimeter and hold."

US 2-27th Infantry counterattack

Troops of the 2nd Battalion, 27th Infantry traverse the recaptured Engineer Road.

By mid-afternoon, Kean felt that the situation was a severe threat to the integrity of the division's line. He ordered the 2nd Battalion, US 27th Infantry Regiment, to attack behind the 35th Infantry, because a large part of the division's artillery there was under direct North Korean infantry attack. During the morning hours of September 1, when the NK 7th Division troops had attacked, the first American unit they encountered was G Company, 35th Infantry, at the north shoulder of the gap. While some North Korean units peeled off to attack G Company, others continued on and engaged E Company, 2 miles (3.2 km) downstream from it, and still others attacked scattered units of F Company all the way to its 1st Platoon, which guarded the Namji-ri bridge. There, at the extreme right flank of the 25th Division, this platoon drove off a North Korean force after a fierce fight. By September 2, E Company had destroyed most of a North Korean battalion in heavy fighting.

Of all the 2nd Battalion units, G Company received the hardest blows. Before dawn of September 1, North Korean troops had G Company platoons on separate hills under heavy assault. Shortly after 03:00 they overran the 3rd Platoon, Heavy Mortar Company, and drove it from its position. These mortarmen climbed Hill 179 and on its crest joined the 2nd Platoon of G Company. Meanwhile, the 3rd Platoon of G Company, on a low hill along the Nam River 4 miles (6.4 km) from its juncture with the Naktong River, was also under close quarters attack. After daylight, Captain LeRoy E. Majeske, G Company commander, requested artillery concentrations and air strikes, but they were slow to come. At 11:45, the North Koreans had almost reached the crest of the hill, and only a narrow space separated the two forces. A few minutes later Majeske was killed, and Second Lieutenant George Roach, commanding the 3rd Platoon, again reported the situation and asked for an air strike. The US Air Force delivered the strike on the North Korean held side of the hill, and this checked the assaults. By this time many North Korean troops had captured and occupied foxholes in the platoon position and from there threw grenades into other parts of the position. One of the grenades killed Roach early in the afternoon. Sergeant First Class Junius Poovey, a squad leader, now assumed command. By 18:00, Poovey had only 12 effective troops left in the platoon, 17 of the 29 men still living were wounded. With ammunition almost gone, Poovey requested and received authority to withdraw into the main G Company position. After dark, the 29 men, three of them carried on stretchers, withdrew, covered by the arrival of US tanks. The group reached the G Company position on Hill 179 at 23:30.

Stalemate

While G Company held its positions on Hill 179 on September 2 against North Korean attack, 2nd Battalion, 27th Infantry started an attack northwest toward it at 17:00 from the Chung-ni area. The battalion made slow progress against formidable North Korean forces. The night was extremely dark and the terrain along the Kuhe-ri ferry road was mountainous. After fighting throughout the night, the battalion reached a position south of the original defensive positions of G Company, 35th Infantry the next day at 15:00. A coordinated attack by US armor, artillery, air, and infantry got under way and by 18:00 the battalion had re-established the battle line. In this attack the 2nd Battalion, 27th Infantry, killed 275 North Koreans and recovered a large part of the equipment G Company had lost earlier.

The 2nd Battalion, 27th Infantry remained on the regained positions during the night of September 3. At 08:00 the next morning, G Company, 35th Infantry, relieved it on the regained positions and started its attack back up the supply road. While this was in progress, word came that the North Koreans had again driven G Company from its newly reestablished position. The 2-27th Infantry turned around, attacked, and once more restored the G Company positions. By 12:00 September 4, the 2-27th Infantry again turned over these positions to G Company and resumed its attack to the rear along the road in the gap between the 1st and 2nd Battalions, 35th Infantry. Almost immediately it was in contact with North Korean forces. Soon North Korean machine-guns were firing on the US troops from three directions. Torrential rains fell and observation became poor. By this time, the 2-27th Infantry was running short of ammunition. The commander ordered the battalion to withdraw 500 yards (460 m) to favorable terrain so that it could resupply.

Resupply proved to be a difficult task. The battalion had cleared the supply route two days previously in its attack to the G Company position but now it was closed again. The battalion commander requested air supply and the next morning, September 5, eight transport planes accomplished the resupply and the 2nd Battalion, 27th Infantry, was ready to resume its attack to the rear. By evening it had cleared the supply road and adjacent terrain of North Korean penetration for a distance of 8,000 yards (7,300 m) to the rear of G Company's front-line positions. There the 2-27th Infantry received orders to halt and prepare to attack northeast to link up with the 1st Battalion, 27th Infantry.

US 3-27th Infantry moves up

After 2-27th Infantry had left the Chung-ni area on September 2 in its attack toward G Company, the North Koreans attacked the 24th Infantry command post and several artillery positions. To meet this new situation, General Kean ordered the remaining battalion of the 27th Infantry, commanded by Lieutenant Colonel George H. DeChow, to attack and destroy the North Koreans operating there.

The 27th Infantry's command post beneath a bridge near Haman.

After an early morning struggle on September 3 against several hundred North Koreans in the vicinity of the artillery positions, DeChow's battalion launched its attack at 15:00 over the high, rugged terrain west of the "Horseshoe," as the deep curve in the Masan road was called, 4 miles (6.4 km) east of Komam-ni. Its mission was to seize and secure the high ground dominating the Horseshoe, and then relieve the pressure on the 24th Infantry's rear. Initially only one artillery piece was in position to support the attack. After the battalion advanced some distance, a North Korean force, estimated to number more than 1,000 men, counterattacked it and inflicted heavy casualties, which included 13 officers. Additional US tanks moved up to help secure the exposed right flank and rear, and air strikes helped to contain the North Korean force. The battalion finally succeeded in taking the high ground.

The next morning, September 4, instead of continuing the attack toward the 24th Infantry command post, 3rd Battalion, 27th Infantry was ordered to attack into the Komam-ni area where North Korean troops were fighting in the US artillery positions. This attack got under way at 09:00 in the face of heavy small arms fire. In the afternoon, heavy rains slowed the attack, but after an all-day battle, I and K Companies, with the help of numerous air strikes, captured the high ground dominating the Komam-ni crossroads. Numerous casualties in the battalion had led Kean to attach C Company, 65th Engineer Combat Battalion, to it. The next day, September 5, the 3rd Battalion, 27th Infantry turned its attack across rugged terrain toward Haman and drove through to the vicinity of the 24th Infantry command post. In its attack, the 3rd Battalion counted more than 300 North Korean dead in the area it traversed.

Artillery attacked

The series of events that caused Kean to change the direction of DeChow's attack toward Komam-ni began at 01:00, September 3. The 1st Battalion, 35th Infantry, protruded farther westward at this time than any other unit of the UN forces in Korea. Behind its positions on Sibidang-san the main supply route and rear areas were in North Korean hands, and only in daylight and under escort could vehicles travel the road. On Sibidang-san the battalion had held its original positions after the heavy fighting of September 1, completely surrounded by barbed wire, booby traps, and flares, with all supporting weapons inside its tight perimeters. The battalion had the advantage of calling for protective artillery fire covering all approaches. An hour after midnight a North Korean assault struck the battalion. The fight there continued until dawn September 3, when the 1st Battalion, 35th Infantry, counted 143 North Korean dead in front of its positions, and on that basis estimated that the total North Korean casualties must have been about 500 men. The 35th units also had the advantage of well-constructed strong points throughout the battle which the North Koreans could not penetrate.

In this night battle the 64th Field Artillery Battalion, supporting the 1st Battalion, became directly involved in the fighting. About 50 North Koreans infiltrated before dawn to A Battery's position and assaulted it. North Koreans employing submachine guns overran two artillery-machine-gun perimeter positions, penetrating to the artillery pieces at 03:00. There, Captain Andrew C. Anderson and his men fought hand-to-hand combat with the North Koreans. Some of the guns fell temporarily into North Korean hands but the artillerymen repulsed the attack, aided by the concentrations of fire from C Battery, 90th Field Artillery Battalion nearby, which cut off the North Koreans from reinforcements. In defending its guns in this night battle, A Battery lost seven men killed and 12 wounded.

Fighting in support of the Nam River front in the northern part of the 25th Division sector were five batteries of the 159th and 64th Field Artillery Battalions, firing 105 mm howitzers, and one battery of the 90th Field Artillery Battalion which fired 155 mm howitzers, for a total of 36 guns. One 155 mm howitzer fired from Komam-ni to the area north of Chungam-ni, the route for the NK 6th Division's supplies. Another forward artillery piece kept the Iryong-ni bridge over the Nam under fire. The 25th Division artillery estimated it killed approximately 1,825 North Korean soldiers during the first three days of September. In this critical time, the US Fifth Air Force added its firepower to that of the division artillery in support of the ground force. Walker attributed the UN victory in this sector directly to the extensive air support his division received in the battle.

North Koreans repulsed

Bitter, confused fighting continued behind the 35th Infantry's line for the next week. Battalions, companies, and platoons, cut off and isolated, fought independently of higher control and help except for airdrops which supplied many of them. Airdrops also supplied relief forces trying to reach the front-line units. Tanks and armored cars drove to the isolated units with supplies of food and ammunition and carried back critically wounded on the return trips. In general, the 35th Infantry fought in its original battle line positions, while at first one battalion, and later two battalions, of the 27th Infantry fought toward it through the estimated 3,000 North Koreans operating to its rear.

Although the 25th Division generally was under less pressure from North Korean units after September 5, there were still severe local attacks. On September 6, 1st Battalion, 27th Infantry, moved north from the Haman area to join 2nd Battalion in the cleanup of North Korean troops behind the 35th Infantry and below the Nam River. Caught between the 35th Infantry on its hill positions along the river and the attacking 27th Infantry units, large numbers of North Koreans were killed. Sixteen different groups reportedly were dispersed with heavy casualties during the day. By morning of September 7 there was clear evidence that survivors of the NK 7th Division were trying to escape across the Nam River. However the North Koreans launched another attack against the 35th Infantry, which it quickly repulsed. The 25th Infantry Division buried more than 2,000 North Korean dead, killed between September 1 and 7 behind its lines. This number did not include those killed in front of its positions.

Heavy rains caused the Nam and Naktong Rivers to rise on September 8 and 9, reducing the danger of new crossings. On September 8, after the 35th Infantry had been guarding it for a week, American F-82 Twin Mustangs mistakenly bombed the Namji-ri bridge over the Naktong and with one 500-pound (230 kg) bomb destroyed the 80 feet (24 m) center span. Only the bridges north of the junction of the Nam with the Naktong were supposed to be under aerial attack at this time. Some of the local commanders thought that had the North Koreans bypassed this bridge and crossed the Naktong farther east there would have been nothing between them and Pusan. However, North Korean attacks against 2nd Battalion, 35th Infantry occurred nightly. The approaches to the bridge on the north side were mined. At one time there were about 100 North Korean dead lying in that area. From September 9 to 16, there were limited attacks on the 35th Infantry's front but most of the North Koreans' momentum had been broken and they could not muster strong attacks against the regiment again.

North Korean withdrawal

See also: Battle of Inchon

The UN counterattack at Inchon collapsed the North Korean line and forced them back on all fronts. On September 16, however, 25th Infantry Division was still fighting North Korean forces behind its lines, and North Korean strong points existed on the heights of Battle Mountain, P'il-bong, and Sobuk-san. Kean felt that the division could advance along the roads toward Chinju only when the mountainous center of the division front was clear. He therefore believed that the key to the advance of the 25th Division lay in its center where the North Koreans held the heights and kept the 24th Infantry Regiment under daily attack. The 27th Infantry on the left and the 35th Infantry on the right, astride the roads between Chinju and Masan held their positions and could not advance until the situation in front of the 24th Infantry improved.

On September 19 the UN discovered the North Koreans had abandoned of Battle Mountain during the night, and the 1st Battalion, 24th Infantry, moved up and occupied it. On the right, the 35th Infantry began moving forward. There was only light resistance until it reached the high ground in front of Chungam-ni where hidden North Korean soldiers in spider holes shot at 1st Battalion soldiers from the rear. The next day the 1st Battalion captured Chungam-ni, and the 2nd Battalion captured the long ridge line running northwest from it to the Nam River. Meanwhile, the North Koreans still held strongly against the division left where the 27th Infantry had heavy fighting in trying to move forward.

The North Koreans withdrew from the Masan area the night of September 18–19. The NK 7th Division withdrew from south of the Nam River while the 6th Division sideslipped elements to cover the entire front. Covered by the 6th Division, the 7th had crossed to the north side of the Nam River by the morning of September 19. Then the NK 6th Division had withdrawn from its positions on Sobuk-san. The US units rapidly pursued them north, passing over the Battle Mountain positions, which were no longer of strategic importance.

Aftermath

The 35th Infantry suffered 154 killed, 381 wounded, and two missing during the battle. The 27th Infantry lost a total of 118 killed, 382 wounded, and one captured during the Battle of Pusan Perimeter, however this included five killed and 54 wounded at the Battle of the Bowling Alley and around 150 casualties at the First Battle of Naktong Bulge. In support of the Nam River operations, the 64th Field Artillery Battalion suffered 16 killed, 27 wounded, one captured and five missing, the 159th Field Artillery Battalion lost 18 killed and 41 wounded, and the 90th Field Artillery Battalion 15 killed, 54 wounded and one missing. The regiment had performed so well in repulsing the North Koreans that Kean nominated it for a Presidential Unit Citation.

The North Korean troops suffered heavily in the fight, most becoming casualties in the attack. By mid-September, the NK 7th Division was reduced to just 4,000 men, a loss of 6,000 from when it was committed to the perimeter. Only 2,000 from the NK 6th Division returned to North Korea, a loss of 80 percent of its strength. Large groups of troops from the divisions were captured as they attempted to return to North Korea, including up to 3,000 troops. The attacking force of over 20,000 had been reduced to only 6,000 by the end of the fights at Masan.

The fight at Masan remained a bitter stalemate during the entire six weeks of the Battle of Pusan Perimeter. Each side attempted several offensives on the other in an attempt to force a withdrawal, but the North Koreans were unable to pierce the UN perimeter, and the UN troops were unable to overwhelm the North Koreans to the point they were forced to withdraw. The battle itself was a tactical tie, since neither side could decisively defeat the other, however the UN units achieved their strategic goal of preventing the North Koreans from advancing further east and threatening Pusan. Instead, they were able to hold the line against repeated attacks until the Inchon attack, and were thus successful in defeating the North Korean army in subsequent engagements.