Then, on the evening of 10 June, the artillery fire became intense and the PVA followed up with coordinated attacks ranging from a battalion to a regiment in strength on the sector held by the ROK 5th Division.

Smashing through the outposts, the PVA seized Hills 973 and 882, 10 miles (16 km) northwest of Heartbreak Ridge and part of the main line of resistance.

PVA units swiftly moved to the offensive again and forced the ROK troops to pull back 1,000 meters south of Hill 973.

Heavy artillery, mortar, and small arms fire, coupled with the PVA's willingness to reinforce his units and counterattack the ROK assault forces, prevented the UNC troops from recouping their terrain losses.

When the PVA showed that they intended to retain possession of Hills 973 and 882, which were located on the main ridge leading to Hill 1220 from the west, the X Corps commander, Lieutenant general Isaac D. White, moved up the ROK 7th Infantry Division, the Corps' reserve, and placed it on the left flank of the ROK 20th Division.

X Corps immediately made efforts to speed supplies and equipment forward to the ROK 5th Division and to replace its personnel losses.

Since lateral roads were scarce, twelve H-19 helicopters were allocated to help out and they lifted a quarter of a million pounds of material forward to the front.

Two PVA companies penetrated the main line positions of the ROK 16th Regiment, 8th Division, southeast of Finger Ridge, but did not attempt to follow up the breakthrough.

Heavy artillery and mortar fire accompanied the attacks and the PVA pressed on vigorously despite a staunch defense by both ROK divisions.

The PVA held the hill with a small force and permitted the ROK troops to move in, then directed heavy artillery and mortar fire on the area and counterattacked in mass.

To bolster the rear areas and the security of the prisoner of war camps, in late June the UNC commander General Mark W. Clark ordered the 24th Infantry Division to prepare for a temporary move from Japan to Korea.

Reports of troop movements, heavy traffic and stockpiling behind PVA/KPA lines alerted all commanders that they were preparing to strike again in force.

PVA counter-reconnaissance screens made it difficult to ascertain how much strength the Chinese were massing, but the concentrations were greatest on the central front around Kumsong.

The PVA drew back on 8 July to regroup, but that night they returned in the wake of 6,500 rounds of artillery and mortar fire, and won possession of the north slope of one of the ridges.

[10] By evening of 13 July the PVA had moved elements of five armies into attack and support positions along the central sector that encompassed the Kumsong salient.

The increase in the tempo of artillery and mortar fire on 13 July corroborated earlier intelligence reports from prisoners, deserters, agents and reconnaissance that the PVA were about to launch a major drive aimed primarily at ROK units on the central front.

In the Sniper Ridge sector, long a bone of contention, ROK forces had to pull back to avoid being cut off.

Battalion and two-battalion attacks accompanied by heavy artillery and mortar support broke through the ROK 3rd Division's outpost system and drove into the main line positions.

Lateral and front-to-rear lines of communications were soon out of commission and radio and foot messengers became the chief means of sending and receiving instructions and information.

Reports trickling in from the front were often delayed and usually incomplete as the ROK commanders displayed their customary unwillingness to forward unfavorable news that would cause them to lose face.

Eighth Army commander General Maxwell D. Taylor therefore, on 14 July ordered the ROK Capital, 6th, 8th, 3rd and 5th Divisions to fall back south of the Kumsong River line at the base of the bulge.

In the process of complying with Taylor's instructions however, the ROK commanders lost contact with and control of some of their units, with the result that many of them did not stop at the Kumsong line.

The intensity and determination of the Chinese offensive impressed Generals Clark and Taylor to the point that they decided to fly reinforcements from Japan to Korea to bolster the front.

The U.S. 187th Airborne Regimental Combat Team (187th RCT) was rushed to Korea and on 14 July Taylor attached the unit to the U.S. 2nd Infantry Division.

The PVA offensive had slowed by this time and the Chinese were organizing the defense of the terrain they had taken and replacing the heavy casualties they had suffered in breaking through the ROK positions.

Efforts to cross the river and take defensive positions on the north bank of the Kumsong met with increasing PVA resistance and were abandoned after 20 July.

[9]: 476 For the last week of the war the ROK II Corps held the Kumsong River line against minor PVA pressure.

While ROK II Corps was carrying out its counteroffensive, the PVA/KPA exerted pressure upon several scattered points along the Eighth Army line in an effort to take long-contested hills and outposts prior to the signing of an armistice.

The reasons behind this pressure were difficult to fathom, since all of the threatened points fell in the demilitarized zone and would have to be abandoned by the UNC forces anyway.

[9]: 477 The 2020 film The Sacrifice is set during the Battle of Kumsong and tells the story of a bridge that the Chinese People's Volunteer Army must defend in order to reinforce the frontline while the United States Air Force and artillery attempt to halt the crossing.