After being pushed back northward by the UN's Operation Thunderbolt counteroffensive, the PVA was victorious in this battle, inflicting heavy casualties on the UN forces in the two days of fighting and temporarily regaining the initiative.

When the U.S. armored and artillery forces supporting the ROK 8th Division found their infantry screen evaporating, they began to withdraw down the single road through the twisting valley north of Hoengsong; but they were soon outflanked by PVA infiltrating cross-country.

Colonel Robert G. Fergusson, the acting intelligence officer who prepared the estimate, told Ridgway that the long lull was purely the consequence of Chinese resupply, transportation and reinforcement difficulties.

Some of the 198th Division forces who had swept around the 21st Regiment meanwhile raced down both sides of Route 29, bypassed the American position at Ch'angbong-ni, and blocked the road near a bridge 3 miles (4.8 km) farther south.

But after the Chinese engineered the collapse of the ROK 8th Division, Corps' control inhibited the American commanders of support forces and of units on the line of departure in reacting rapidly.

[3]: 268 In one instance, Captain Sherman D. Jones, the commander of Support Team A, scorned any need to get permission to withdraw and fought east over the blocked mountain road toward the 3rd Battalion, 38th Infantry.

[3]: 269 A group of about 300 soldiers of the 197th, thrust southwest toward Ch'angbong-ni during the attack and around 02:30 on the 12th hit Company A, 38th Infantry, holding the northeast sector of Support Force 21's perimeter.

Almond was under the impression, however, perhaps because of the several hands through which Keith's request had passed, that Support Force 21 would withdraw to Hoengsong, not just to a position near the 3rd Battalion, 38th Infantry.

Machine gunfire from the left kept Mace from getting back inside, and a grenade, apparently thrown from the ditch on the east side of the road, then blew him off the tank, although without wounding him.

To the rear, following the same westward drift to escape fire coming in from the left of the road, Mace, the two infantry squads, and a number of South Koreans took cover in the ground on the right.

[3]: 270 Behind the scattered tank-infantry team, Keith's main column received heavy small arms and machine-gun fire from the heights east of Route 29 while it formed and stretched out on the road below the support force perimeter.

As the company prepared to move, the commander, 1st Lieutenant George W. Gardner, saw three 155-mm howitzers attached to their M5 tractors, a full ammunition truck and several jeeps and trailers, all unattached, in a roadside paddy southwest of his position.

Gardner found the fifth howitzer on the road where Mace's two tanks had been knocked out and where the main body of the support force also had come under heavy mortar and machine gunfire.

But the assault regiments ran into hard counterattacks by the Korean People's Army (KPA) V Corps, which now appeared to be joining the advance on Hoengsong, and by early afternoon were withdrawing to escape being enveloped.

He notified Corps headquarters that he would move due east to the Twinnan-mul River, which flowed southwest past the northern edge of Hoengsong, then follow a primitive road through the Twinnanmul valley.

Mortar and artillery fire and airstrikes arranged by Coughlin pounded the ridges ahead of the support force, but Keleher's men almost immediately ran into strong resistance and lost momentum after 1 mile (1.6 km).

About the time Keleher's attack stalled, word reached Coughlin that the 18th Regiment, ROK 3rd Division, assembled about 3 miles (4.8 km) east of Hoengsong, would send a battalion north astride Route 29 at 14:00 to help open the road.

The assistant commander of the ROK 3rd Division was to head the force, but Almond assigned the Corps armored officer, Lieutenant colonel Jack F. Wilhm, to coordinate the organization and opening of the infantry-armor advance.

A little after 18:00 Wilhm, the Corps' armored officer, came into the 38th Infantry command post to notify Coughlin to take charge of all American troops in the Hoengsong area.

[3]: 275–6 The ROK 3rd and 5th Divisions, the latter being followed by forces of the KPA V Corps, meanwhile were passing south through the area east of Hoengsong en route to their newly assigned defense line.

Although the cut was beyond the support force assembly, Baker began to pull the leading troops and trucks back into Hoengsong and reassemble them along Route 29 south of town.

Suffering moderate casualties and losing one tank, Support Team E had fought forward for about 1.5 miles (2.4 km) and joined Coughlin's forces coming south around 21:00.

After the E team tanks turned around and took the lead, the combined force, though still receiving heavy fire from left and right and still obliged to attack PVA positions bordering the road, was able to move south at a steady pace.

[3]: 276–7 Coughlin intended that the forces coming in from the north continue through Hoengsong, reorganize in an assembly area 3 miles (4.8 km) south of town, then proceed to the new defense line at Wonju.

Part of the artillery reached Wonju without further trouble, but as this segment passed a point about 1.5 miles (2.4 km) below Hoengsong, PVA forces crowded in on the road from the west and opened fire.

Baker, bringing up infantry and some of Coughlin's tanks from the rear, attacked and destroyed the PVA position, allowing the support force to move on to Wonju with no further encounter.

The occupants of the truck were either killed or scattered, and an alert PVA machine gunner opened sustained fire on the cab to prevent anyone from trying to reach and restart the vehicle.

On the following day, he instructed his inspector-general to investigate all "the circumstances attending the loss by X Corps of artillery pieces and other major items of equipment on or about 12 February 1951."

Without being specific, but referring to Support Force 21, he told Ridgway that "in only one instance, now under investigation, have I found loss of U.S. equipment due to faulty leadership, and all the facts on this are not evident yet."

Recalling Ridgway's earlier concern for Roundup control arrangements, Almond assured him that "the operation, as conceived and coordinated, included the protection of the U.S. artillery units involved and was, in my opinion, all that could be desired.