Eighth United States Army commander General James Van Fleet expected the PVA's next effort to come either in the west, as had the main force of the April attacks, or on his central front.

Judging the Uijongbu-Seoul, Bukhan River, and Chuncheon-Hongch'on corridors to be the most likely axes of enemy advance, he shifted forces by 4 May to place most of his strength and all US divisions in the western and central sectors and aligned the US I, IX and X Corps so that each was responsible for one of these avenues.

In further instructions for defense, Van Fleet ordered the No Name fortifications improved and directed IX Corps commander General William M. Hoge to give special attention to the Bukhan corridor, where the heaviest enemy buildup was reported.

Though the Topeka advance was off, Van Fleet ordered the 25th Canadian Infantry Brigade to move north, beginning on 15 May, to Kumnyangjang-ni, 25 miles (40 km) southeast of Seoul, and prepare to counter any enemy penetration in the Bukhan or Seoul-Suwon corridors.

[6]: 443–4 According to the consensus of current estimates of enemy dispositions as of 16 May, KPA I Corps on the west had spread forces eastward toward Route 33, taking over ground previously occupied by the PVA XIX Army Group.

His reason for shifting the main effort into the higher Taebaek Mountains despite the portended logistical problems may have been because the rugged ridges and sparse road net would reduce to some degree the UN Command's advantage of superior mobility, firepower and airpower.

Ruffner had manned the left and center of the division's 15 miles (24 km) sector south of Naep'yong-ni with the 9th and 38th Infantry Regiments and had reconstituted Task Force Zebra, the tank-infantry group that had performed well in late April, to occupy the line at the right.

The remainder of the Netherlands Battalion, under Coughlin's order, joined its forward company about 09:30, but, finding that Hill 1051 had fallen to the PVA, the Dutch commander, Lieutenant colonel William Eekhout, held up his advance while he targeted the height and the saddle beyond with artillery fire.

PVA killed or wounded by artillery fire on the saddle and the area below it marked the paths of the larger number veering east toward the front of Task Force Zebra and of the remainder heading down the valley toward the French.

Except for exchanging fire with Company F on the left flank, the PVA moving onto the front were inactive throughout the afternoon, but their number continued to grow as the Netherlands Battalion, though Coughlin on orders from Ruffner instructed it to attack at 13:00, failed to advance.

[6]: 451–2 In search of reserves to back up his hard-pressed central forces, Ruffner at mid-morning had asked Almond's permission to pull the two patrol base battalions of the 9th Infantry out of the left sector, which was obviously outside the zone of the PVA's main attack.

In immediate reinforcement he asked for a regimental combat team to help stabilize his right flank and for one heavy and two medium artillery battalions to increase long range fire on enemy concentration areas.

[6]: 453 Reinforcements ordered to the X Corps' sector by Van Fleet included the ROK 8th Division, which was to move north, initially to Chech'on, as soon as security battalions and National Police could take over its anti-guerrilla mission in southern Korea.

Geared for a move to the X Corps' sector since 11 May, the leading battalion of the 15th Regimental Combat Team made the 70 miles (110 km) trip from its assembly area southeast of Seoul to Hoengsong by midmorning on 17 May.

With an uncovered flank inviting envelopment by the PVA forces sweeping it on the east and its withdrawal route blocked by the 181st Division, the 23rd Infantry by daylight on 18 May was in a situation similar to that of ROK III Corps.

Though their commander, Eekhout, regained control quickly, Coughlin, at Ruffner's instruction, sent the battalion into an assembly near Hang'ye for rest and reorganization and stretched out the forces of Company A and F to man the vacated position.

The tanks churned in behind those of Company B, but under small arms, machine gun, and mortar fire ranging in from the west, panicky truck drivers drove helter-skelter into the hills beyond the stream bed.

Stragglers and abandoned communications equipment, weapons, and personal gear dotted the track of the two battalions as they made a tiring march under flanking fire from the west for part of the way and under drenching rainstorms that broke about 18:30.

Unable to turn around in the narrow road space between the embankment on the east and steep slopes on the west and faced with the danger of mines to the south, the tankers chose the nearly vertical 20 feet (6.1 m) drop on their left.

[6]: 459–60 The X Corps' line shaped by the withdrawals and shifts on 18 May amounted to a deep salient with the 3rd Battalion, 38th Infantry, at its apex in the Hill 800 complex and the 1st Marine Division presenting a solid face toward Chuncheon on its northwest shoulder.

Units regrouped by nightfall, a mix of three battalions of infantry from the 35th and 36th Regiments and a company of engineers, were clustered around the village of Hasolch'i (37°44′31″N 128°05′17″E / 37.742°N 128.088°E / 37.742; 128.088) located on a lateral mountain track 2 miles (3.2 km) south of Hill 683.

Of the 7th Division's other forces, about 700 had been corralled far to the south in Chech'on; another group had been found at the village of Soksa-ri (37°38′17″N 128°29′42″E / 37.638°N 128.495°E / 37.638; 128.495), located on Route 20 over 15 miles (24 km) southeast of P'ungam-ni in the ROK III Corps' sector.

[6]: 461 The new line of the 2nd Division, to be occupied on 19 May, cut Route 24 just below Han'gye on the west and reached across lateral ridges eastward, into what had become enemy territory, through Hill 683 to the village of Nuron-ni (37°45′50″N 128°09′50″E / 37.764°N 128.164°E / 37.764; 128.164), 3 miles (4.8 km) above P'ungam-ni.

Given the 15th Regimental Combat Team of the 3rd Division by Almond as a replacement for the 38th Infantry's going into Corps' reserve, Ruffner ordered the 15th initially to occupy the P'ungam-ni area as a preliminary to moving forward to the Nuron-ni sector of the line.

[6]: 462–3 The ROK III Corps' sector remained a scene of scattered forces throughout 19 May, troops trickling into collecting points along Route 20, some of both the 3rd and 9th Divisions taking up random positions about 5 miles (8.0 km) above the road.

In marked contrast, ROK I Corps all but completed an orderly withdrawal to Line Waco, both its divisions moving along the coast, the Capital in the lead and the 11th, though not in contact, prudently bounding south by regiment in bringing up the rear.

He thought such an attack would have a good chance of succeeding since intelligence indicated that only four PVA armies occupied the 40 miles (64 km) sector of the front west of Chuncheon and since Peng would need at least a week or ten days to shift any material part of his mass from the east to oppose the advance.

If for no other reason, he expected their logistical difficulties in the mountains to slow if not stop their advance within a matter of days; they would have created only a "long bag" that could be closed behind them by rapid drives to block their main routes of resupply and withdrawal.

At the division's left, large groups of PVA approaching the 23rd Infantry at a trot out of the Naech'on River valley about midday on 20 May wavered under mortar and artillery fire and air attacks and turned back before reaching the regiment's line.

To keep PVA/KPA forces from slipping out of the bottom of their long bag in the Hajinbu-ri area, Van Fleet late on 21 May directed ROK III Corps to make no further withdrawals and to restore defensive positions north of Route 20.