An average of 450 yards (410 m) separated four of these outposts, Detroit, Frisco, Seattle and Warsaw, which occupied hills lower than those on the left of the regimental line and therefore were more easily isolated and attacked.

As dusk settled over the battleground, Marine aircraft and artillery put down a smoke screen behind which the counterattack resumed, but the PVA succeeded in containing the two squads short of the crest.

As a result, while 3rd battalion reduced its frontage, the 1/7 Marines, under Lieutenant colonel Leo J. Dulacki, moved from the regimental reserve to take over the right-hand portion of the Jamestown Line.

Dulacki's Marines manned the main line of resistance from roughly 500 yards (460 m) southwest of the Hook to the boundary shared with the Commonwealth Division, including Outposts Warsaw and Verdun.

The 7th Marines completed its realignment just in time to meet a series of carefully planned and aggressively executed PVA attacks delivered on 6 and 7 October against five combat outposts and two points on the main line of resistance.

At 19:40 on the night of the 6th, an attacking company that had gained a foothold in the main trench on Detroit fell back after deadly fire stopped the PVA short of the bunkers.

Communications failed for a time, but at about 21:15 the defenders of Detroit requested variable-time fire for airbursts over the bunkers, which would protect the Marines while the PVA outside remained exposed to a hail of shell fragments.

The PVA renewed the attack just after midnight, and two Marine squads advanced from the main line of resistance to reinforce Frisco, only to be stopped short of their goal by fire from artillery and mortars.

During the final attack, Staff Sergeant Lewis G. Watkins, despite earlier wounds, took an automatic rifle from a more badly injured Marine and opened fire to keep the platoon moving forward.

[2]: 513–4 To keep Frisco firmly in Marine hands, however, would have invited attrition and ultimately required more men than Division commander General Edwin A. Pollock and Moore could spare from the main line of resistance.

During the 24 hours beginning at 18:00 on the 25th, PVA gunners scourged Moore's regiment with another 1,600 mortar and artillery shells, most of them exploding on the ground held by Dulacki's battalion.

The shelling abated briefly on the 25th but resumed, convincing the division's intelligence officer, Colonel Clarence A. Barninger, that the PVA was planning a major attack to overwhelm the Hook and gain control of the Samichon Valley.

[2]: 518–9 PVA troops stormed Ronson at 18:10 on 26 October after three days of preparatory fire that had collapsed trenches, shattered bunkers, and killed and wounded Marines at both outposts and on the Hook.

At Ronson, 50 or more PVA penetrated the defensive artillery concentrations, overran the position and killed or captured the members of the reinforced squad manning the outpost.

The thrust along the ridge that formed the spine of the Hook continued until the PVA encountered the observation post from which Second lieutenant Sherrod E. Skinner, Jr., was directing the fire of the 11th Marines.

The arrival of reinforcements enabled the members of Company C, scattered between the two perimeters, to form a blocking position on a ridge running east and west a few hundred yards to the rear of the Hook.

Anticipating commitment in this critical sector, the battalion commander, Lieutenant colonel Sidney J. Altman, had already drawn up a basic plan for such a counterattack and personally reconnoitered the area.

Tank gunners, mortar crews and artillerymen battered the recently captured Outpost Warsaw, other PVA troop concentrations, firing batteries, and supply routes.

The 1st Marine Air Wing also joined in, as F7F Tigercat night fighters used the ground-based AN/MPQ-2 radar to hit the main PVA supply route sustaining the attack, dropping their bombs less than 1 mile (1.6 km) west of the Hook.

Some 2 miles (3.2 km) west of the Hook, the battalion's three outposts at the Nevada Complex formed an arrowhead aimed at PVA lines, with Reno at the point, Carson on the left, and Vegas on the right.

The pattern of hostile activity opposite the 7th Marines earlier in October persuaded Pollock's intelligence specialists that the PVA had given first priority to seizing the Nevada Complex.

This estimate of PVA intentions caused the 11th Marines to plan concentrations in front of the 2nd Battalion, while Caputo set up strong ambush positions to protect the threatened outposts.

Although raked by fire from the front and rear, the PVA fought back, holding the Marines in check until they could break off the action and make an orderly withdrawal to the main line of resistance.

Within three hours, Company H stood ready to attack the PVA, whose bridgehead encompassed the Hook itself and a crescent of ridges and draws extending from the spine of that terrain feature and embracing a segment of the main line of resistance about 0.5 miles (0.80 km) wide.

A bullet struck O’Brien's armored vest, knocking him down, but he scrambled to his feet and continued toward the PVA, pausing only briefly to help a wounded man.

This headlong assault, which earned O’Brien the Medal of Honor, broke through the PVA perimeter and approached the PVA-held bunkers on the Hook before being contained by mortar and artillery fire.

The remainder of Company H widened the crack that O’Brien's platoon had opened and captured three prisoners as it overran the southeastern portion of the Hook before fierce shelling forced the advance elements to find cover and yield some of the ground they had taken.

The PVA reacted to the threat from I Company with artillery and mortar concentrations directed against not only the advancing Marines, but also Moore's command post and the weapons along the Jamestown Line that supported the assault.

The shelling battered not only the strongpoints immediately to the front of Company B, but also the PVA's supporting weapons and the routes of reinforcement and replenishment that passed through the PVA-held outposts of Warsaw and Ronson.

He believed that infantrymen should build and fight from individual positions with at least some overhead cover, rather than from large bunkers in which several defenders might be isolated and attacked with explosive charges or trapped if a direct hit collapsed the structure.