Once the 321st RCT was past this up-lift, and the Pocket which it bounded, it was to probe east in search of any routes east through the 600 yards necessary to reach the eastern edge of that portion of Peleliu. Any opportunities in that direction were to be exploited to encircle the Pocket on the north.
Behind the 321st RCT, the 5th Marines followed, pressed through, and attacked into northern Peleliu. Hanneken’s 7th Marines relieved the 1st, which was standing down to the eastern peninsula, also relieving the 5th Marines of their then-passive security role. The 5th was then tasked to capture northern Peleliu, and to seize Ngesebus-Kongauru.
This maneuver would involve the use of the West Road, first as a tactical route north, then as the line of communications for continued operations to the north. The road was comparatively “open” for a distance about halfway, 400 yards, to the northern limit of the Pocket, and paralleled by the ragged “cliff” which constituted the western shoulder of the up-lifted “plateau.” That feature was no level plateau, but a veritable moonscape of coral knobs, karst, and sinkholes. It had no defined ridges or pattern. The sinkholes varied from room-size to house-size, 10 to 30 feet in depth, and jungle- and vine-covered. The “plateau” was generally 30 to 100 feet above the plain of the road. Some 200–300 yards further to the east, it dropped precipitiously off into a sheer cliff, called the China Wall by those Marines who looked up to it from the southern and eastern approaches to the Pocket. To them, that wall was the western edge of the Pocket and the coral “plateau” was a virtually impassable shoulder of the Pocket.
ISOLATION OF UMURBROGOL
26, 27 SEPT
The plateau was totally impenetrable by vehicles. The coral sinkholes and uplifted knobs forced any infantry moving through to crawl, climb, or clamber down into successive small terrain compartments of rough and jagged surfaces. Evacuating any casualties would involve unavoidable rough handling of stretchers and their wounded passengers. The area was occupied and defended by scattered small units and individuals who did not sally forth, and who bitterly resisted movement into their moonscape. When Americans moved along the West Road, these Japanese ignored individuals, took under fire only groups or individuals which appeared to them to be rich targets.
The only tactical option along the West Road was to seize and hold the coral spires and cliffs commanding the road, and to defend such positions against infiltrators. Once those heights were seized, troop units and trucks could move along West Road. Until seized, the “cliff” offered concealment and some cover to occupying Japanese. Until those cliff positions were seized and held, the Japanese therein could be only temporarily silenced by heavy firepower. Until they were driven from their commanding positions, the road could not be treated as truly open.
Those terrain conditions existed for three-quarters of a mile along the West Road. There, abreast the north end of the Pocket, the plateau of coral sinkholes merged into a more systematic group of limestone ridges. These ridges trended slightly northeast, broadening the coastal strip to an east-west width of 200 to 400 yards.
Into that milieu, the 321st RCT was launched on 23 September, behind an hour-long intensive naval gunfire and artillery preparation against the high ground commanding the West Road. The initial Army reconnaissance patrols moved generally west of the road, somewhat screened from any Japanese still on the “cliff” just east of the road by vegetation and small terrain features. These tactics worked until larger units of the 2d Battalion, 321st, moved out astride the West Road. Then they experienced galling fire from the heights above the road.
The 321st’s 2d Battalion had relieved 3d Battalion, 1st Marines, along an east-west line across the road, and up onto the heights just above the road. Near that point, the 1st Marines had been tied into the forward left flank of 3d Battalion, 7th Marines. The orders for the advance called for 3/7 to follow behind the elements of 2/321, along the high ground as the soldiers seized the succeeding west edge of the cliff and advanced northward. However, the advanced elements along the ridge were immediately out-paced by the other 2/321 elements in the flat to their west. Instead of fighting north to seize the ridge, units responsible for that cliff abandoned it, side-stepping down to the road. They then advanced along the road, and soon reported that 3/7 was not keeping contact along the high ground.