At the end of the action-filled day, the Marines were stalled. In the morning of 26 November surprised scouts found that the Japanese had pulled out in the darkness. Now all of the wet, smelly, churned-up terrain around the Piva Forks, including the strategic ridgeline blocking the East-West Trail, was in Marine hands.
There now occurred a shuffling of units which resulted in the following line-up: 148th and 129th Infantry Regiments on line in the 37th Division sector on the left of the perimeter. 9th Marines, 21st Marines, and 3d Marines, running from left to right, in the Marine sector.
The Koiari Raid
As a kind of final security measure, IMAC was concerned about a last ridge of hills, some 2,000 yards to the front, and really still dominating too much of the perimeter. Accordingly, on 28 November, General Geiger ordered an advance to reach Inland Defense Line Fox. As a preliminary, to protect this general advance from a surprise Japanese attack on the far right flank, a raid was planned to detect any enemy troop movements, destroy their supplies, and disrupt their communications at a place called Koiari, 10 miles down the coast from Cape Torokina. The 1st Parachute Battalion, just in from Vella Levella under Major Richard Fagan, drew the assignment, with a company of the 3d Raider Battalion attached. While it had never made a jump in combat, the parachute battalion had been seasoned in the Guadalcanal campaign.
Carried by a U.S. Navy landing craft, the men in the raid were put ashore at 0400, 29 November, almost in the middle of a Japanese supply dump. Total surprise all around! The Marines hastily dug in, while the enemy responded quickly with a “furious hail” of mortar fire, meanwhile lashing the beachhead with machine gun and rifle fire. Then came the Japanese attacks, and Marine casualties mounted “alarmingly.” They would have been worse except for a protective curtain of fire from the 155mm guns of the 3d Defense Battalion back at Cape Torokina. With an estimated 1,200 enemy pressing in on the Marines, it was painfully clear that the raiding group faced disaster. Two attempts to extricate them by their landing craft were halted by heavy Japanese artillery fire. Now the Marines had their backs to the sea and were almost out of ammunition. Then, about 1800, three U.S. destroyers raced in close to the beach, firing all guns. They had come in response to a frantic radio signal from IMAC, where the group’s perilous situation was well understood. Now a wall of shell fire from the destroyers and the 155s allowed two rescue craft to dash for the beach and lift off the raiding group safely. With none of the original objectives achieved, the raid had been a costly failure, even though it had left at least 145 Japanese dead.
Hellzapoppin Ridge
Now the action shifted to the final targets of the 3d Marine Division: that mass of hills 2,000 yards away. Once captured, they would block the East-West Trail where it crossed the Torokina River, and they would greatly strengthen the Final Inland Defense Line that was the Marines’ ultimate objective. A supply base, called Evansville, was built up for the attack in the rear of Hill 600 for the forthcoming attacks.
The 1st Marine Parachute Regiment, under Lieutenant Colonel Robert H. Williams, was informed, two days after its arrival on Bougainville, that General Turnage had assigned it to occupy those hills which IMAC felt still dominated much of the Marine ground. That ridgeline included Hill 1000 with its spur soon to be called Hellzapoppin Ridge (named after “Hellzapoppin,” a long-running Broadway show), Hill 600, and Hill 600A. To take the terrain Williams got the support of elements of the 3d, 9th, and 21st Marines (which had established on 27 November its own independent outpost on Hill 600). By 5 December, the 1st Parachute Regiment had won a general outpost line that stretched from Hill 1000 to the junction of the East-West Trail and the Torokina River.