Planning the Operation

LtGen Alexander A. Vandegrift was an early commander of IMAC. Department of Defense Photo (USMC) 61899

This kind of strong enemy reaction, in the air and at sea, had been expected by American staff officers who had put in long weeks planning the Bougainville operation. Looking at a map of the Solomon Islands chain, it was obvious that this largest island (130 by 30 miles) on the northwest end was a prime objective to cap the long and painful progress northward from the springboard of Guadalcanal at the south end. As Guadalcanal had been the beginning of the island chain, so now Bougainville would mark the top of the ladder in the Northern Solomons. From Bougainville air fields, American planes could neutralize the crucial Japanese base of Rabaul less than 250 miles away on New Britain. From Bougainville, the enemy could defend his massive air-naval complex at Rabaul. "Viewed from either camp, the island was a priority possession."

There were the usual sequences of high level planning conferences, but, on 1 October 1943, Admiral William F. Halsey, Commander, South Pacific Area, notified General Douglas MacArthur, Supreme Allied Commander, Southwest Pacific Area, that the beaches on Empress Augusta Bay in the middle of Bougainville's west coast would be the main objective. This location was selected as the point to strike because with the main Japanese forces 25 miles away at the opposite north and south ends of the island, it would be the point of least opposition. In addition, it provided a natural defensive region once the Marines had landed and their airfields had been gouged out of the swamp and jungle. Finally, the target area would provide a site for a long-range radar installation and an advanced naval base for PT (patrol torpedo) boats.

It promised to be a campaign in a miserable location. And it was. There were centipedes three fingers wide, butterflies as big as little birds, thick and nearly impenetrable jungles, bottomless man grove swamps, crocodile infested rivers, millions of insects, and heavy daily torrents of rain with enervating humidity.

Major General Allen H. Turnage, the 3d Marine Division commander, summarized these horrors. "Never had men in the Marine Corps had to fight and maintain themselves over such difficult terrain as was encountered on Bougainville."

To carry out this operation, Lieutenant General Alexander A. Vandegrift, Commanding General, I Marine Amphibious Corps (IMAC),* had in his command for the operation:

3d Marine Division
1st Marine Parachute Regiment
2d Marine Raider Regiment
37th Infantry Division, USA (in reserve)

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* Gen Vandegrift, 1st Marine Division commander on Guadalcanal, relieved MajGen Clayton B. Vogel as IMAC commander in July 1943. He in turn was relieved as IMAC commander by MajGen Charles D. Barrett on 27 September. Gen Vandegrift was on his way home to Washington to become 18th Commandant of the Marine Corps when, on the sudden death of Gen Barrett on 8 October, he was recalled to the Pacific to resume command of IMAC and lead it in the Bougainville operation. He, in turn, was relieved by MajGen Roy S. Geiger on 9 November.

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LtGen Haruyoshi Hyakutake, commanded the Japanese forces on Bougainville. Photo courtesy of Cyril J. O'Brien

The Marine riflemen in these units were supplemented by a wide range of support: 155mm artillery; motor transport; amphibian tractor; and signal, medical, special weapons, Seabee, and tank battalions. The 3d Division had its own engineers and pioneers in the 19th Marines and artillery in the 12th Marines.

Immediately following Vandegrift's operation order, practice landing exercises were conducted in the New Hebrides and on Guadalcanal and Florida Islands.

The objectives assigned on Bougainville were to seize a substantial beachhead and build airstrips. Then American planes could assure final neutralization of the Japanese airfields at Kahili, Buka, and Bonis airfields at the north and south ends of Bougainville. (By 31 October, American planes had initially rendered the Japanese fields inoperable.) After that would come a massive increase in air operations against Rabaul.

Facing the invading Marines was a formidable enemy force dispersed on the island. At Buin, for instance, there were 21,800 Japanese. Responsible for the defense was an old adversary, Lieutenant General Haruyoshi Hyakutake, commander of the Seventeenth Army, and the man the Marines had defeated at Guadalcanal. His main force was the 6th Division.

Working with the ground U. S. forces were the aviators of Air Solomons: New Zealand fighters, Army Air Force bombers, and the 1st and 2d Marine Aircraft Wings. As early as 15 August fighter planes from VMF-214 (the famous Black Sheep squadron) had strafed the Kahili airfield at the southern end of Bougainville. Now, in October, there were repeated strikes against the Japanese planes at other Bougainville airfields.

At sea, Halsey had designated Rear Admiral Theodore S. Wilkinson as commander of Task Force 31. Under him were Rear Admiral Frederick C. Sherman with the carriers (TF 38) and Rear Admiral Aaron S. "Tip" Merrill with the cruisers and destroyers (TF 39). Their job was to soften up the defenders before the landing and to safeguard the Marine-held beachhead.