South & SW Pacific Setting

🔗===================>> The WWII Japan > South & Southwest Pacific Submodule <<===============🔗
prior WWII Japan section: Japan Overreaches next WWII Japan sections: New Guinea Solomon Is.
South & Southwest Pacific subpages: South & SW Pacific Setting Securing Australia Isolating Rabaul
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WWII Hub

The WWII South & Southwest Pacific Areas - Geographic and Military Setting

In the desperate months of early 1942, US military planners split responsibility for operations in the corner of the Pacific Ocean shown on this map:

The South Pacific Area, under US Navy Department control, had an initial mission of preventing Japanese disruption of maritime traffic between the United States and Australia/New Zealand.
The Southwest Pacific Area, under US War Department control, had an initial mission of providing military support as Australia dealt with immediate Japanese threats from the north.

Political Changes Since WWII:

Papua New Guinea, also known as Papua or PNG, with capital of Port Moresby, achieved independence in 1975. Today's Papua includes the regions I refer to as SE New Guinea, NE New Guinea, Bougainville, and the Bismarck Archipelago.
Vanuatu was known as the New Hebrides during World War II.

Eastern Australia and Nearby Jurisdictioins

Australia, New Zealand, and Today's Nearby Jurisdictions

The Southwest Pacific Area (SWPA), US Army controlled, was commanded by General Douglas MacArthur, with initial SWPA headquarters in Brisbane, Australia.

MacArthur had been extracted from the Philippine Islands to Australia before Japanese forces completed their capture of the Philippines.
MacArthur initially lacked trained US troops and early land operations in the SWPA were primarily Australian in nature.
In April 1944, US forces assumed major combat operations in the SWPA.
Beginning in October 1944, US combat in the SWPA shifted to the Philippines, while Australian troops took over rear areas, where thousands of Japanese troops remained in pockets.
In mid 1945, Australia, with US support, began a series of invasions of the island of Borneo.

Southwest Pacific Area - 1942

The South Pacific Area (SPA), US Navy controlled, was commanded by Admiral William Halsey from 19 October 1942 to May 1944, with SPA headquarters at Noumea, New Caledonia. Halsey reported to Admiral Chester Nimitz at Pacific Area headquarters in Pearl Harbor, Hawaii.

Advance bases in the New Hebrides and subsequently in the Guadalcanal area supported South Pacific area combat.
When necessary, SWPA and SPA boundaries were fluid. In mid 1943, after the capture of Guadalcanal, South Pacific Area combat moved up the Solomon Island chain into ostensible Southwest Pacific Area territory.
Beginning in late November 1943 with the US invasion of the Gilbert Islands to the east of the Solomon Islands, the South Pacific Area began to fade in importance as the US Central Pacific Area campaign began.

South Pacific Area

South and Southwest Pacific Operations - Phase 1, Securing Australia

In early 1942, as Japanese forces moved with little effective opposition into the southern Pacific, concern grew that Australia might be blockaded, that Australia might come under sustained air or sea attack, or even that the Australian future might include a Japanese invasion such as China had experienced.

In May and June of 1942, Japan's sea-borne attempts to further advance the Japanese Empire boundaries were thwarted at the battles of the Coral Sea and Midway. Subsequently, Japan began smaller-scale advances in Papua in extreme southeastern New Guinea and in the Guadalcanal Island area in the southern Solomon Islands.

These small-scale Japanese offensives were thwarted in late 1942 and early 1943 by two parallel and lengthy Allied offensives, offensives that tied up increasing amounts of scarce Japanese resources.

In the southern Solomon Islands, by US forces driving the Japanese from the Guadalcanal area.
In Papua, Southeast New Guinea, by Australian and US forces pushing back the Japanese.

During this phase of Allied combat, US ground forces:

drove Japanese forces from Guadalcanal in the Solomon Islands.
participated with Australian forces in Papua, New Guinea operations culminating in the Battle of Buna-Gona.

This phase included vicious sea battles in and near the southern Solomon Islands, during which US naval deaths far exceeded those on the ground.

Securing Australia & Isolating Rabaul - Eastern New Guinea, Solomon Islands, & Bismarck Archipelago

South and Southwest Pacific Operations - Phase 2, Isolating Rabaul, April 1943-April 1944

By the beginning of February 1943, US and Australian and US advances in the Solomon Islands and New Guinea had removed the threat to Australian communications lines.

For the next fourteen months, Allied operations known collectively as Operation Cartwheel would focus on the neutralization of the main Japanese base at Rabaul, on the north edge of New Britain Island in the Bismarck Archipelago.

Japanese forces captured Rabaul early in 1942.

Rabaul was well-located with a suburb harbor and protected by multiple air fields.

Most ground combat during Phase 2 operations was handled by Australian forces in northeast New Guinea and US forces in the Solomon Islands and Bismarck Archipelago.

S & SW Pacific, Phase 2, The Operation Cartwheel Area

The key to isolating Rabaul was to develop a ring of secure Allied air bases within easy striking distance of Rabaul.

As Operation Cartwheel drew to a close in early 1944:

Marine Corps forces were withdrawn to use in the Central Pacific Campaign, which began earlier, in November 1943 with the invasion of the Gilbert Islands.
Australian forces were relieved from offensive operations to perform occupation duties and begin preparing for future landings in the Netherlands Indies.
MacArthur's Southwest Pacific Area forces began to leapfrog across the north coast of western New Guinea in preparation for the liberation of the Philippine Islands.

300-Mile Radius from Rabaul

Sources for Big Pigeon's WWII Japan > South & SW Pacific Hub and South & SW Pacific Settings webpages:

The South and Southwest Pacific Areas map is Map #15 from The War at Sea 1939-1945, Volume 3: The Offensive, Part I" and was found at https://archive.org/details/war-at-sea-1939-1945-vol-3-part-1. The full set of books follows, but it appears that they are mostly not on-line.

War at Sea 1939-1945, Volume 1: The Defensive, Roskill, S. W. London: HMSO, 1954
War at Sea 1939-1945, Volume 2: The Period of Balance, Roskill, S. W. London: HMSO, 1956
War at Sea 1939-1945, Volume 3: The Offensive, Part 1, Roskill, S. W. London: HMSO, 1960
War at Sea 1939-1945, Volume 3: The Offensive, Part 2, Roskill, S. W. London: HMSO, 1961

The 1942 - 1944 US Path Across the Southwest Pacific map is taken from google.com.
The Southwest Pacific Area - 1942 map - https://www.ibiblio.org/hyperwar/USA/USA-C-Papua/index.html.
The South Pacific Area map - https://www.ww2places.qld.gov.au/south-west-pacific-campaign#gallery-51274-17.
The New Guinea Area map is courtesy of history.army.mil.
I constructed the 300-Mile Radius from Rabaul map using www.calcmaps.com.
The Rabaul - Harbor & Airfields - WW II map - https://commons.wikimedia.org/wiki/File:Rabaul_-_map.jpg.