WWII - Japan

Naval War

 bigpigeon.us webpage WWII - Japan > South & SW Pacific, updated by RAC 16 May 2022.

In early 1942, as Japanese forces moved with little effective opposition into the southern Pacific, concern grew that lines of commerce between North America and Australia might be broken, that Australia might come under attack, or even that the Australian future might include a Japanese invasion.

In ground combat, the Japanese offensive was blunted by parallel Allied operations:

• In Southeast New Guinea, by Australian forces, with US support, pushing back the Japanese.
• In the southern Solomon Islands, by US forces driving the Japanese from Guadalcanal Island.

Major US land combat in the South and Southwest Pacific Theaters:

• began in August 1942 with the US Navy supported 1st Marine Division invasion of Guadalcanal in the Solomon Islands.
• ​ended with the US Army's September 1944 invasion of Morotai in the Dutch Indies, 2,300 miles to the northwest. 

1942-1944 US Path Across the Southwest Pacific

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Links to South Pacific Area (SPA) & Southwest Pacific Area (SWPA) subordinate webpages: 

• The Solomons Naval War - SPA
• The Solomon Islands - Guadalcanal (Aug 1942 - Feb 1943) - SPA
• Southeast New Guinea - Papua  (Jul 1942 - Jan 1943) - SWPA
• Northeast New Guinea - Lae to Madang (Apr 1943 - Apr 1944) - SWPA
• The Solomon Islands - New Georgia (Jun - Aug 1943) - SPA
• The Solomon Islands - Bougainville (Nov 1943 - Mar 1944) - SPA/SWPA
• The Bismarck Archipelago  (Dec 1943 - Apr 1944) - SWPA
• Western New Guinea (Apr 1944 - Sep 1944) - SWPA

• The Southwest Pacific Area (SWPA), US Army controlled, was commanded by General Douglas MacArthur, with headquarters in Brisbane, Australia.
• The South Pacific Area (SPA), US Navy controlled, was commanded by Admiral William Halsey from 19 October 1942 to May 1944 , with headquarters in Noumea, New Caledonia.

In the above list of links, I have indicated, where appropriate, which command was in charge.

Southwest Pacific Area - 1942

South Pacific Area

I viiew the complex Allied ground offensive in the South and Southwest Pacific from 1942 through 1944 as consisting of three chronological phases, each with a different goal:

Phase 1, protecting Australia, July 1942 – February 1943. The main US ground contributions were:

• participating with Australian forces in the Battle of Buna-Gona in Papua, New Guinea
  
• driving Japanese forces from Guadalcanal in the Solomon Islands.

S & SW Pacific, Phases 1 & 2 - Eastern New Guinea, Solomon Islands, & Bismarck Archipelago

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Phase 2, isolating the main Japanese base at Rabaul

Rabaul is located in the Bismarck Archipelago, on the north end of New Britain Island. The reduction of Rabaul, known as Operation Cartwheel, officially began in April 1943 and ended in April 1944.

Rabaul was well-located with a suburb harbor and protected by multiple air fields. The key to isolating Rabaul was to develop a ring of secure Allied air bases within easy striking distance of Rabaul.
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Australian forces performed most Phase 2 ground combat on New Guinea, while the US handling most combat in the Bismarck Archipelago and the Solomon Islands. 

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

300-Mile Radius from Rabaul

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Phase 3, advancing westward in New Guinea towards the Philippines, ending at Morotai in the Dutch Indies. Phase 3 occupied MacArthur’s Southwest Pacific Theater forces from April to September 1944. (landings shown on the accompanying map)

While Phase 1 and Phase 2 operations involved both US Army and Marine Corps ground troops, Phase 3 used only Army ground forces. Marine Corps forces were withdrawn from the South Pacific to use in the Central Pacific Campaign, which began in November 1943 with the invasion of the Gilbert Islands.

S & SW Pacific, Phase 3 - Western New Guinea

​Sources for the South/Southwest Pacific webpage:

• 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.