Garrisons were effectively besieged and denied shipments of food and medical supplies, and as a result, some researchers claim that 97% of Japanese deaths in this campaign were from non-combat causes.

[11] For the same reasons, General Douglas MacArthur, Supreme Commander Allied Forces South West Pacific Area, was determined to hold it.

The Japanese at Rabaul and other bases on New Britain would have easily overwhelmed any such effort (by mid-September, MacArthur's entire naval force under Vice Admiral Arthur S. Carpender consisted of 5 cruisers, 8 destroyers, 20 submarines, and 7 small craft).

Their operation plan decreed a five-pronged attack: one task force to establish a seaplane base at Tulagi in the lower Solomons, one to establish a seaplane base in the Louisiade Archipelago off the eastern tip of New Guinea, one of transports to land troops near Port Moresby, one with a light carrier to cover the landing, and one with two fleet carriers to sink the Allied forces sent in response.

[16] In the resulting 4–8 May 1942 Battle of the Coral Sea, the Allies suffered higher losses in ships but achieved a crucial strategic victory by turning the Japanese landing force back, thereby removing the threat to Port Moresby, at least for the time being.

[18] "[T]he Owen Stanley Range is a jagged, precipitous obstacle covered with tropical rainforest up to the pass at 6500-foot elevation, and with moss like a thick wet sponge up to the highest peaks, 13,000 feet above the sea.

The Japanese objective was to seize Port Moresby by an overland advance from the north coast, following the Kokoda Track over the mountains of the Owen Stanley Range, as part of a strategy to isolate Australia from the United States.

[24] A gradual improvement the numbers and skill of anti-aircraft gunners forced the Japanese bombers up to higher altitude, where they were less accurate, and then, in August, to raiding by night.

[28] "Thenceforth, the Battle of Milne Bay became an infantry struggle in the sopping jungle carried on mostly at night under pouring rain.

The Aussies were fighting mad, for they had found some of their captured fellows tied to trees and bayoneted to death, surmounted by the placard, 'It took them a long time to die'."

Thompson sub machine-guns jammed with the gritty mud and were unreliable in the humid atmosphere ... " The Japanese drive to conquer all of New Guinea had been decisively stopped.

Taking the airfield at Wau was a crucial step in this process, and to this end, the 51st Division was transferred from Indochina and placed under Imamura's Eighth Area Army at Rabaul; one regiment arrived at Lae in early January 1943.

"Within a few days, the enemy was retreating from the Wau Valley, where he had suffered a serious defeat, harassed all the way back to Mubo..."[37] About one week later, the Japanese completed their evacuation of Guadalcanal.

[38] General Imamura and his naval counterpart at Rabaul, Admiral Jinichi Kusaka, commander Southeast Area Fleet, resolved to reinforce their ground forces at Lae for one final all-out attempt against Wau.

If the transports succeeded in staying behind a weather front and were protected the whole way by fighters from the various airfields surrounding the Bismarck Sea, they might make it to Lae with an acceptable level of loss, i.e., at worst half the task force would be sunk en route.

[39] It is indicative of the extent to which Japanese ambitions had fallen at this point in the war that a 50% loss of ground troops aboard ship was considered acceptable.

Most important of all, the bombers of MacArthur's air forces, under the command of Lieutenant General George C. Kenney, had been modified to enable new offensive tactics.

The noses of several Douglas A-20 Havoc light bombers had been refitted with eight 50-caliber machine guns for strafing slow-moving ships.

[40] About 6,900 troops aboard eight transports, escorted by eight destroyers, departed Rabaul at midnight 28 February under the command of Rear Admiral Masatomi Kimura.

"[43] Admiral Isoroku Yamamoto promised the emperor that he would pay back the Allies for the disaster at the Bismarck Sea with a series of massive airstrikes.

To demonstrate the seriousness of the effort to the Supreme War Council, multiple shifts of high-ranking personnel were also effected: both Yamamoto and Ozawa moved their headquarters to Rabaul; and Eighth Fleet commander Vice Admiral Gunichi Mikawa as well as General Imamura's chief of staff were sent to Tokyo with advice and explanations for the respective General Staffs (Vice Admiral Tomoshige Samejima replaced Mikawa as Eighth Fleet commander).

[citation needed] In order to reduce and capture the vast Japanese naval and air facilities at Rabaul, two major moves were planned for the end of June: Eventually, the Joint Chiefs of Staff realized that a landing and siege of "Fortress Rabaul" would be far too costly and that the Allies' ultimate strategic purposes could be achieved by simply neutralizing and bypassing it.

At the Quebec Conference in August 1943, the leaders of the Allied nations agreed to this change in strategy focusing on neutralizing Rabaul rather than capturing it.

[50] Despite the disaster of the Bismarck Sea, the Japanese could not give up on recapturing Wau, and they kept significant resources in the territory of Papua, on north shore of the eastern end New Guinea.