New Guinea Forces
The main aim of the southern operations at the outbreak of the Greater East Asian War was to secure the natural
resources of the Netherlands East Indies.1 This involved 
mounting surprise attacks on British Malaya and the
US-occupied Philippines, and using these areas as a stepping stone for an early invasion of the Netherlands
East Indies. In addition to securing areas of natural resources, the idea was to construct a “line of defence”
along the Sunda Island archipelago.
If the event that the Japanese attacked Malaya and the Netherlands East Indies, the US Pacific Fleet had
planned to curb the Japanese advance by undertaking attacks in the Marshall Islands area, by disrupting sea
transport routes, and by conducting air raids on strategic areas. In addition, the US had decided to provide
support to Allied nations to mount defensive operations in Malaya and the Netherlands East Indies areas.2
Meanwhile, the Japanese Combined Fleet prepared for operations based on the fundemental policy of
destroying the US Pacific Fleet in the waters of the inner south Pacific islands. While Palau, Saipan, Truk, and
elsewhere were raised as bases for this purpose, Truk was considered the most imortant base.
Imperial General Headquarters incorporated the invasion of the Bismarck Archipelago in the south Pacific into
the sphere of strategic plans, which were developed in November 1941.3 This was based in the notion that Truk
would not be safe while Rabaul remained in Allied hands.
The Japanese forces offensive operations, which began at the outbreak of the war with the surprise attack on
Pearl Harbor, had progressed fairly smoothly in all theatres of operation. Consequently, the army and navy
cooperated in late January 1942 to invade Rabaul and key surrounding areas. The army committed the South
Seas Force, an infantry group based on three battalions, to these operations.
Thereafter, naval landing troops, acting in concert with army infantry companies, advanced into strategic
locations at Lae and Salamaua in eastern New Guinea, and on Bougainville in the Solomon islands. In May,
naval units occupied the island of Guadalcanal, and Tulagi on Florida Island.
At that time, Imperial Headquarters had completed attacks on key areas in the southern region. Recognising
that the main base for Allied counter-attacks would be the Australian mainland, Imperial Headquarters planned
a blockade operation to isolate Australia from the US. This would involve attacks on the islands of Samoa, Fiji,
and New Caledonia, the main air and sea relay bases between Hawaii and the Australian mainland. The army
formed the 17th Army (based on 12 infantry battalions), and the navy the 8th Fleet, in response to the
requirements of this operation.
Meanwhile, after many twists and turns, the decision was ultimately made to attempt an overland attack against
Port Moresby, on the south coast of New Guinea, through the Owen Stanley Range. The South Seas Force,
which had undertaken the attack against Rabaul, was appointed to the task. The advance party landed at Buna
in July 1942, with the main strength of the force landing in mid-August. The advance on Port Moresby began,
with troops carrying 16 days of supplies on their backs.7 Imperial Headquarters had judged that the Allied
counter-offensive in the South Pacific would not commence until after the start of 1943, so they were
cautiously investigating operations in the Indian Ocean and against Chungking.8 However, preparations for
Allied counter-offensives in the South Pacific had proceeded much more quickly that Japanese planners
anticipated.
A fleet of seven warships began shelling Lunga Bay on Guadalcanal at 4.13 pm on 7 August 1942. The Allied
counter-offensive in the Solomon islands, with an eye on the ultimate prize of Rabaul, had now begun.9 The
naval units on Guadalcanal and Tulagi, who were responsible for establishing an airfield and a seaplane base,
were no match for the full-scale Allied counter-offensive.
There was little true appreciation that this was the beginning of the Allied counter-attack.
The Ichiki Detachment (based on one infantry battalion), which was heading to Ujina from Guam, was hastily
despatched. The detachment landed on Guadalcanal on 18 August and began its attack during the night of 20
August. Following that, the Kawaguchi Detachment (four infantry battalions) was quickly dispatched from
Palau, landing on Guadalcanal between 30 August and 7 September. Attacks were then made during the nights
of 12 and 13 September. The attacks of both the Ichiki and Kawaguchi Detachments, however, ended in
failure.10 During this time, fierce air and sea battles raged around the island. These battles had a significant
flow-on effect for the land battles by both detachments.
Since the start of the war on 8 December the previous year, army units had virtually swept all before them
across a range of battlefields. The reality of defeat and failure, however, sent a shock wave across all theatres of
operation. How could this situation be handled, and what was the reaction going to be? This was a major
headache, even one that raised wider war leadership issues.
The result of the battles on Guadalcanal also had an impact on the South Seas Force, which was at that time
thrusting towards Port Moresby in New Guinea. The force commander, on 14 September, made the
determination based on orders from the army to begin a difficult withdrawal operation.11
Imperial Headquarters and local army commanders all felt that if Guadalcanal could be retaken, then the
situation in the South Pacific could be salvaged. Full-scale preparations were consequently undertaken in late
September 1942.
Meanwhile, fierce battles were being fought in Europe between German and Soviet armies within the great
curve of the Don River and at Stalingrad. On the Chinese mainland, thorough successes along the entire
Zhejiang–Jiangxi line encouraged discreet preparations for No. 5 Operation against Chungking.*
Click here to download Japanese Army Operations in the South Pacific Area by Steven Bullard
Source
Australian War Memorial: Australian Japanese Research Project