Author: Hiroyuki Shindo
From February 1942 until July 1944, a war of attrition was fought by the air forces of the United States, Australia and Japan in Papua, New Guinea, the Bismarck Archipelago and the Solomon Islands. Although this period comprises more than half the length of the war in the Pacific, somehow more attention seems to be paid in popular histories to other aspects of that war, such as the actions of the carrier fleets of Japan and the United States. The air campaign in the South Pacific, however, was of extreme importance, not just to the persons of all sides who fought there, but to the outcome of the war. This is because it was in, over and around the island of New Guinea that the Japanese Army and Navy, and their air forces, were first stopped, worn down and finally pushed back. Since it is obviously impossible to look at every aspect of that campaign in a single article, the following discussion concentrates on the major strategic and operational issues on the Japanese side. It also focuses on Japanese air operations over the main island of New Guinea, even though in actuality these operations, when seen from the Japanese side, were closely intertwined with activities undertaken in the Solomon Islands.
Broadly speaking, the Japanese air campaign over New Guinea may be divided into four phases. The first phase was the Japanese Navy’s offensive campaign against Port Moresby, from the spring through fall of 1942. Next, from early 1943 until about June of that year, the Japanese Army filled in for the Navy (whose air forces were increasingly committed to the Solomons campaign) and fought a campaign which was intended to be offensive but became increasingly defensive in nature. The third phase was a short period in the summer of 1943 in which the Japanese Army assigned a more positive role to its air forces in New Guinea, only to see the bulk of that force destroyed in a single air attack. Finally, the Japanese Army air forces fought an unglamorous defensive campaign for approximately a year, from the summer of 1943, before the Japanese Army was pushed out of New Guinea and the war itself shifted to the Marianas and the Philippines.
Occupation of Rabaul and the start of air operations against Port Moresby
When the Japanese Army and Navy developed plans for a forthcoming war with the United States and Great Britain in 1941, the islands of the Bismarck Archipelago, particularly New Britain, were included in their target list from early on. This was because Japanese planners (especially those in the Navy) saw Rabaul on New Britain, with its excellent natural harbour, as a potential threat to Truk Island in the Carolines. Situated only 1100 kilometres from Rabaul, Truk was the site of the Japanese Navy’s most important base in the central Pacific Ocean. The seizure of New Britain was therefore necessary to protect the base at Truk, and the surrounding islands had to be controlled as well, in order to secure Rabaul. While the main efforts of the Army and Navy would be aimed at the southwest Pacific area – i.e. the Philippines, Malaya, Singapore, Netherlands East Indies and other surrounding areas that made up the so-called “Southern Resources Area” – both the Army and Navy therefore assigned units to operations in the South Pacific.
In the plans which received imperial sanction on 5 November 1941, the Army’s South Seas Detachment was assigned the task of seizing first Guam, then airfields in the Bismarck Islands, in order to eliminate the threat posed by the enemy. Since the operation in the South Pacific was seen as the Navy’s responsibility, however, the Navy’s Special Landing Forces were to take over the occupation of Guam at an appropriate time, after which they would cooperate with the Army in occupying Rabaul. It was further specified that the South Seas Detachment would be replaced by the Special Landing Forces and withdrawn to the Palau Islands as soon as possible. The Navy’s Fourth Fleet, based in Truk, would be responsible for supporting both the Guam and the Rabaul-Bismarcks operations. A sea-borne assault on Rabaul was accordingly made on 22 January 1942 by the Special Landing Forces, with the support of both land-based and carrier-based aircraft, and the town quickly captured.
While these operations were being carried out, the Japanese Army and Navy, faced with the unexpectedly rapid success of their operations in the Philippines, Malaya and Netherlands East Indies, had to decide upon their next steps. Briefly speaking, Japan’s options included continuing westward into India; invading the Australian mainland; invading New Guinea, the Solomons, Fiji and Samoa, in order to cut off Australia from the United States; and driving eastward towards Hawaii. The Navy High Command wanted to invade Australia, in order to eliminate it as potential springboard for a counter-offensive by the Allies, but the Army balked at this because it would require an excessive commitment of manpower. The Navy therefore settled for the lesser option. The Fourth Fleet, with the XI Air Fleet (the Navy’s land-based air force in the Pacific theatre), was ordered to assault Lae, Salamaua in New Guinea, Port Moresby in Papua, and the Solomon Islands.
In compliance with this strategy, Zero fighters of the Chitose Air Corps moved to Rabaul on 31 January. Shortly afterwards, on 2 and 5 February, Kawanishi Type 97 “Mavis” flying boats of the Yokohama Air Corps bombed Port Moresby for the first time, and the air war over New Guinea was underway. On 9 February, Gasmata (on New Britain’s southern coast) was occupied, and work begun on an airstrip. To carry out further operations, the 4th Air Corps was newly created, with a nominal strength of 27 fighters and 27 bombers. It was placed under the command of the 25th Air Flotilla, and its headquarters was located in Rabaul. On 24 February, aircraft from the 4th Air Corps began bombing Port Moresby.
On 7 March 1942, the Japanese High Command decided upon the operations which would follow the so-called “First Stage Operations,” which had been aimed at the occupation of the Netherlands East Indies and other areas of the Southern Resources Area. The second stage of operations which was thus adopted called for the continuation of major offensive operations in order to secure a long-term, unbeatable politico-strategic situation, after which additional active measures would be taken aimed at forcing Great Britain to capitulate and making the United States lose the will to fight.1 As part of this new strategy, the decision was made to continue the advance in the Solomons and New Guinea area, with the aim of eventually cutting off the supply route between the United States and Australia. The 7 March decision therefore confirmed what was already being executed. Lae and Salamaua on the northeastern New Guinea coast were occupied on 8 March. Two days later, the Tainan Air Corps (one of the fighter units deployed to Rabaul as part of the new strategy) sent eleven of its Zero fighters to Lae, which became an exceedingly busy advanced airbase.2
Until the end of July 1942, the naval air units based at Rabaul and Lae became intensely involved in flying missions over the Owen Stanley Range to attack Port Moresby, or other Allied bases on the New Guinea mainland. Such operations consisted of either bombing missions with fighter escort, or sweeps by fighters alone. The Japanese fighter units at this time were also kept extremely busy intercepting Allied air attacks on the Japanese bases. This phase of the air war was characterized by the lack of clear superiority by either side. Although the Australians and Americans often lost more aircraft in individual air battles, Allied air strength did not diminish significantly. On the other hand, the Japanese, although suffering fewer losses, saw a slow decline in the quality of their forces as highly-trained and experienced pilots were lost and replaced by less and less experienced ones. This period was, therefore, somewhat of a stalemate, as the Japanese could not batter the Allied air forces enough to drive them out of New Guinea.
The commitment of Army air forces to the South Pacific
The next stage in Japanese air operations over New Guinea involved the deployment of Japanese Army air forces in the region. After the Americans landed on Guadalcanal Island in the Solomons on 7 August 1942, the Japanese air forces based in Rabaul became involved in a two-front operation. Now they were forced to make increasingly greater efforts in the Solomons, while continuing their campaign against New Guinea (which still principally meant Port Moresby). The air battle in the Solomons would be fought principally by naval aircraft, and, as this commitment grew, the Army’s air forces would play a greater role over New Guinea.
The American counter-attack at Guadalcanal came as a complete surprise to the Japanese. In their estimate of the world strategic situation in March 1942, the Japanese High Command had concluded that the Americans would not mount a major counter-attack before 1943. On 12 August the Army and Navy High Commands agreed that the American landing on Guadalcanal was only a local tactical move, and the island could be easily recaptured. This view began to change after the Battle of the Tenaru River on 21 August, when the Japanese Army’s Ichiki Detachment, numbering some 900 men, made the first attempt to retake Henderson Field and was almost completely wiped out. The Japanese Navy High Command now realized that it would take more than a simple operation to retake Guadalcanal, and that controlling the air around the island was a prerequisite for success. The Navy felt, however, that it alone was unable to make the necessary commitment in terms of air forces, due to the depletion of its air units in Rabaul. In late August it therefore asked the Army to send some of its forces to reinforce the air effort in the Solomons and New Guinea area.3
The Army considered the Navy’s request, and almost immediately rejected it. First of all, the Army was not inclined to make a major commitment in the South Pacific area, because it still felt that its traditional area of responsibility was the Asian mainland, while the Pacific Ocean area was the traditional responsibility of the Navy. This had been the understanding since the establishment of the Japanese Army and Navy in the late 19th Century, and while there was no formal written agreement to this effect, the Army and Navy’s doctrines, training, tactics, strategy and equipment were all based upon it. Over the years the Army’s air units had been prepared almost solely for fighting a war with Japan’s traditional enemy on the continent, Russia. The Army had never even considered the possibility of conducting air operations in the New Guinea-Solomons area, and recognized that it knew almost nothing about the geographic, climatic and other conditions of the South Pacific. Not only was the Army extremely reluctant to commit its air forces in such circumstances, but it suspected that the Navy actually did have additional air forces in quieter areas of the Pacific which it could commit to the South Pacific.
The Army formally replied to the Navy in late August. Besides the reasons given above, the Army explained that its air forces were spread out all over Manchuria, China, Burma and Sumatra, and in addition had to defend the Japanese homeland from possible threats from the North Pacific area. There were, it claimed, no personnel or aircraft that could be spared for the South Pacific. The Army also pointed out that its air forces had been trained and prepared for mainland operations, and were ill-suited for conducting operations or deployments over large expanses of water, which would be the case if they were committed to this new theatre. Furthermore, it was mentioned that there were no overland air routes to the South Pacific front which Army air units might follow, and that airfields and other necessary facilities were too unprepared there for them to operate properly. Thus, no agreement was reached at this stage concerning the deployment of Army air forces to the South Pacific.
In mid-September a further attempt to retake Henderson Field which the Army mounted, using the Kawaguchi Detachment, also failed. As preparations commenced for yet another attempt involving the 2nd Division, the need for regaining command of the air around the Solomons was keenly recognized by Army planners. Gradually, opinion within the Army High Command began tilting towards the deployment of Army air forces to the region. In late October a proposal was produced by the Operations Section of the Army General Staff for the assignment of two fighter and two light bomber sentais (air groups) to support Army operations in New Guinea. This, however, was only intended as a temporary measure to help out the Navy while its air units were committed to the Guadalcanal campaign. (In fact, by then the Navy’s major bombing missions against Port Moresby from Rabaul had all but ceased, except for night raids by one or a few planes at a time, as more and more Navy planes were sucked into the Guadalcanal campaign.) As soon as Port Moresby was captured, it was intended that the Army air forces would be pulled out again.
The issue was settled shortly afterwards. From 28 October, Takushiro Hattori of the Operations Section, Army General Staff, visited the New Guinea-Solomons front, including XVII Army headquarters on Guadalcanal. His report dated 11 November called for, among other things, the deployment of army air forces to the region in order to regain air superiority. In mid-November, the Army and Navy High Commands and the Government produced an estimate of future American air power which projected that the Americans would have in the South Pacific some 11,000 army and navy first-line planes by December 1942, and 24,500 by December 1943. It was recognized that the most urgent need facing Japan was to increase her air power.
Faced with looming defeat on Guadalcanal, and with setbacks in their drive on Port Moresby where Japanese forces had begun withdrawing from Kokoda on 26 October, the Army finally decided to commit some of its air forces to the South Pacific. On 18 November an “Army-Navy Central Agreement on Operations in the South Pacific Area” was signed, and the 6th Air Division was committed to the New Guinea front. This, it should be noted, was only a temporary arrangement to support the Navy’s operations – that is, the Army units would be “loaned” until the Navy’s air forces recovered or certain victorious conditions (such as the occupation of Port Moresby) were attained. In accordance with the agreement, sixty Nakajima Type 1 “Oscar” fighters of the 11th Sentai reached Rabaul via Truk on 18 December, and almost immediately became involved in air defence operations. By the end of the month they were flying missions against targets on mainland New Guinea, such as Buna, some of these as joint missions with Navy aircraft. On 29 December, heavy bomber units of the Army were ordered to deploy from Burma to New Guinea.
Six weeks later, on 3 January 1943, another Army-Navy Central Agreement was signed which designated the areas of responsibility of the Army and Navy’s air units. The Army air forces were given the mission of supporting the ground forces on New Guinea and providing their air defence, and supporting the transport of supplies to New Guinea. The Navy air forces would be responsible for air operations in the Solomons, and for air operations in New Guinea other than those assigned to the Army.4
While the decision to withdraw from Guadalcanal was made at the end of 1942, on 4 January the Army and Navy High Commands ordered that operations on New Guinea were to be continued. The purpose of Japan’s operations in the South Pacific was to be to “secure a position of superiority”. Lae, Salamaua, Wewak and Madang on New Guinea were to be strengthened or occupied, and the area north of the Owen Stanleys was to be secured so that it could function as a base for operations aimed at Port Moresby.5 The Japanese then had 164 Army and 190 Navy aircraft on their bases at Rabaul and the surrounding area. At this stage, therefore, the Japanese had decided to abandon the southern Solomons but still intended to continue offensive operations in New Guinea, aimed at the eventual capture of Port Moresby.
Thereafter, Japanese air operations over New Guinea were conducted principally by the Army, operating out of Wewak and other bases. In addition to bombing raids on Allied airbases, the Japanese air forces also had to take on ground support missions (although never conducted as closely as was the case with the Allied air and ground forces), combat air patrol over their own airbases and escort missions of ship transports operating around New Guinea. As was the case with the Japanese Navy aircraft operating against Port Moresby in mid-1942, however, the Japanese never really gained the initiative in the air, and instead were gradually pressed into the defensive.
The Japanese were acutely aware of the gradually growing strength of the Americans during this period. At the end of January 1943, the Japanese Army estimated that American strength in the New Guinea area was 300 aircraft – the same as the combined strength of the Japanese Army and Navy. They estimated, however, that the Americans were producing 4,000 aircraft per month, of which the South Pacific would receive 480 (and the New Guinea front at least 80) aircraft per month. Judging that the Americans would suffer losses of 50 per cent per month, the Japanese Army projected that the Americans would have 700 aircraft in the New Guinea area by June, and 950 by September. Compared to this, the combined strength of the Japanese Army and Navy in the New Guinea-Solomons area was projected to grow to possibly 350 in June, but was not expected to exceed that number at any time.6 The Japanese were therefore clearly aware that if the current situation continued, the Americans would gradually attain a sheer superiority in numbers through 1943.
After the Japanese successfully withdrew from Guadalcanal in early February 1943, the next major setback which befell them was the Battle of the Bismarck Sea on 2-3 March that year. In this action, an entire convoy of transports carrying the 51st Division and a large amount of heavy weapons and supplies earmarked for the reinforcement of Lae, was sunk in the Dampier Straits, along with four out of eight escorting destroyers. As a result of this disastrous defeat, which occurred even though the Japanese had provided the convoy with what they believed was an adequate fighter escort, the Japanese were forced to realize that they could no longer run major convoys of transports in areas where the Americans were able to operate their bombers more or less freely. This posed obvious problems for the supply of the Japanese troops on New Guinea.
Following the Bismarck Sea battle, the Army reconsidered its entire New Guinea strategy, including the possibility of abandoning New Guinea outright and withdrawing to a new defensive line. This option was not adopted, however, because the Navy’s operations – not only in the New Guinea area but also throughout the South Pacific – would be constricted by such a pullback by the Army. In addition, no new defensive line to which the Army might safely fall back was prepared, and in any case, such a retreat would only expose the Philippines, Celebes and other Japanese-held islands in the South Pacific to air attack. Joint Army-Navy studies which were held on 14 March confirmed this policy, and the Army continued to try to hold its current positions in New Guinea.7