This was the Australian offensive to the east from the Aitape area in the direction of Wewak on the north coast of Japanese-occupied North-East New Guinea against Lieutenant General Goro Mano’s 41st Division within Lieutenant General Hatazo Adachi’s 18th Army (December 1944/11 August 1945).
This Aitape-Wewak campaign was one of the last campaigns of World War II whe, in the period between November 1944 and August 1945, Major General Jack E. S. Stevens’s (from 26 July 1945 Major General Horace C. H. Robertson’s) Australian 6th Division, with air and naval support, fought the Japanese 18th Army in northern New Guinea. The Australians considered the undertaking to be a 'mopping up' and, though ultimately successful in clearing the Japanese forces from the coastal areas and driving them inland, the campaign was fought in very difficult jungle conditions, resulting in a high level of casualties from combat and disease. As Japan was already on the verge of defeat, the casualty rate led to questions about whether or not the campaign could be justified in strategic terms.
It was in 1942 that the Japanese occupied the Aitape region in northern New Guinea as part of their general advance to the south. On 22 April 1944, however, US Army forces landed and recaptured the area in 'Persecution'. After this the area was developed as base from which to support the continuing Allied drive westward along the north coast of New Guinea as a stepping stone toward General Douglas MacArthur’s plan to turn to the north and retake the Philippine islands group. As the preparations for this drive were started, it was decided that defence of the area would be passed to Australian forces so that US troops could be freed for service elsewhere. Early in October 1944, therefore, men of the the Australian 6th Division, together with support personnel from the 3rd Base Sub Area, began to arrive at Aitape to relieve the US garrison. The first unit to arrive was the 2/6th Cavalry Commando Regiment, which began patrol operations almost immediately.
The Japanese strength in the Aitape area comprised some 30,000 to 35,000 men of the 18th Army. This formation had suffered heavily during the campaign of 1943/44 to retake Salamaua and Lae campaign in 1943–1944, and also in its failed attack on the US garrison at Aitape in July 1944. As a result, the Australians believed that they faced elements of Major General (from April 1945 Lieutenant General) Masutaro Nakati’s 20th Division, Lieutenant General Heisuke Abe’s 41st Division and Lieutenant General Hidemitsu Nakano’s 51st Division, each reduced to about a single brigade in real strength. The Japanese ground forces lacked air and naval support, many of the men were ill, and all of the men were short of food, with resupply efforts being limited to occasional deliveries by aircraft or submarine.
By contrast, the Australian troops were better equipped, more fully fed and had superior medical and other support services. They also had a modest degree of air support from the RAAF’s No. 71 Wing, which included Nos 7, 8 and 100 Squadrons equipped with Bristol Beaufort medium bombers, while aerial reconnaissance was provided by Commonwealth Boomerang reconnaissance fighter and Commonwealth Wirraway multi-role aircraft of No. 4 Squadron. Naval support was provided by Commander Bill Dovers’s Wewak Force, which supported the landing at Dove Bay, and included the Australian sloop Swan, minesweepers Colac,Dubbo and Deloraine as well as craft of the 1st New Guinea Motor Launch Flotilla.
'King Grab' was entrusted by General Sir Thomas Blamey, commanding the Allied Land Forces South-West Pacific Area, to Stevens’s Australian 6th Division. This entire undertaking followed the relief of the US forces (Major General William H. Gill’s 32nd Division, Major General Robert S. Beightler’s 37th Division, Major General Rapp Brush’s 40th Division and Major General Robert B. McClure’s [from October 1944 Major General William H. Arnold’s] Americal Division as well as one infantry regiment) in New Guinea, New Britain and Bougainville by Lieutenant General Vernon A. H. Sturdee’s Australian 1st Army, a change which was completed by the end of December 1944.
The 1st Army’s headquarters were located at Lae in North-West New Guinea, and controlled the 6th Division at Aitape, 100 miles (160 km) to the east of the border with Netherlands New Guinea, and the 8th Brigade at Madang, 250 miles (400 km) farther along the coast to the east. Between them was the 18th Army (now comprising Nakai’s 20th Division, Abe’s 41st Division and Nakano’s 51st Division), cut off in this area by mid-1944.
From New Guinea, where it had been containing the Japanese in Wewak from its base at Madang, the Australian soldiers of Major General Alan H. Ramsay’s (from April 1945 Robertson’s) 5th Division moved to New Britain and came into patrol contact with troops of General Hitoshi Imamura’s 8th Area Army (Lieutenant General Yashushi Sakai’s 17th Division, Lieutenant General Sadaaki Kagesa’s 38th Division, the 39th Independent Mixed Brigade and the 65th Independent Mixed Brigade) holding the isolated Japanese base area for the South-West Pacific round Rabaul, located on the northern end of the island.
On Bougainville, the northernmost island of the Solomons group, the Australian forces of Lieutenant General Stanley G. Savige’s II Corps was disposed with Major General William Bridgeford’s 3rd Division and Brigadier J. R. Stevenson’s 11th Brigade at Torokina and, to provide a guard for airfields against the remote contingency of a Japanese attack, the headquarters of Brigadier A. W. Potts’s 23rd Brigade and one of its battalions were sent to Green island, 75 miles (120 km) to the north of Bougainville, one battalion to Emirau island north of New Ireland, and one to Treasury island south of Bougainville.
The headquarters of Lieutenant General Harukichi Hyakutake’s (from 1 April 1945 Lieutenant General Masatane Kanda’s) 17th Army, comprising Kanda’s (from 1 April 1945 Lieutenant General Tsutomi Akinaga’s) 6th Division and the 38th Independent Mixed Brigade, was at Buin at the south-eastern end of Bougainville.
Blamey decided that the 1st Army should take the offensive and issued instructions that on Bougainville the II Corps was to destroy the Japanese forces in the south of the island, that in New Britain the 5th Division was to prevent the Japanese in the Rabaul area from expanding their perimeter south of Rabaul and also to carry out offensive patrolling and minor raids, and that in New Guinea the 6th Division was to contain and if possible to destroy the 18th Army in the area of Wewak. In carrying out these operations, however, the Australians were under strict instruction not to become involved in any major, and therefore costly, combat. Blamey had three main reasons for taking his decision for offensive operations: the isolated Japanese garrisons were tying down Australian forces which could be used elsewhere, and would continue to do so until destroyed or fully dispersed; his troops would deteriorate if they remained on the defensive; and it was politically desirable to regain control over the areas of which Australia was the guardian. Another element in Blamey’s thinking was the fact that in some areas the Japanese were farming good land for their own use, to the detriment of the local inhabitants.
Despite the fact that they were numerically inferior in each area, the Australians began to take offensive action in December 1944, and by the end of February 1945 had reversed the situation in these areas. On Bougainville the II Corps had gained control of the greater part of the centre of the island; in New Britain the 5th Division was in touch with Japanese outposts covering the perimeter round Rabaul; and in New Guinea the 6th Division had advanced to the east from the area of Aitape and was in touch with the 18th Army half way between Aitape and Wewak. The offensives in all of these areas continued to a greater or lesser extent until the Japanese surrendered in August 1945. On Bougainville island the main Japanese force, now greatly reduced in strength by sickness and battle casualties, was by June hemmed into a small area around Buin, while smaller groups were confined around Bonis and in the Kieta area. This was approximately the position when the war ended. The Australian campaign on Bougainville cost 2,088 casualties, including 516 men killed, but it was estimated that 8,500 Japanese had been killed and 9,800 had died of illness or malnutrition during the campaign. The number of Japanese, including civilians, who surrendered was 23,571.
On New Britain the 5th Division made no attempt to attack the main Japanese defences covering Rabaul, for to defend them the 8th Area Army had some five experienced and comparatively well-fed though understrength divisions on the peninsula, which is joined to the main part of New Britain by an isthmus 25 miles (40 km) wide. The Australians decided to secure the isthmus as a base from which to keep patrol watch on the main defences and to prevent the Japanese forces infiltrating into the main part of the island. By a time late in February 1945, after a series of small amphibious landings, men of the 5th Division were within striking distance of the isthmus on both the north and south coasts, and in three weeks of fighting during March in very difficult country had driven the Japanese from their positions covering it. By 28 March the 5th Division was firmly established on the isthmus, and thereafter confined its operations to patrolling to watch the main Japanese positions to give warning of any threatened offensive. The campaign in New Britain cost the Australians 214 casualties, of which 42 were killed and 122 wounded in the isthmus fighting, and at the end of the war some 90,000 Japanese surrendered. More than 11,000 Japanese surrendered in New Ireland, to which no American or Australian troops had been sent. The number who surrendered in the two islands included 19 generals, 11 admirals and 4,700 other officers.
In New Guinea, following the defeat of his forces on the Driniumor river in July, Adachi had withdrawn the rest of his strength from its forward positions and, in the operational lull which followed, ordered his men to focus their attentions on foraging operations into the Torricelli mountains and around Wewak. During this period there had been very little contact between the Japanese and US forces in the area, and US forces had remained on a primarily defensive footing, restricting their operations to limited patrols around their position on the Driniumor river. Upon the arrival of the Australian 6th Division, however, Stevens responded with Blamey’s orders for limited offensive action with the decision to clear the remaining Japanese forces from the coastal area of New Guinea.
Initially tasked with the defence of the port, airfield and base facilities at Aitape, the 2/6th Cavalry Commando Regiment was now ordered to advance eastward in the direction of Wewak to destroy the remnants of the 18th Army, the regiment’s patrols spearheading the main Australian advance of the 6th Division.Beginning in November 1944, the offensive was directed along two axes: Brigadier J. E. G. Martin’s 19th Brigade moved along the coast toward the Japanese base area at Wewak, while the 2/6th Cavalry Commando Regiment, working with Australian New Guinea Administrative Unit detachments, advanced into the Torricelli mountains, driving toward the area of Maprik, which provided the Japanese with most of their food supplies. While the advance was under way, Brigadier M. J. Moten’s 17th Brigade was assigned the task of building a defensive position around the airfield and base facilities at Aitape, while Brigadier R. King’s 16th Brigade was held in reserve.
On 19 December the 19th Brigade crossed the Danmap river and began to move toward the east in an effort to cut the main Japanese line of communication. A series of minor actions followed, but no major engagements took place and at the end of four weeks the brigade had reached Wallum, about 45 miles (72.5 km) to the east of Aitape. A week later, on 24 January 1945, the 16th Brigade relieved the 19th Brigade, while the 17th Brigade continued the advance toward the west through the Torricelli mountains.
The operations were characterised by prolonged small-scale patrolling interspersed with small-scale company attacks. Progress was slowed by the difficulties of transporting supplies overland or by barge, and by the flash flooding of a number of the rivers the Australians had to cross: on one occasion, seven men of the 2/3rd Battalion drowned in the swollen waters of the Danmap river, which had risen suddenly after a torrential downpour. After Dogreto Bay had been occupied, the Australian supply problems eased to some degree. On 16 March, the airfields at But and Dagua on the coast were occupied, although fighting continued inland from these over the course of the following fortnight.
In the Torricelli mountains the 17th Brigade continued its advance against determined Japanese resistance, but by 23 April 1945 had secured Maprik. The capture of Maprik allowed the Australians to begin the construction of an airfield 8 miles (13 km) away at Hayfield, and the completion of this facility on 14 May made it possible for reinforcements and supplies to be delivered by air.
Elsewhere the 19th Brigade had begun its assault on Wewak at a time early in May. The Australian light cruiser Hobart, Australian destroyers Arunta and Warramunga, Australian sloop Swan and British light cruiser Newfoundland (of the British Pacific Fleet) as well as RAAF aircraft bombarded the Wewak defences. On 11 May, a landing at Dove Bay by 'Farida' Force was undertaken to encircle Wewak and prevent the escape of its garrison. Wewak fell on the same day as the 19th Brigade occupied its airfield. Even so, the fighting around Wewak airfield continued until 15 May, when men of the 2/4th Battalion, with armoured support, attacked Japanese positions overlooking the airstrip.
After this, the remaining Japanese in the area withdrew into the Prince Alexander mountains to the south of Wewak. To counter this, the 16th Brigade was dispatched to follow them up, and push them toward the 17th Brigade, which advanced to the east in the direction of Maprik. The Japanese were thus coraled by the 6th Division holding the Maprik and Wewak areas and by Brigadier M. A. Fergusson’s 8th Brigade (based on Madang) operating in the Hansa Bay and Ramu river area. These operations continued until 11 August, by which time the 16th Brigade had reached Numoikum, about 14 miles (23 km) from Wewak, while the 17th Brigade had captured Kairivu, 15 miles (24 km) from Wewak. At this time word was received that the Japanese government had begun discussing terms for a possible surrender, and offensive operations were therefore halted.
By the end of the campaign, the Australians had lost 442 men killed and 1,141 wounded, as well as another 16,203 men listed as 'sickness casualties' from malaria, skin diseases, typhus and other tropical ailments. More than 9,000 Japanese were killed while 269 were captured during the fighting, and about 14,000 other died from disease or starvation. Following the end of hostilities in New Guinea, about 13,000 Japanese surrendered.
As noted above, even as the campaign continued the strategic value of the operation was called into question once it had become clear that the fighting would have little impact upon the outcome of the war. In that regard, it was argued that the Japanese forces in area of Aitape and Wewak posed no strategic threat to the Allies as they advanced toward the Japanese home islands, and that if they could be isolated and contained they could be left to 'wither on the vine', like many isolated island garrisons, as their supplies ran out.
Nevertheless, at the time that the operation was planned there was no way for the Australian commanders to know when the war would come to an end and there were arguably sound political and operational reasons to carry out the campaign. By a time late in 1944, the Australian army had taken a secondary role in the fighting and there was a political and indeed emotional need for Australia to demonstrate that it was sharing the burden in the Pacific war. As New Guinea was an Australian territory at the time, it was argued that there was a responsibility to clear the Japanese from that area. As a result of manpower shortages in the Australian economy, however, the government had requested the army to find a way to reduce its size, while at the same time requiring it to maintain forces to undertake operations against the Japanese into 1946 if necessary. In order to do that, it has been argued that there was a requirement to clear the Japanese force which had been bypassed in order to allow the Australian garrison forces in these areas to be reduced.