'Postern' was the Allied clearance of Lieutenant General Hatazo Adachi’s 18^th Army from the area of Lae and Finschhafen in the Huon peninsula region of North-East New Guinea by the US and Australian forces of General Douglas MacArthur’s South-West Pacific Area command (4 September 1943/26 April 1944).

Lae is located on the north-western corner of the Huon Gulf, and therefore at the western end of the Huon peninsula’s southern coast, at the mouth of the Markham River. The centre of the local gold-mining industry, in 1941 Lae was the capital of Morobe district and the largest settlement in North-East Guinea with a population of 11,500 including 1,500 Europeans, and possesses a good anchorage. Its airfield was located at Malahand, some 4 miles (6.4 km) to the north-east. Lae was also the key to the Ramu and Markham river valleys to the west, where flat terrain of sand and gravel with relatively little jungle cover was ideal for building roads and airfields. The Japanese took Lae in their 'Sr' (ii) operation of 8/10 March 1942.

Finschhafen is located on the south-western tip of the Huon peninsula of New Guinea, and there was a small but undeveloped anchorage just to the north, as well as a larger but less well protected roadstead to the south-west at Hanisch Harbour. Finschhafen was occupied by the Japanese on 11 March 1942, and Allied air attacks failed to drive them out or prevent them from completing an airstrip to the north of the village.

The campaign for Salamaua and Lae, of which 'Postern' was the major element, was a series of actions in the New Guinea campaign as Australian and US forces sought to capture two major Japanese bases, one at Salamaua and the other at Lae, as a precursor to the planned clearance of the Japanese forces on the Huon peninsula top provide the shortest possible access route to the main Japanese base area around Rabaul on the large island of New Britain. The campaign to take the area of Salamaua and Lae began with the Australian attack on Japanese positions near Mubo on 22 April 1943, and ended with the fall of Lae on 16 September 1943.

In July 1942, the US Joint Chiefs-of-Staff had approved the planning and implementation of a series of operations against Rabaul, located on the island of New Britain and the Japanese strategic bastion foe operations in eastern New Guinea and the islands off it. The presence of this bastion area blocked any Allied advance to the west along the northern coast of New Guinea and toward the Philippine islands group, and to the north in the direction of the main Japanese naval base at Truk in the Caroline islands group. In accordance with the overall Allied 'Germany first' strategy of defeating Germany before Japan, the immediate aim of these operations was not the defeat of Japan but merely the reduction of the threat posed by Japanese aircraft and warships based at Rabaul to air and sea communications between the USA and Australia.

By inter-Allied agreement, during March 1942 the Pacific theatre had been divided into two separate commands, each with its own commander-in-chief. The South-West Pacific Area, which included Australia, Indonesia and the Philippine islands group, came under General Douglas MacArthur’s supreme command, while most of the remainder, known as the Pacific Ocean Areas, came under Admiral Chester W. Nimitz’s supreme command. There was no overall commander, and no authority to resolve competing claims for resources, set priorities or reallocating resources from one command to the other, so any and all such decisions had to be made on the basis of compromise, co-operation and consensus.

Rabaul fell within MacArthur’s area of responsibility, but the initial operations in the south-eastern part of the Solomon islands group fell within Nimitz’s area of responsibility. The Japanese reaction to Task One, which was the seizure of the southern part of the Solomon islands group starting with 'Watchtower', was more violent than anticipated and it was February 1943 before the Guadalcanal campaign had been brought to a successful conclusion. MacArthur’s forces meanwhile fought off a series of Japanese offensives in Papua, at the eastern tip of New Guinea, in 'Mo' (ii) (the Kokoda Track campaign), 'Re' (the Battle of Milne Bay), the Battle of Buna and Gona ('Lilliput'), the Battle of Wau, and the Battle of the Bismarck Sea.

After these victories, the strategic and operational initiative in the South-West Pacific Area passed to the Allies, and MacArthur pressed ahead with his plans for Task Two. At the Pacific Military Conference in Washington, DC, during March 1943, the plans were reviewed by the Joint Chiefs-of-Staff, who could not supply all the manpower and matériel which MacArthur demanded. The plan was therefore scaled down to become the 'Elkton' plan, and the capture of Rabaul was postponed to 1944. On 6 May, MacArthur’s headquarters in Brisbane issued Warning Instruction No. 2 informing subordinate commands of the plan, which divided the Task Two operations on the New Guinea axis into three parts: firstly, the occupation of Kiriwina and Woodlark islands and the establishment of powerful air forces on them ('Chronicle'); secondly, the seizure of the area bounded by Salamaua, Lae, Finschhafen and Madang and the establishment of air forces in it ('Postern', 'Michaelmas' and 'Dayton'); and thirdly, the occupation of the western part of New Britain, the establishment of air forces at Cape Gloucester, Arawe and Gasmata, and the occupation or neutralisation of Talasea ('Director', 'Backhander' and 'Appease').

The second part was assigned to General Sir Thomas Blamey’s New Guinea Force and, as a result, it became clear that any military offensive in 1943 would be effected mainly by the Australian army, just as it had been during the bitter campaigns of 1942.

At Rabaul, the Japanese maintained separate army and navy headquarters, which co-operated with each other but were responsible to different higher authorities. The naval forces came under Vice Admiral Jinichi Kusaka’s South-East Area Fleet, while the army forces came under General Hitoshi Imamura’s 8^th Area Army, which comprised Lieutenant General Harukichi Hyakutake’s 17^th Army in the Solomon islands group, Adachi’s 18^th Army in New Guinea, and Lieutenant General Giichi Itahana’s 6^th Air Division based at Rabaul. As a result of the Battle of the Bismarck Sea, the Japanese decided to attempt the despatch of no more convoys to Lae, but instead to land troops at Hansa Bay and Wewak for onward movement to Lae by barge and submarine. In the longer run, the Japanese hoped to complete a road over the Finisterre range and thence to Lae through the Ramu and Markham river valleys.

Imamura ordered Adachi to capture the Allied bases at Wau, Bena Bena and Mt Hagen and, to support these operations, Imperial General Headquarters transferred Lieutenant General Einosuke Sudo’s 7^th Air Division from the Netherlands East Indies to New Guinea to become part of Lieutenant General Kumaichi Teramoto’s 4^th Air Army which, on 27 July 1943, had been assigned to the 8^th Area Army to control Itahana’s 6^th Air Division, Sudo’s 7^th Air Division, the 14^th Air Brigade and a miscellany of other squadrons. By June, Adachi had three divisions in New Guinea: Lieutenant General Shigeru Katagiri’s 20^th Division recently arrived from the Palau islands group and now located around Madang , Lieutenant General Heisuke Abe’s 41^st Division also recently arrived from the Palau islands group and now located round Wewak, and Lieutenant General Hidemitsu Nakano’s 51^st Division now located in the Salamaua area. Adachi thus had some 80,000 men under command, and of his three primary formations only the 51^st Division was in contact with Australians. Like Blamey, Adachi faced formidable difficulties of transportation and supply just to bring his troops into battle.

During 1942 the Japanese had established major bases on the north-eastern coast of North-East New Guinea in the large town of Lae and the small town of Salamaua some 22 miles (35.5 km) to the south. Salamaua was a staging post for attacks on Port Moresby, such as the Kokoda Track campaign, and when these attacks failed, the Japanese turned the port into a major supply base. Logistical considerations meant that the area of Salamaua and Lae could accommodate a garrison of only 10,000 personnel in the form of 7,500 soldiers and 2,500 sailors. The defences were centred on the 'Okabe' Detachment, which was Major General Toru Okabe’s brigade-sized force of Nakano’s 51^st Division.

In January 1943, the 'Okabe' Detachment attacked the Australian base at Wau, about 25 miles (40 km) distant to the south-west, but was defeated, and senior Allied commanders began to focus their attention on Salamaua, which could be attacked by troops flown to the airfield at Wau. This also diverted attention from Lae, which was a major objective of 'Cartwheel', the Allied grand strategy for MacArthur’s South-West Pacific Area command. It was decided that the Japanese would be pursued toward Salamaua by the Major General Stanley G. Savige’s Australian 3^rd Division, which had come together at Wau after retraining in Australia as separate brigades and on 22/23 April assumed responsibility for the area of Wau and Bulolo from 'Kanga' Force. Commanded from 12 May by Major Norman L. Fleay, this latter was an ad hoc Australian composite unit which had been created for operations in Papua on 23 April 1942 from elements of the 1^st Independent Company, the 2/5^th Independent Company and the New Guinea Volunteer Rifles (NGVR), and in the course of its short existence undertook a number of small raids and reconnaissance operations around Lae and Salamaua before being absorbed into the 3^rd Division.

The Australian army had decided to form 'Kanga' Force as a guerrilla unit with the initial task of undertaking a reconnaissance of Japanese troops at Lae and Salamaua, and later of starting a limited offensive to harass and destroy Japanese personnel and equipment in the area. With this in mind, the reinforcement platoon of the 1^st Independent Company, which had reached Port Moresby by sea and been renamed as the Independent Platoon Port Moresby, was sent to reinforce the NGVR, which was currently the only Allied unit in the area of Wau and Bulolo.

In May 1942, after the Battle of the Coral Sea had ended the Japanese 'Re' and 'Mo' (ii) plans to take Milne Bay and Port Moresby in landings from the sea, Blamey and MacArthur, the commanders-in-chief of the Australian forces and the Allied South-West Pacific Area respectively, agreed that it was time to launch the limited offensive on which they had agreed. As part of this offensive, MacArthur requested that ground raids be initiated against Lae and Salamaua to destroy the Japanese bases located there and, if possible, to occupy the airfields. On 12 May Fleay was ordered to concentrate his command in the Markham river valley in preparation for a surprise attack on Lae and Salamaua.

On 23 May, the 2/5^th Independent Company reached Wau airfield from Port Moresby, as a reinforcement for 'Kanga' Force, by means of the aircraft of the US 21^st Troop Carrier Squadron. Together with the Independent Platoon Port Moresby and the NGVR, this brought 'Kanga' Force up to strength, and as the situation developed the unit was ordered to begin a limited offensive designed to harass and destroy Japanese troops and equipment in the area. The supplies needed by 'Kanga' Force were delivered by air if this was possible, or otherwise shipped to the mouth of the Lakekamu river in small craft, transported up the river to Bulldog in canoes, and then carried over the Bulldog track by native porters.

By June most of 'Kanga' Force was concentrated at Wau, although there were elements of the 2/1^st and 2/5^th Companies spread as far as Bulwa, and elements of the NGVR at Mapos. The NGVR was still watching the Salamaua sector from Mubo, while other elements were covering the inland routes from the Markham and Wampit rivers. As Fleay attempted to juggle his forces and relieve the exhausted NGVR detachments, his orders were clarified and work began on planning a number of raids in the area. At this stage it was believed that there were as many as 2,000 Japanese troops at Lae and another 250 at Salamaua. Against this 'Kanga' had 700 men, although only 450 were fit for battle. Moreover, the requirement to defend the many tracks through the Bulolo valley meant that Fleay was numerically very straitened for the achievement of his mission.

Fleay decided to keep his main strength in the Bulolo valley and to launch a number of raids in the area. These would be concentrated on the Japanese force at Heath’s Plantation, for this was an obstacle to any large-scale movement against Lae; on the Lae area to destroy aircraft, dumps and installations and to test the defences with a view to operations on a larger scale in the future; and on the Salamaua area to destroy the wireless station, aerodrome installations and dumps.

On 29 June, a pair of raids was launched against Heath’s Plantation and Salamaua. The raid on Heath’s Plantation, at Lae, was carried out by 58 men, mainly of the 2/5^th Independent Company, but the barking of guard dogs warned the Japanese of the raid’s arrival, and the Australian company commander was killed and two men were wounded before the group retired without achieving any useful result. The raid on Salamaua by 71 men of the 2/5^th Independent Company and the NGVR was altogether more successful, for at least 100 Japanese were killed for the loss of only three Australians slightly wounded. The Australians also captured a small amount of equipment and a number of documents, including marked maps, sketches and Japanese orders.

Post-raid reconnaissance reports indicated that the Japanese were starting to reinforce Lae and Salamaua, and this was of some concern to the Allies in connection with the defence of the important air installation at Wau and the need to secure the crest of the Owen Stanley mountain range in that area. The 2/7^th Independent Company was therefore flown into Wau in October 1942 as a reinforcement. Anticipating an attack by the Japanese, Blamey ordered Brigadier Murray J. Moten’s 17^th Brigade of the 6^th Division from Milne Bay to reinforce Wau and relieve 'Kanga' Force, and on 16 January 1943 the Japanese launched an offensive against Wau.

Imamura, commander of the 8^th Area Army at Rabaul, had correctly deduced the Australian intentions and the strength of 'Kanga' Force, had accordingly decided to forestall the Australian plan to take Lae, and ordered Adachi’s 18^th Army to secure 'important areas to the west of Lae and Salamaua'. On 29 December, Adachi ordered the 102^nd Regiment and other units of the 'Okabe' Detachment to move from Rabaul to Lae for an immediately advance inland to capture Wau.

Imamura was facing a resourceful, resolute and aggressive opponent, who also had the benefit of very good intelligence. Allied 'Ultra' codebreakers were able to read the Japanese shipping codes, and, by 3 January 1943, Allied commanders knew in advance about the force that Adachi was planning to send from Rabaul to Lae, although they did not know the force’s ultimate destination. Blamey opted not to leave the initiative to the Japanese and wait for their objective to become clear, but immediately ordered the 17^th Brigade to move from Milne Bay to Wau on 4 January 1943, whereupon Moten was also to assume command of 'Kanga' Force and defend Wau.

The Commander, Allied Air Forces, South-West Pacific Area was Major General George C. Kenney, and this officer ordered Brigadier General Kenneth N. Walker, heading the V Bomber Command, to carry out a major bombing attack at dawn on the shipping in Rabaul harbour before it could depart for New Guinea. Walker was unhappy with this as it would require his bombers to take-off and rendezvous be night, and instead recommended an attack at 12.00. Kenney appreciated Walker’s concerns but was insistent: he preferred bombers out of formation by night to nicely disposed bombers shot down by Japanese fighters which were sure to effect an interception by day. Poor weather precluded participation by bombers from Australia, so all that was available were the aircraft in Papua, namely six Boeing B-17 Flying Fortress and six Consolidated B-24 Liberator heavy bombers. Despite Kenney’s orders, Walker attacked Rabaul harbour at 12.00 on 5 January, the bombers meeting heavy anti-aircraft fire and continuous fighter attacks. Forty 500-lb (227-kg) and 24 1,000-lb (454-kg) bombs were dropped from from an altitude of 8,500 ft (2590 m), and the formation claimed hits on nine ships totalling 50,000 tons. Two B-17 bombers were shot down, including that carrying Walker. Post-war analysis revealed the sinking of only one Japanese merchant vessel, the 5,833-ton Keifuku Maru, and damage to two other merchant vessels as well as the destroyer Tachikaze.

On 6 January the convoy carrying the 'Okabe' Detachment departed Rabaul for Lae. Forewarned by 'Ultra' intelligence, USAAF and RAAF aircraft spotted, shadowed and then attacked the convoy, which was shielded by low clouds and Japanese fighters. The Allies claimed to have shot down 69 Japanese aircraft for the loss of 10 of their own. A Consolidated Catalina flying boat of the RAAF made a night bombing attack on the convoy and sank the transport Nichiryu Maru, and while Japanese destroyers rescued 739 of the 1,100 troops on board, the ship took down with her all of the 'Okabe' Detachment's medical supplies. Another transport, Myoko Maru, was so badly damaged at Lae by North American B-25 Mitchell medium bombers of the USAAF that it had to be beached. Nonetheless, the convoy reached Lae on 7 January and landed about 4,000 troops.

Between 10 and 16 January, the 'Okabe' Detachment moved along the coast to the south in barges to Salamaua, where it assembled and readied itself to attack Wau. On 16 January, the Japanese encountered a platoon of the 2/7^th Independent Company, and after a brief action in which their commander was killed, the Australians retreated to Skindewai. Instead of pursuing the Australians directly, however, Okabe opted to advance on Wau down an old and little-used track through difficult country parallel with the Black Cat track used by the Australians, and the two sides therefore lost contact. Okabe’s object was to disguise the strength and objective of his force, and as a result took the Australians by surprise. The Japanese crossed Komiatum hill, advanced to Mubo and then took the track to the west, a route chosen so as to avoid observation by Allied aircraft as the Japanese hacked their way through the jungle by day: the hill range to the east of Wau is about 1,500 ft (455 m) high and not especially arduous to cross, but in parts new tracks had to be prepared without the fact being spotted by Allied aircraft. As the troops had to carry all of their food, ammunition and equipment, the advance was difficult and took longer than had been anticipated, but eventually the Japanese reached a peak from which they could look down into the Bulolo river valley and over Wau.

By this time the Japanese were running short of food, and Okabe ordered an immediate attack to seize the Allies' food supplies. The Japanese movement through dense jungle had caused Okabe’s units to lose touch with each other, though, so the resulting attack was delivered piecemeal and with only insufficient preparation.

Meanwhile, the first element of the 17^th Brigade, part of the 2/6^th Battalion, had started to leave for Port Moresby by sea on 9 January, the rest of the battalion following over the next two nights. The 2/7^th Battalion departed Milne Bay in the army transport Taroona on 13 January and the 2/5^th Battalion in Duntroon on the following day.

The prospects for the 17^th Brigade to beat the Japanese to Wau did not seem good. At this time, there were in New Guinea only 28 Douglas C-47 transport aircraft in the hands of the understrength 6^th, 21^st and 33^rd Troop Carrier Squadrons of Colonel Paul H. Prentiss’s US 374^th Troop Carrier Group. The activities of these aircraft had to be shared with those of the Buna and Gona front, so each combat area had an allocation of just 14 aircraft, which worked out to 10 serviceable aircraft per day for each. The C-47 could carry 27 passengers or 10,000 lb (4536 kg) of freight, so the movement of a single infantry battalion therefore amounted to 60 aeroplane loads, and of a brigade to 361 aeroplane loads. Between 10 and 19 January, the 2/6^th Battalion was flown in from Port Moresby to reinforce 'Kanga' Force. In the process three aircraft crashed, and poor flying weather forced many aircraft to return without landing: Moten was twice forced to return to Port Moresby before reaching Wau on the third attempt. Bad weather continued over the following week, limiting air operations and sometimes precluding them entirely. Part of the 2/5^th Battalion arrived on 27 January.

In the way of Okabe’s advance was A Company of the 2/6^th Battalion under Captain W. H. Sherlock. Okabe ordered the attack on 28 January and, forced from his position, Sherlock fell back onto a nearby spur. For much of the afternoon, Japanese frontal attacks were beaten back by Australian mortar and machine gun fire, and efforts to infiltrate Sherlock’s positions were defeated by a bayonet attack led by Sherlock in person. By 18.00 Sherlock’s company had expended all of its mortar ammunition and was running short of small arms ammunition, and was at the same time being hit by mortar bombs and swept by machine gun fire. Sherlock held on through the night, and was killed the next day as his company tried to break through the Japanese lines.

Farther to the south-east, the fighting at Buna ended on 23 January, freeing aircraft to support Wau, and 52 new C-47 aircraft of Colonel Lorry N. Tindal’s US 317^th Troop Carrier Group had reached Australia in a movement from the USA expedited in response to urgent requests from MacArthur arising from the fighting for Buna. The aircraft were now flown to Port Moresby to help the 374^th Troop Carrier Group fly the 17^th Brigade into Wau as there were now as many as 40 aircraft per day available.

On 29 January, 57 planeloads arrived, bringing most of the 2/7^th Battalion and the remainder of the 2/5^th Battalion. Although subjected to small arms fire as they landed and unloaded, 40 aircraft made 66 trips on the following day. Their cargoes included two dismantled 25-pdr gun/howitzers of the 2/1^st Field Regiment with 688 rounds of ammunition. These were landed in the morning and had been assembled and bought into action before 12.00, shelling a concentration of 300 Japanese between the villages of Wandumi and Kaisenik. The Japanese were also attacked by Bristol Beaufighter heavy fighters of No. 30 Squadron RAAF flying in the close air support role. Three Dakota aircraft were damaged when one overshot the runway on landing and crashed into two others. One was repaired, but the other two were a total loss.

Japanese attacks during this day reached the corner of the airstrip, but the Japanese were forced to fall back under enormous pressure.

On 31 January, 35 aircraft made 71 trips, and 40 aircraft made 53 trips on 1 February, bringing in reinforcements including the 2/3^rd Independent Company to raise the strength of 'Kanga' Force to more than 3,000 men. By 4 February, Okabe was threatened with encirclement and was forced to order a withdrawal. With all hope of capturing Wau gone, Okabe was ordered to abandon the attempt.

The Japanese now attempted to sever the flow of Allied reinforcements flying to Wau by bombing the airstrip, but it was the rainy season and the Japanese were confronted by the same weather conditions which were hampering the Allies. Aircraft which did set off from Rabaul were not able to locate the Wau airstrip and returned without accomplishing anything. Not until 6 February was there an aerial engagement. Eight Bell P-39 Airacobra fighters of the 40^th Fighter Squadron were patrolling at an altitude of 12,000 ft (3660 m) over Wau, after escorting five C-47 transports, when they sighted 24 Japanese aircraft: in the resulting air battle, the American pilots claimed 11 Mitsubishi A6M Reisen 'Zero' fighters and Mitsubishi Ki-21 'Sally' bombers shot down. Meanwhile, eight Curtiss P-40 fighters of the 7^th Fighter Squadron, also on an escort mission, sighted 12 Japanese aircraft as they bombed the airstrip at Wau. The transports which the P-40 fighters were escorting turned back while the fighters engaged the Japanese, claiming seven aircraft shot down. At this time, there were four Dakota transports on the ground at Wau and another five were circling as they waited to land, one of these being shot down. A Dakota on the ground was damaged, and a CAC Wirraway was destroyed by a bomb blast.

Major General Ennis C. Whitehead’s Advanced Echelon headquarters in Port Moresby ordered three squadrons based there to join the battle. Lockheed P-38 Lightning fighters of the 39^th Fighter Squadron engaged a dozen Japanese fighters over Wau, shooting one down. A few minutes later, the 9^th Fighter Squadron, only recently converted to the P-38, downed another Japanese fighter, while P-40 fighters of the 41^st Fighter Squadron surprised six Japanese fighters, shooting down three of them. The airmen thus claimed to have shot down 23 Japanese fighters and one bomber, and Australian gunners of the 156^th Light Anti Aircraft Battery claimed another bomber and two fighters.

From its creation in May 1942 until its absorption into the 17^th Brigade on 15 February 1943, 'Kanga' Force had lost 30 officers and 319 men, including four officers and 48 men of the 2/6^th Battalion. The Australians counted 753 Japanese dead and, together with the 361 lost on Nichiryu Maru and numerous airmen, the total of Japanese dead rose to about 1,200.

The New Guinea Force wished to pursue the Japanese, but was prevented from the attempt by logistical difficulties. The Japanese now prepared to make another effort to capture Wau. This time, the Japanese planned, they would approach from the north, building a road from Markham Point into the Snake river valley. From there the advance was to head down the valley to Wau. The 51^st Division was earmarked for the task, but this formation suffered heavy losses en route to New Guinea in the Battle of the Bismarck Sea during 2/4 March 1943 when the 'Operation No. 81' convoy was savaged by Allied air attack. This was an event which strongly impressed the Japanese command with the danger now posed by the steadily increasing capabilities of Allied air power: in this battle Allied aircraft had sunk all eight transport vessels and five out of eight destroyers, and the Japanese lost more than 2,890 men as well as large quantities of matériel. A new plan was therefore devised under which an overland line of communication was to be established down the Ramu and Markham river valleys. In June, Adachi was ordered to prepare another attempt to capture Wau. Road construction was carried out at great hardship to the troops involved, but the road was still incomplete when the Allied air landing at Nadzab and sea landing near Lae led to the suspension of the work. Now free of Japanese threat, Wau now became an important Allied jumping off point for the Salamaua and Lae campaign by Savige’s 3^rd Division from 22 April.

With a force which initially comprised only the 17^th Brigade and the 2/3^rd, 2/5^th and 2/7^th Independent Companies, Savige was instructed to turn the area of Wau into an active operational zone for mobile defence. At this time. the Allies believed that there were 5,500 Japanese around Lae and Salamaua, with between 6,000 and 8,000 at Madang and from 9,000 to 11,000 at Wewak. Ordered not to attack Salamaua directly, Savige decided to establish firm bases as far forward as possible and to harass the Japanese with offensive patrols. Only small forces could be maintained in the forward area, however, and no useful military purpose was served by attacks and raids which were not properly organised, supported by superior fire and fully driven home.

The Japanese were dug in on the Pimple, Green Hill and Observation Hill along the main track from Wau to Mubo. On 24 April the 2/7^th Independent Company attacked the Pimple and Green Hill, Four aircraft strafed the Japanese position and then the company advanced in two columns supported by mortar fire, but the Japanese were firmly entrenched on the steep slopes of the feature and checked the Australians. On the following day another attack, supported by aircraft and the 1^st Mountain Battery, limited to just 50 rounds per gun, also failed. On 7 May a company attack was again launched against the Pimple, and once more failed. On 9 May the Japanese themselves attacked in the Pimple area and surrounded the forward Australian company, which was not relieved until the afternoon of 11 May, by which time it had withstood eight attacks by parts of two Japanese battalions.

The 2/3^rd Independent Company had been probing deeply, and establishing that the Japanese were holding Bobdubi ridge only lightly, obtained permission to attack it. On 3/4 May the Japanese were pushed off part of Bobdubi ridge, and in the day which followed the Japanese moving up to retake it were also driven back. From Bobdubi ridge, the 2/3^rd Independent Company was able to harass the Japanese with raids and ambushes which cost the Japanese much manpower and matériel. So successful were the 2/3^rd Independent Company’s tactics that Savige decided to order the company not to overextend itself as it could not be aided should it run into unexpected difficulties.

Even so, the pressure in the area of the Bobdubi ridge was maintained, and on 11 May an Australian patrol found that the Japanese had abandoned their positions on the part of the ridge from which they had not been driven, quickly occupied it, and exchanged fire with the Japanese on Komiatum ridge and the main track it accommodated. The Japanese reacted in strength to this threat to their line of communications, launching a full-scale attack supported by guns and mortars on 14 May, and forced the Australians to withdraw. On 15 May, more than 100 Japanese aircraft attacked the Australian positions in three heavy raids. The Japanese maintained their air attacks in the following days, but generally against targets farther to the Australian rear. On 17 and 18 May large formations of Japanese aircraft raided Wau airfield.

Late in May, the 2/6^th Battalion relieved the 2/7^th Battalion and the headquarters of Brigadier Heathcote H. Hammer’s 15^th Brigade, and another battalion of that brigade began to arrive in Savige’s area. During May Beaufighter heavy fighters and Douglas Boston medium bombers of the RAAF, together with B-25 Mitchell medium bombers of the USAAF, attacked Madang and Lae, as part of the programme to maintain and indeed to increase the Allied pressure on these bases. The RAAF now had three squadrons committed largely to the Salamaua operations, and four squadrons based at Milne Bay for use largely in attacks on shipping and in reconnaissance. Two Catalina flying boat squadrons based on Cairns in northern Queensland also played a part in the operations in New Guinea by mining the harbours used by the Japanese, making night raids and supporting the coastwatcher network in Japanese-held territory.

Instructions were now issued for the seizure of an advanced base on the coast within 60 miles (100 km) of Lae, this being the farthest distance landing craft could carry troops in one night. The site selected as Nassau Bay, whose occupation would make it possible for the force in the Mubo area to be supplied, in part at least, by sea. In addition to the bay, the high ground around Goodview Junction and Mt Tambu and the ridge running from this to the sea were to be seized.

The object of all these operations toward Salamaua was to draw as much of the the Japanese strength as possible away from Lae, and Salamaua itself was not to be assaulted until after 'Postern' had taken Lae. So in the time before 'Postern' was launched, the Allies made every effort to persuade the Japanese that Salamaua was the main Allied objective.

On 19/20 June there were signs that the Japanese were about to anticipate the Allied attack. They were patrolling aggressively, and on 20 June Japanese aircraft made more than 80 bombing attacks on the Australian positions. The right forward company of the 2/6^th Battalion, holding a wide area toward Nassau Bay, came under sharp fire during the afternoon of 20 June, and on the morning of the following day the battalion drove back a strong Japanese attack before facing a still more determined Japanese effort during the afternoon of the same day. A fresh Australian company then reinforced that which was under attack. At the fall of night the Japanese withdrew after losing as many as 100 men, but renewed their attacks on 22 and 23 June, when the Australian defence was aided by Beaufighter strafing attacks on the track the Japanese had to use to reach the Australian positions. That afternoon the Japanese attacks ended. The 150 Australians on Lababia ridge had lost 11 men killed and 12 wounded, but had driven off the attacks of two Japanese battalions totalling about 1,500 men of whom 41 were killed and 131 wounded.

At much the same time as the end of the 'Chronicle' seizure of Woodlark island and the Kiriwina islands group, and start of the 'Toenails' landing on New Georgia island in the Solomon islands group, the US 162^nd Regimental Combat Team of the 41^st Division landed at Nassau Bay on the night of 29/30 June and on the following morning moved out of its initial beach-head at the start of an undertaking which lasted to 6 July. The landing was planned and launched to give the Allies a beach-head in which to establish a supply point to shorten their lines of communication for the proposed attack on Salamaua as part of 'Postern''.

The 162^nd RCT’s Intelligence and Reconnaissance Platoon had placed lights on islands lying offshore between Nassau Bay and Mageri Point to guide the invasion flotilla and meanwhile, in accordance with an agreement reached by the 162^nd RCT’s commander, Colonel Archibald R. MacKechnie, and Savige, D Company of the 2/6^th Battalion was marching from Lababia ridge toward the mouth of the Bitoi river to divert Japanese attention from Nassau Bay. One of this battalion’s platoons was also despatched was sent to the landing beach to set up the lights which would guide the landing craft to the right beach, and A Company of the Papuan Infantry Battalion reconnoitred to Cape Dinga just to the south of Nassau Bay.

Before the landing, B-25 Mitchell medium bombers of the US 5^th AAF attacked Japanese strongpoints along the Bitoi river, and Douglas A-20 attack bombers hit a supply dump on the southern side of Nassau Bay on 29 June.

Comprising the combined elements of the 162^nd RCT and Australian units, 'MacKechnie' Force embarked at Mort Bay at dusk on 29 June 1943. PT-142, PT-143, PT-120 of the US 7^th Fleet carried 210 men of the 1/162^nd Infantry, with PT-68 providing escort. Some 29 LCVPs, two captured Japanese barges of the 2^nd Engineer Special Brigade, and one LCM of the 532^nd Engineer Boat and Shore Regiment carried the other 770 men of the 1/162^nd RCT to Mageri Point. The landing force was organised in three waves, but rough seas, heavy rain and poor visibility meant that the landing force lost contact with the escorting PT-68 after leaving Mort Bay. PT-142 led the first wave of landing craft, but as a result of poor visibility the first wave overshot Nassau Bay by 3 miles (4.8 km), and time was lost as the craft of the first wave turned back and located the rest of the convoy.

At Nassau Bay, a platoon of the 2/6^th Battalion’s D Company from Mubo set landing markers to guide the landing craft into the beach-head. As the first wave with PT-142 arrived, PT-143 also arrived with the second wave, and the landing craft intermingled and landed on the same stretch of beach in surf up to 12 ft (3.7 m) high. The landing craft were pushed far up onto the beach, 17 of them broaching and filling with water. After unloading a bulldozer, the LCM was able to proceed back out to sea, retrieve the troops on PT-142 and then return to the beach, where it too was swamped. Fortunately for Americans, the landing had been unopposed and 770 men landed at Nassau Bay. The landing craft which had broached were wrecked, and most of the radios had been damaged by salt water. PT-143 returned to the advanced PT-boat base at Morobe, while PT-142 and PT-68 remained to provide seaward protection.

The 300-man Japanese garrison had pulled back after Commander Torashige Tsukiokare had been killed by the detonation of a bomb which struck his headquarters earlier in the day, and fled into the jungle in the belief that the bulldozer was a tank.

The third wave of landing craft, with PT-120, arrived hours after the first two waves, and it was decided that no landing would be made until after the surf had abated. The craft took shelter in a cove down the coast until the storm had subsided, and then returned to Nassau Bay before failing to find the beach-head and returning to Mageri Point.

During the night which followed the landing, Companies A and C of the 162^nd RCT established defence lines, 300 yards (275 m) to the north and south respectively of the landing beach. A platoon of D Company of the 2/6^th Battalion defended the western flank. No contact was made with the Imperial Japanese that night.

At dawn on 30 June, the beach was cleared of all ammunition, equipment and supplies, and machine guns salvaged from the wrecked landing craft were established as part of the beach defences. Company C moved to the south to reach the Tabali river just to the west of Cape Dinga in an effort to link with the Papuan Infantry Battalion located to the south of Cape Dinga. Company A patrolled to the north as far as the southern arm of the Bitoi river, and halted after running into Japanese mortar and machine gun fire. Patrols reported that the Japanese were present in some strength. Company A, along with D Company of the 2/16^th Battalion, attempted to strike the Japanese western flank, but was stopped. D Company of 2/6^th Battalion ran out of ammunition and was relieved by a detachment of engineers from the crews of the wrecked landing craft. Two platoons of Company C rushed up from the south to join Company A, at 15.00 started to move forward and by 16.50 had moved past the scattered Japanese opposition to reach the southern arm of the Bitoi river.

On learning of the US landing, Adachi ordered 150 men of 3/66^th Regiment to move to the south from Salamaua. The Papuan Infantry Battalion began to attack the rear of the detachment of the 3/102^nd Regiment at Cape Dinga and started to move toward the Nassau Bay beach-head. At 16.30 on 30 June, the remainder of Company C defending the southern flank reported that Japanese troops were crossing the Tabali river just to the south of its position, and was ordered to withdraw to the beach-head’s southern defensive flank and there to hold a line between the beach and the swamp lying a short distance inland. Before the remainder of Company C could withdraw, however, the Japanese attacked its rear and flank, and the Americans had to fight their way north, losing their commander and four men on the way.

At the beach-head a defence line was hastily prepared utilising engineers, part of the Australian D Company and headquarters personnel. At dusk one of Company C’s platoons reached the southern perimeter of the beach-head defence line, and then the Japanese made a series of attacks on the Allied perimeter right through the night using mortars, machine guns, rifles and grenades. Small groups of Japanese tried to infiltrate the positions, but were beaten off. The Japanese then withdrew before the start of day on 1 July, and Allied patrols hunted down straggling Japanese during the morning.

The easternmost company of the 2/6^th Battalion advanced to the coast near the southern arm of the Bitoi river, driving off a company of Japanese, and other patrols found that the Japanese had withdrawn from the area to the north of Nassau Bay.

On 2 July, the third wave of landing craft reached Nassau Bay, and the escorting PT-120 used its guns to attack two Japanese-held villages to the south of Nassau Bay near Cape Dinga. More landing craft towed by trawlers also arrived at Nassau Bay. The easternmost company of 2/6^th Battalion made contact with the northern edge of the US perimeter along the southern arm of the Bitoi river. Patrols by Company C found that Japanese at Cape Dinga had been evacuated.

The 'MacKechnie' Force then sent patrols toward Napier. By 4 July four pieces of 75-mm (2.95-in) artillery had been landed at Nassau as a most important reinforcement, and more than 1,400 US troops were ashore. PT-120 and PT-152 carried 140 troops to Nassau Bay to be taken aboard landing craft for delivery onto the beach, and on 6 July PT-120 and PT-149 transferred another 135 men while escorting 11 landing craft to Nassau Bay.

The Allies had thus gained a very useful supply point for the attack against Salamaua, and heavy artillery landed at Nassau Bay was able to shell Salamaua. The Papuan Infantry Battalion advanced along the coast ahead of the 162^nd RCT to reach Lake Salus on 9 July and then push on to Tambu Bay.

During the morning of 7 July the 2/6^th Battalion had attacked Observation Hill and by the fall of night had taken most of this feature. On the next day the leading Australian company advanced a stage farther toward a creek where it was to link with the Americans from the Bitoi river. On 9 July, now supported by the US field guns whereas formerly there had been only two mountain guns behind them, five Australian companies pressed on with aggressive patrols until, on 10 July only 75 Japanese survived in the area, and their line of retreat had been cut. On 12 July the Pimple was occupied. On 13 July there was a general advance and on 14 July Mubo airstrip and Green Hill were taken. The Japanese still stoutly defended Old Vickers, where they were entrenched to defend the track to Salamaua, and on 7 and 9 July had already stopped attacks by the 58^th/59^th Battalion.

The 3/162^nd RCT had been assembled at Nassau Bay by 12 July as the first stage in a movement to establish artillery at Tambu Bay. On 21 July the US battalion reached Tambu Bay and supplies were unloaded there. The US task was to capture Scout Ridge, overlooking the bay, but after attacks during 22 July failed, the 2/162^nd RCT was sent to reinforce the attackers.

On 16 July a company of the 2/5^th Battalion had assaulted Mt Tambu with great dash and captured all but its northern knoll. The Japanese counterattacked several times during that night, supported by mortar bombs and the shells of a mountain gun. A second Australian company reached the area during the morning of the next day. During the night of 18 July the Japanese attacked and almost encircled the two Australian companies, and on the next day there developed a fierce struggle. By 14.30 the Japanese had suffered losses so severe that they yielded the southern slopes of the hill to the Australians. Farther to the north, on 15 July, after mortar and machine gun fire, two platoons of the 2/3^rd Independent Company attacked Ambush Knoll to the south of Namling, while the 58^th/59^th Battalion attacked toward Bobdubi in another effort to cut the Japanese line of communication. One platoon of the 2/3^rd Independent Company drove the Japanese from their forward positions and the other thrust them from Orodubi, and that night the Japanese abandoned Ambush Knoll. The attack by the 58^th/59^th Battalion was upset, however, by Japanese countermoves. In a renewed attack on 17 July the 2/3^rd Independent Company again carried out its task, but the 58^th/59^th Battalion was again checked.

The establishment of the base area at Nassau Bay had by now made it possible to deliver and then to supply a substantial quantity of artillery, and by 23 July two US field artillery battalions, two Australian field batteries, the Australian Mountain Battery and 2/6^th Survey Battery, and four anti-aircraft batteries were in place. On the right flank the US regiment was still making little progress, and in the last week of July the 2/162^nd RCT completed its arrival at Tambu Bay and was given the task of capturing what was now termed 'Roosevelt Ridge' after Lieutenant Colonel Archibald Roosevelt, one of the 162^nd RCT’s battalion commanders. The battalion’s attack gained and held a foothold on the ridge. The Japanese were well dug in and not to be driven out by frontal attacks, however, and Roosevelt’s battalion, aided by Papuan patrols, was now employed to cutting the Japanese supply route to the west.

On 28 July a flanking attack by a company of the 2/6^th took a feature forward of Ambush Knoll. The same day 58^th/59^th Battalion, supported by the fire of artillery, mortars and machine guns, at last took the stubborn Old Vickers position and drove the Japanese from Bobdubi ridge. It was estimated that in the six weeks to 6 August, the 15^th Brigade had killed 400 Japanese for a loss of 46 men killed and 152 wounded, an indication of the increasing tactical superiority of the attackers.

The 42^nd Battalion, leading Brigadier Raymond Monaghan’s 29^th Brigade of Major General Edward J. Milford’s 5^th Division, was moved forward into the Nassau Bay area, marched to the north and and moved into position between the 162^nd RCT on the right and the 17^th Brigade, to which it was subordinated. As a preliminary to the capture of Mt Tambu, the 42^nd Battalion occupied Davidson ridge between Tambu and 'Roosevelt Ridge'. Then on 13/14 August the 2/162^nd RCT took 'Roosevelt Ridge' after a heavy artillery barrage which stripped it of all vegetation. The 15^th Brigade’s attack began on 14 August after 29 heavy bombers had saturated Coconut Ridge with devastating effect, and guns, mortars and machine guns had brought down a barrage on the defenders. A company of the 2/7^th Battalion then attacked up a cliff so steep that the men had to crawl on hands and knees, but by early in the afternoon they had gained the North Coconuts position. On the night of the 16/17 August the Japanese abandoned South Coconuts.

The 2/6^th Battalion began its attack on Komiatum ridge on 16 August. After the supporting artillery had fired about 500 shells into the Japanese positions, two companies attacked and in 25 minutes had occupied the objective. The Japanese in the Mt Tambu area were now surrounded, their routes to the north being cut on Komiatum and Davidson ridges. It was expected that lack of food (patrols had discovered that this was delivered only on every third day) would cause the Japanese to attempt a break-out on the third night. On 19 August patrols of the 2/5^th Battalion found Goodview Junction deserted, and the 1/162^nd RCT occupied Tambu without opposition.

The 15^th Brigade now pressed toward the track leading to Salamaua. On 17 August, after a bombardment, two platoons of the 2/3^rd Independent Company advanced, one occupying the junction of the track linking Bobdubi and Salamaua with another track from the south without meeting opposition, but the other platoon was held. Heavy fighting developed, and the Japanese launched strong counterattacks. On 19 August Savige that the Japanese avenues of escape between Komiatum and Bobdubi ridges must be closed. On the next day the brigade attacked on a wide front, and the 58^th/59^th Battalion cut the Komiatum track in several places.

In preparation for the new offensive, Savige was instructed that he should organise his force in a manner which would allow it to operate without air supply from 28 August, when supplies landed from the sea would be all that it would receive. From 21 August the 29^th Brigade began to relieve the 17^th Brigade (except for the 2/7^th Battalion attached to the 15^th Brigade), which had been fighting its way through the jungle-covered mountains from Wau toward Salamaua since January. The Australians rapidly advanced towards Salamaua, but Savige ordered that the Japanese were not to be pressed so hard that they would resort to an early evacuation, which would have strengthened the Japanese in the Lae area.

On 26 August, Savige and the headquarters of his 3^rd Division were relieved by Milford and the headquarters of his 5^th Division, and it was this latter formation which undertook the final operations around Salamaua. This small town was occupied by the 42^nd Battalion on 11 September, a week after the Lae offensive opened and five days before the 7^th Division and Major General George F. Wootten’s 9^th Division entered Lae.

On 8 September, Adachi had ordered Nakano to abandon Salamaua and fall back on Lae with what was left of his 51^st Division. Nakano had already evacuated his hospitalised men and artillery to Lae, and on 11 September began to withdraw his main body. By this time, the Japanese appreciated that Blamey intended to cut off and destroy the 51^st Division. After discussing the matter with Imperial General Headquarters in Tokyo, Imamura and Adachi called off their plans to capture Bena Bena and Mt Hagen and instructed Nakano to move overland to the northern coast of the Huon peninsula while the 20^th Division moved from Madang to Finschhafen, sending one regiment down the Ramu river valley to assist the 51^st Division. The Salamaua garrison assembled at Lae on 14 September, and the Japanese evacuated the town over the next few days. It was a group involved in this retreating which encountered the US 3/503^rd Parachute Infantry, and the Japanese hurriedly altered their route before the Australians could intercept them.

The 3^rd Division’s campaign in the middle six months of 1943 had achieved impressive results. A great part of the 18^th Army's strength had been diverted from the areas which were to be the objectives of the offensive scheduled for September, when veteran divisions would have been rested and retrained, landing craft made available, and air superiority further increased. At the same time immensely valuable experience had been gained in jungle tactics and also in methods of supply. For the first time Australian infantry and independent companies had worked closely together in a lengthy campaign, and each had learned from the other. Artillery had been used on a scale hitherto unattained in mountain warfare in New Guinea. Doctrines were developed which gave the Australians decisive tactical and administrative superiority over the Japanese in bush warfare. In the six months to August 1943 the strength of the 18^th Army had been depleted and dispersed while, behind the front on which the 3^rd Division fought, the Allied strength in the South-West Pacific Area had greatly increased.

To the north of the fighting for Salamaua, the plans had been finalised for the main element of 'Postern', which was the seizure of Lae in a pincer movement, involving an amphibious assault to the east of the town, and an airborne landing near Nadzab, some 30 miles (50 km) to the west of it. The campaign formed the initial part of the great offensive which the Allies, most especially the USA and Australia, with New Zealand and Free Dutch support, launched in the Pacific late in 1943 and resulted in the Japanese being pushed north from Lae at the mouth of the Markham river to Sio on the north-eastern coast of North-East New Guinea over the course of a four-month period. The coastwise advance was characterised by a number of US and Australian amphibious landings, while the inland advance was undertaken largely by the Australians. Throughout the Huon peninsula campaign, the Allied forces had a major advantage through the quantitative and qualitative edges which their industrial and economic infrastructures had achieved over those of the Japanese by this stage of World War II, while the Japanese were severely hampered by a lack of supplies and reinforcements resulting from the very effective Allied interdiction efforts at sea and in the air.

The Huon peninsula campaign was preceded by the amphibious landing of 4 September by troops of Wootten’s Australian 9^th Division to the east of Lae on the southern coast of the Huon peninsula’s eastern extremity in the area between Hopoi and the mouth of the Busu river, thereby cutting off the garrison of Lae. This was followed by an advance to the west along the coast toward Lae, where the force landed from the sea was to link with Major General George A. Vasey’s Australian 7^th Division. This latter formation had been flown from Port Moresby into Tsili Tsili on the Watut river, down which it advanced to the Markham river at Nadzab, which had been taken on 5 September in the first successful US combat parachute assault, and the Australian formation then advanced 50 miles (80 km) down the Markham river toward Lae. Meanwhile, as noted above, Australian and US forces mounted diversionary attacks around Salamaua on the south-east coast of the Huon Gulf.

The operational scene for 'Postern' had been set by the fact that by 1943 the Japanese had ended their expansion into MacArthur’s South-West Pacific Area. Their advance in North-East New Guinea and Papua had been halted in the previous year by the blocking action which the Australians had fought along the Kokoda Trail (otherwise Kokoda Track) and so prevented the Japanese 'Mo' (ii) capture of Port Moresby on the Papuan south coast to the north-east of Cape York, the most northerly tip of mainland Australia. Subsequent Japanese defeats at Milne Bay at the end of 'Re', Buna and Gona at the end of 'Ri', Wau to the south-west of Salamaua, and on Guadalcanal in 'Watchtower', had forced the Japanese back onto the strategic and operational defensive. As a result of these victories, the Allies were able to seize the initiative in the region in mid-1943 and began making plans to continue to push the Japanese back in New Guinea.

Allied planners began to develop their plans for the course of operations in the Pacific and the land areas in and round it with the ultimate object of retaking the Philippine islands group and the eventual capture of the Japanese home islands. In the South-West Pacific Area, the linchpin of Japanese land, sea and air power was the main base area in and round Rabaul on New Britain island. The reduction of this base area was regarded as the key to Allied success in the South-West Pacific Area, and was formalised in the 'Cartwheel' plan.

In order to achieve this object, the Allies needed a number of major air bases from which the Rabaul area could be bombed and the sea lanes to it from the north and from its to the west, south and south-east could be interdicted. Senior Allied commanders, including MacArthur, decided that two air bases had to be won, one at Lae and the other at Finschhafen. The capture of Lae would provide the Allies with the port from which men and supplies could be delivered up the Markham river valley to Nadzab and and thereby facilitate operations farther to the north-west in the Markham river valley. The capture of Finschhafen, and with it the Huon peninsula, was an important precursor to planned operations on New Britain by providing a natural forward harbour, and opening the probability of controlling the strategically important Vitiaz and Dampier Straits to the south and north of Umboi island between North-East New Guinea and New Britain.

At the time, there were no US ground forces under MacArthur’s command in action against the Japanese, and the task of securing Lae and Finschhafen was therefore allocated to the Australian 9^th Division. This was an experienced veteran formation of the all-volunteer 2^nd Australian Imperial Force, and had fought in the North African campaign, where it had held Tobruk against a German onslaught earlier in the war and been heavily engaged at the 1^st and 2^nd Battles of El Alamein. Early in 1943 the division had been brought back to Australia, and it had subsequently been reorganised and retrained for jungle warfare. With an establishment of 13,118 men, the division comprised Brigadier W. J. Victor Windeyer’s 20^th Brigade, Brigadier Bernard Evans’s (from 10 November 1943 Brigadier Selwyn H. W. C. Porter’s) 24^th Brigade and Brigadier David A. Whitehead’s 26^th Brigade, each of three battalions, together with battalion-level engineer, pioneer, artillery and armoured units attached at divisional level. In support of the 9^th Division, militia infantry units of Brigadier Cedric R. V. Edgar’s 4^th Brigade were also to become in the fighting after the first stages. US forces were also involved, primarily in the provision of logistical, naval and engineering support.

Air support was provided by Air Commodore Joseph E. Hewitt’s No. 9 Operational Group of the RAAF, which included an initial seven Australian squadrons (four at Milne Bay and three at Port Moresby) such as No. 4 Squadron flying the CAC Boomerang fighter-bomber and CAC Wirraway reconnaissance and army co-operation types, and No. 24 Squadron flying the Vultee Vengeance dive-bomber. US warplanes, such as the Republic P-47 Thunderbolt and Lockheed P-38 Lightning heavy fighters of Colonel Neel E. Kirkby’s 348^th Fighter Group and Lieutenant Colonel George W. Prentice’s 475^th Fighter Group, were also used to provide fighter cover for Allied shipping, while heavy and medium bombers of Kenney’s US 5^th AAF flew heavy bombing missions to reduce the Japanese air bases around Wewak and in New Britain, and attacked the Japanese maritime lines of communication in concert with the activities of PT-boats.

The use of wheeled transport in the jungle was impractical, so the Allied logistic effort depended largely on water transport such as landing craft and barges, which moved supplies along the coast, with short-distance overland supply to combat units falling to New Guinea labourers and, at times, the Australian combat troops themselves, supplemented wherever possible by Jeeps.

The primary Japanese formation in this campaign was Adachi’s 18^th Army, which was headquartered at Madang and comprising Katagiri’s 20^th Division, Abe’s 41^st Division and Nakano’s 51^st Division, together with several smaller units included naval infantry and garrison elements. In the Finschhafen area during the middle part of September, the main forces under the overall command of Major General Eizo Yamada, commander of the 1^st Shipping Group, were drawn from the 20^th Division's 80^th Regiment and 26^th Field Artillery Regiment, the 41^st Division's 238^th Regiment, the naval 85^th Garrison Unit and one company of the 51^st Division's 102^nd Regiment. Tactical command was devolved to the local level as a result of the wide dispersal the Japanese units and the area’s indifferent communications. The Japanese units were situated across a large area between the Mongi river to the east of Lae, to Arndt Point, Sattelberg, Joangeng, Logaweng, Finschhafen and Sisi as well as on Tami island. The greatest concentrations were those in the area of Sattelberg and Finschhafen, where the main forces came under Katagiri’s command. It is worth noting that the strength and general capability of the Japanese units had already been reduced to a significant degree by a combination of disease and their commitment to road construction between Madang and Bogadjim.

Like the Allies, the Japanese relied on water transport for the movement of supplies and reinforcements around the New Guinea, using a force of three submarines to avoid interdiction by Allied aircraft, which had inflicted heavy losses during the Battle of the Bismarck Sea. The submarines were augmented by barges, although these latter were available only in limited numbers and very vulnerable to the attack of Allied aircraft and PT-boats. Once supplies had been landed, resupply parties were used to carry the stores overland on foot along a number of key tracks to the main troop concentrations around Sattelberg and Finschhafen.

Air support was provided by Teramoto’s 4^th Air Army, which comprised primarily Sudo’s 7^th Air Division and the 14^th Air Brigade, together with some elements of Itahana’s 6^th Air Division. Based in Wewak, the Japanese aircraft were mainly used to escort Japanese shipping and attack Allied shipping around the main beach-heads during the campaign, with a secondary task of undertaking ground attack missions in support of Japanese troops. Aircraft of the Imperial Japanese navy’s 11^th Air Fleet, based at Rabaul under the command of Kusaka, who was also commander of the South-East Area Fleet, were also available for anti-shipping missions.

Heavy Allied bombing of Japanese airfields around Wewak in August 1943 greatly reduced the number of aircraft available to the Japanese, and severely limited their ability to apply air power throughout the campaign.

In overall terms, therefore, the Japanese forces were short of transport, engineer and logistical support, and were hampered operationally ands tactically by a lack of cohesion resulting from their disparate command structures and poor infrastructures. By way of contrast, the Australian forces had fought together in previous campaigns and were backed by a capable logistical support base able to provide a technical and industrial superiority that the Japanese were unable to match.

Following MacArthur’s directive to secure the airfields at Lae and Finschhafen, Blamey in his capacity as commander-in-chief of the Allied Forces, South-West Pacific Area ordered the capture of Lae and the Huon peninsula by the Australian 9^th Division. T