Operation Postern

'Postern' was the Allied clearance of Lieutenant General Hatazo Adachi’s 18th 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 8th Area Army, which comprised Lieutenant General Harukichi Hyakutake’s 17th Army in the Solomon islands group, Adachi’s 18th Army in New Guinea, and Lieutenant General Giichi Itahana’s 6th 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 7th Air Division from the Netherlands East Indies to New Guinea to become part of Lieutenant General Kumaichi Teramoto’s 4th Air Army which, on 27 July 1943, had been assigned to the 8th Area Army to control Itahana’s 6th Air Division, Sudo’s 7th Air Division, the 14th Air Brigade and a miscellany of other squadrons. By June, Adachi had three divisions in New Guinea: Lieutenant General Shigeru Katagiri’s 20th Division recently arrived from the Palau islands group and now located around Madang , Lieutenant General Heisuke Abe’s 41st Division also recently arrived from the Palau islands group and now located round Wewak, and Lieutenant General Hidemitsu Nakano’s 51st Division now located in the Salamaua area. Adachi thus had some 80,000 men under command, and of his three primary formations only the 51st 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 51st 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 3rd 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 1st Independent Company, the 2/5th 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 3rd 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 1st 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 2/5th Independent Company reached Wau airfield from Port Moresby, as a reinforcement for 'Kanga' Force, by means of the aircraft of the US 21st 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 2/1st and 2/5th 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 2/5th 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 2/5th 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 2/7th 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 17th Brigade of the 6th 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 8th 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 18th Army to secure 'important areas to the west of Lae and Salamaua'. On 29 December, Adachi ordered the 102nd 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 17th 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 2/7th 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 17th Brigade, part of the 2/6th 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 2/7th Battalion departed Milne Bay in the army transport Taroona on 13 January and the 2/5th Battalion in Duntroon on the following day.

The prospects for the 17th 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 6th, 21st and 33rd Troop Carrier Squadrons of Colonel Paul H. Prentiss’s US 374th 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 2/6th 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 2/5th Battalion arrived on 27 January.

In the way of Okabe’s advance was A Company of the 2/6th 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 317th 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 374th Troop Carrier Group fly the 17th 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 2/7th Battalion and the remainder of the 2/5th 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 2/1st 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 2/3rd 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 40th 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 7th 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 39th Fighter Squadron engaged a dozen Japanese fighters over Wau, shooting one down. A few minutes later, the 9th Fighter Squadron, only recently converted to the P-38, downed another Japanese fighter, while P-40 fighters of the 41st 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 156th Light Anti Aircraft Battery claimed another bomber and two fighters.

From its creation in May 1942 until its absorption into the 17th Brigade on 15 February 1943, 'Kanga' Force had lost 30 officers and 319 men, including four officers and 48 men of the 2/6th 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 51st 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 3rd Division from 22 April.

With a force which initially comprised only the 17th Brigade and the 2/3rd, 2/5th and 2/7th 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 2/7th 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 1st 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 2/3rd 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 2/3rd Independent Company was able to harass the Japanese with raids and ambushes which cost the Japanese much manpower and matériel. So successful were the 2/3rd 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 2/6th Battalion relieved the 2/7th Battalion and the headquarters of Brigadier Heathcote H. Hammer’s 15th 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 2/6th 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 162nd Regimental Combat Team of the 41st 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 162nd 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 162nd RCT’s commander, Colonel Archibald R. MacKechnie, and Savige, D Company of the 2/6th 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 5th 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 162nd 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 7th Fleet carried 210 men of the 1/162nd Infantry, with PT-68 providing escort. Some 29 LCVPs, two captured Japanese barges of the 2nd Engineer Special Brigade, and one LCM of the 532nd Engineer Boat and Shore Regiment carried the other 770 men of the 1/162nd 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 2/6th 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 162nd 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 2/6th 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 2/16th Battalion, attempted to strike the Japanese western flank, but was stopped. D Company of 2/6th 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 3/66th Regiment to move to the south from Salamaua. The Papuan Infantry Battalion began to attack the rear of the detachment of the 3/102nd 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 2/6th 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 2/6th 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 162nd RCT to reach Lake Salus on 9 July and then push on to Tambu Bay.

During the morning of 7 July the 2/6th 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 58th/59th Battalion.

The 3/162nd 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 2/162nd RCT was sent to reinforce the attackers.

On 16 July a company of the 2/5th 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 2/3rd Independent Company attacked Ambush Knoll to the south of Namling, while the 58th/59th Battalion attacked toward Bobdubi in another effort to cut the Japanese line of communication. One platoon of the 2/3rd 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 58th/59th Battalion was upset, however, by Japanese countermoves. In a renewed attack on 17 July the 2/3rd Independent Company again carried out its task, but the 58th/59th 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 2/6th 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 2/162nd 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 162nd 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 2/6th took a feature forward of Ambush Knoll. The same day 58th/59th 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 15th 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 42nd Battalion, leading Brigadier Raymond Monaghan’s 29th Brigade of Major General Edward J. Milford’s 5th Division, was moved forward into the Nassau Bay area, marched to the north and and moved into position between the 162nd RCT on the right and the 17th Brigade, to which it was subordinated. As a preliminary to the capture of Mt Tambu, the 42nd Battalion occupied Davidson ridge between Tambu and 'Roosevelt Ridge'. Then on 13/14 August the 2/162nd RCT took 'Roosevelt Ridge' after a heavy artillery barrage which stripped it of all vegetation. The 15th 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 2/7th 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 2/6th 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 2/5th Battalion found Goodview Junction deserted, and the 1/162nd RCT occupied Tambu without opposition.

The 15th Brigade now pressed toward the track leading to Salamaua. On 17 August, after a bombardment, two platoons of the 2/3rd 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 58th/59th 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 29th Brigade began to relieve the 17th Brigade (except for the 2/7th Battalion attached to the 15th 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 3rd Division were relieved by Milford and the headquarters of his 5th Division, and it was this latter formation which undertook the final operations around Salamaua. This small town was occupied by the 42nd Battalion on 11 September, a week after the Lae offensive opened and five days before the 7th Division and Major General George F. Wootten’s 9th Division entered Lae.

On 8 September, Adachi had ordered Nakano to abandon Salamaua and fall back on Lae with what was left of his 51st 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 51st 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 20th Division moved from Madang to Finschhafen, sending one regiment down the Ramu river valley to assist the 51st 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 3/503rd Parachute Infantry, and the Japanese hurriedly altered their route before the Australians could intercept them.

The 3rd Division’s campaign in the middle six months of 1943 had achieved impressive results. A great part of the 18th 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 18th Army had been depleted and dispersed while, behind the front on which the 3rd 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 9th 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 7th 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 9th Division. This was an experienced veteran formation of the all-volunteer 2nd 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 1st and 2nd 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 20th Brigade, Brigadier Bernard Evans’s (from 10 November 1943 Brigadier Selwyn H. W. C. Porter’s) 24th Brigade and Brigadier David A. Whitehead’s 26th Brigade, each of three battalions, together with battalion-level engineer, pioneer, artillery and armoured units attached at divisional level. In support of the 9th Division, militia infantry units of Brigadier Cedric R. V. Edgar’s 4th 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 348th Fighter Group and Lieutenant Colonel George W. Prentice’s 475th Fighter Group, were also used to provide fighter cover for Allied shipping, while heavy and medium bombers of Kenney’s US 5th 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 18th Army, which was headquartered at Madang and comprising Katagiri’s 20th Division, Abe’s 41st Division and Nakano’s 51st 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 1st Shipping Group, were drawn from the 20th Division's 80th Regiment and 26th Field Artillery Regiment, the 41st Division's 238th Regiment, the naval 85th Garrison Unit and one company of the 51st Division's 102nd 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 4th Air Army, which comprised primarily Sudo’s 7th Air Division and the 14th Air Brigade, together with some elements of Itahana’s 6th 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 11th 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 9th Division. The initial focus was upon securing Lae, and the plan created to achieve this involved the 9th Division making an amphibious landing to the east of Lae and the Australian 7th Division moving by air to Nadzab in the Markham river valley after this had been taken in an airborne operation by the US 503rd Parachute Infantry and the 2/4th Field Regiment. From Nadzab, the 7th Division was to advance on Lae from the north-west to support the 9th Division’s westward drive on Lae. At the same time, Savige’s Australian 3rd Division and the US 162nd RCT were already fighting a significant diversionary action around Salamaua.

On 1 September, after completing its training in Queensland and at Milne Bay in eastern New Guinea, the 9th Division embarked in vessels of Rear Admiral Daniel E. Barbey’s VII Amphibious Force as part of what was to be the largest amphibious operation undertaken by the Allied forces in the South-West Pacific Area up to that time: carrying some 8,000 Australian troops (20th and 26th Brigades to be landed on 3/4 September and 24th Brigade on 5/6 September to the east of Lae), Barbey’s force comprised 39 LSTs, 20 LCIs, nine LCTs, 14 transports, 12 submarine-chasers and three other vessels escorted and supported by the US destroyers Conyngham, Flusser, Perkins, Smith, Mahan, Lamson, Mugford, Drayton and Reid. The last was the radar picket which located an approaching Japanese bomber force early enough for it to be intercepted by US fighters. In further Japanese air attacks, LCI(L)-339 was sunk, and LST-471, LST-473, LCI(L)-30, LCI(L)-338, LCL(L)-34l and Conyngham were damaged. On 8 September Perkins, Flusser, Smith and Mahan and on 9 September the fast transports Brooks, Gilmer, Humphreys and Sands bombarded Lae in support of the operation.

Windeyer’s 20th Brigade had been selected to spearhead the assault with a landing at a pair of beaches 16 miles (26 km) to the east of Lae: Red beach to the east of the Busu river’s mouth and Yellow beach near Malahang. Early on 4 September five destroyers fired a heavy six-minute bombardment, and then the 2/13th Battalion led the 20th Brigade ashore, with the brigade’s other organic infantry units, the 2/15th and 2/17th Battalions, landing soon after this in the second and third waves. Unopposed on the ground, the Australian infantry began rapidly to move inland as further reinforcements arrived. About 35 minutes after the initial landing, as the Australian divisional headquarters and the 2/23rd Infantry Battalion were coming ashore, a small force of Japanese aircraft attacked the landing craft carrying the infantry ashore. As a result, two of these craft were heavily damaged and numerous casualties inflicted, including the 2/23rd Battalion’s commanding officer, who was killed when a bomb hit the bridge of LCI-339.

There were more Japanese air attacks during the afternoon, but a force of about 70 Japanese aircraft, operating from bases on New Britain, were beaten off over Finschhafen. Another group achieved success around Morobe as it attacked empty transports which were departing Finschhafen, while off Cape Ward Hunt another group attacked an Allied convoy carrying follow-on forces, including the rest of Whitehead’s 26th Brigade. On LST-471, 43 men were killed and another 30 wounded, and on LST-473 eight men were killed and another 37 wounded. This did not prevent the flow of supplies and the arrival of reinforcements in the shape of Evans’s 24th Brigade on the next day. The Australians then began the physically exhausting advance to the west in the direction of Lae in terrain characterised by thick jungle, swamps, kunai grass and numerous rain-swollen rivers and streams which, along with heavy rain, slowed their progress. On the night of 5/6 September, the Japanese launched an attack on the leading Australian battalion, but were not able to prevent its advance. At this point, the 26th Brigade moved inland to strike toward Lae from the north-east while the 24th Brigade continued the coastal advance.

It was at this point that the 9th Division’s advance was further slowed by a lack of supplies. It was not until 9 September that the Australians reached the Busu river. The 2/28th Battalion was leading the Australian advance at this stage, and the soldiers had to wade through the river. The current was strong, however, and as a result many of the men, of whom 13 were drowned, were swept downstream. Nevertheless, the 2/28th Battalion was able to establish a bridgehead to the west of the river. As heavy rain began again to fall, the river rose once again and prevented other units from crossing. This effectively isolated the single Australian battalion, which then came under repeated attacks. On 14 September, the 26th Brigade was able to force its way across the river, and the advance could be continued. Along the coast the 24th Brigade was held up by a determined Japanese defence in front of the Butibum river, which was the last water obstacle before Lae. The stream was finally forded on 16 September, by which time Lae had fallen to men of the 7th Division.

The other, and indeed more successful, element of the Allied operation to clear the Japanese from the south-eastern and northern coasts of the Huon Gulf, centred on Lae, was that associated with the US airborne assault on Nadzab on 5 September 1943 and subsequent reinforcement of this airhead by an Australian overland advance. From this airhead the Australians advanced to take Lae, for which the Japanese elected not to fight.

The airborne assault was carried out by Colonel Kenneth H. Kinsler’s US 503rd Parachute Infantry and elements of the Australian 2/4th Field Regiment, and the Australian 2/2nd Pioneer Battalion, 2/6th Field Company, and B Company of Papuan Infantry Battalion reached Nadzab after an overland and river trek that same day and began preparing the airfield. The first transport aircraft landed during the next morning, but bad weather then delayed the Allied build-up. Over the next days, the 25th Brigade of the 7th Division gradually arrived.

Once assembled at Nadzab, the 25th Brigade began to advance on Lae. On 11 September it engaged and defeated a Japanese detachment at Jensen’s Plantation, and then engaged and defeated a larger Japanese force at Heath’s Plantation. The Japanese then decided not to fight for Lae, and Salamaua slightly to its south-east on the same coat, and instead withdrew across the Saruwaged range in a gruelling test of endurance for men who had to struggle over the rugged mountains. Men of the 25th Brigade reached Lae shortly before those of the 9th Division advancing on Lae from the opposite direction.

The development of Nadzab as an air base was delayed by the need to upgrade the Markham valley road. This was a difficult task much hampered by wet weather, but the road was opened on 15 December and Nadzab then became the major Allied air base in New Guinea.

The Markham river originates in the Finisterre range and flows for 110 miles (175 km) to debouch into the Huon Gulf near Lae. The Markham river valley, which rises to a height of 1,210 ft (370 m), lies between the Finisterre range to its north and the Bismarck range to its south, and varies from 6 to 12 miles (10.25 to 19.25 km) in width. The valley floor is composed largely of gravel and is generally infertile. In 1943/44 half of its area was covered by dense kangaroo grass 4 to 5 ft (1.2 to 1.5 m) high, but in parts where there had been a build-up of silt, sharp-edged kunai grass grew from 6 to 8 ft (1.8 to 2.5 m) high. About 39 in (1000 mm) of rain falls every year. The Markham valley was traversable by motor vehicles in the dry season between December and April, and in 1943/44 thus constituted part of a natural highway between the Japanese bases at Lae and Madang.

At Blamey’s Advanced Allied Land Forces Headquarters in St Lucia, Queensland, the deputy chief of the general staff, Major General Frank H. Berryman, headed the planning process. A model of the area of Lae and Salamaua was built in a secure, sealed room at St Lucia. On 16 May Blamey held a conference with Berryman and Lieutenant General Sir Edmund Herring, the commander of I Corps, around the model, and the details of the new 'Postern' operation were discussed. Blamey’s operational concept was for a double envelopment of Lae: Wootten’s 9th Division was to land to the east of Lae and advance on Lae, and Vasey’s 7th Division was to advance on Lae from the north-west by an overland route. The primary role envisaged for the 7th Division was to prevent Japanese reinforcement of the Lae area by establishing itself in a blocking position across the Markham river valley, and its secondary role was to assist the 9th Division in the capture of Lae.

Meanwhile, Savige’s 3rd Division in the Wau area and Major General Horace H. Fuller’s US 41st Division around Morobe were ordered to advance on Salamaua in a threat deigned to persuade the Japanese to move forces from Lae. The result was the arduous Salamaua campaign between June and September, and which at times looked like succeeding all too well, capturing Salamaua and forcing the Japanese back to Lae, thereby throwing Blamey’s whole strategy into disarray.

'Postern' called for the 7th Division to move in transports to Port Moresby, in coastal shipping to the mouth of the Lakekamu river, in barges up the river to Bulldog, and in trucks over the road linking Bulldog Road with Wau and Bulolo. From there it would march overland via the Watut and Wampit river valleys to the Markham river, cross this river with the aid of US paratroops, and secure an airfield site. There were a number of suitable airfield sites in the Markham river valley, and of these Blamey selected Nadzab as the most promising.

To Vasey, this plan was a 'dog’s breakfast' with a number of serious problems. It relied on the Bulldog road being completed, which it was not as a result of the rugged nature of the country being traversed and shortages of equipment; even if the road was completed, it was unlikely that the 7th Division could be in position in time for the projected start of the operation; the division had sustained heavy casualties in the Battle of Buna and Gona and was seriously under-strength, with many men on leave or suffering from malaria; and it would take time to concentrate the division at its camp at Ravenshoe, Queensland on the Atherton Tableland. With regard to this last, Brigadier W. E. H. Pascoe’s 1st Motor Brigade was disbanded in July to provide reinforcements, and these reinforcements passed through the Jungle Warfare Training Centre at Canungra, Queensland, where they spent a month training under conditions closely resembling those in New Guinea.

The delays in getting the overland supply route organised and the 7th Division itself ready meant that, in the initial stages of the operation at least, the 7th Division would have to be maintained by air. Vasey further proposed that the bulk of his forces should be freed of the tiring overland march by moving directly to Nadzab by air, which increased the importance of the early capture of Nadzab. MacArthur agreed to make the 2/503rd Parachute Infantry, based at nearby Gordonvale, Queensland, available to New Guinea Force for the capture of Nadzab, and authorised the regiment to conduct training with the 7th Division, with whom a number of exercises were conducted. Eager to discuss the German 'Merkur' airborne landing in the battle for Crete with the 21st Brigade’s commander, Brigadier Ivan Dougherty who had commanded a battalion in that battle, Kinsler of the 503rd Parachute Infantry took the unusual step of parachuting into Ravenshoe. On 31 July, Vasey raised with Kinsler the prospect of utilising the entire US regiment. Blamey took up the matter with MacArthur, who authorised it on 8 August. Blamey made the Australian army transport Duntroon available for the shipment from Cairns to Port Moresby of the regiment less its 2nd Battalion and advance party, which were delivered by air as originally planned.

Major General Ennis C. Whitehead, commander of the Advanced Echelon of Lieutenant General George C. Kenney’s 5th AAF, made five C-47 Dakota transport aircraft available to the 7th Division each day so that the Australian infantrymen could practise loading and unloading. Whitehead also made available a B-17 Flying Fortress heavy bomber so that Vasey could fly low over the target area on 7 August on a personal reconnaissance. Meanwhile the 2/2nd Pioneer Battalion and 2/6th Field Company practised crossing the Laloki river with folding boats before flying to Tsili Tsili airfield on 23/24 August.

To give the paratroops a measure of artillery support, Lieutenant Colonel Alan Blyth of the 2/4th Field Regiment proposed dropping some of its eight short 25-pdr gun/howitzers by parachute. A call was issued for volunteers, and four officers and 30 other ranks were selected. On 30 August, Vasey watched them carry out a practice jump at Rogers Airfield. This turned out to be the easy part. Brand new guns were received from the 10th Advanced Ordnance Depot at Port Moresby on 23 August: two were handed over for training, and the other six were sent the 2/117th Field Workshops for inspection and checking. All six were condemned, owing to a number of serious defects in assembly and manufacture. On 30 August, the gunners received orders to move out the next day, so the 2/51st Light Aid Detachment cannibalised the six condemned guns to produce two working guns, which were proofed by firing 20 rounds per gun. Only one was ready in time to leave with the gunners so the other followed on a special flight. Eight of the 2/4th Field Regiment’s 25-pdr Mk II guns were also condemned after metal filings had been discovered in their buffer systems.

Vasey was concerned about the Japanese strength in the Lae area, which his staff estimated at 6,400 men, in addition to the 7,000 men who, Herring’s I Corps staff estimated, were in the Salamaua area. A more immediate danger, though, was that of the 4th Air Army at Wewak: air reconnaissance photographs revealed 199 Japanese aircraft on Wewak’s four airfields on 13 August. On 17 August, Whitehead’s heavy and medium bombers and fighter-fighters, escorted by fighters, bombed Wewak. Taking the Japanese by surprise, they destroyed about 100 Japanese aircraft on the ground, and by September the Japanese army air force had at its disposal only 60 or 70 operational aircraft to oppose the Allied air forces in New Guinea, although both the 6th Air Division and 7th Air Division were in the area.

On the south bank of the Markham river is Markham Point, where the Japanese maintained a force of about 200 men on commanding ground. Part of the 24th Battalion was ordered to capture the position. The attack on the morning of 4 September went wrong from the start, when two scouts were wounded by a mine. The force fought its way into the Japanese position but took heavy casualties and was forced to withdraw after losing 12 men killed and another six wounded. It was then decided to merely contain the Japanese force at Markham Point, which was subjected to mortar fire and an air attack.

The US transport aircraft were controlled by Prentiss’s 54th Troop Carrier Wing, headquartered at Port Moresby. Prentiss had two groups under his command: Lieutenant Colonel Fred M. Adams’s 374th Troop Carrier Group at Ward’s Field and Colonel Joel G. Pitts’s 375th Troop Carrier Group at Dobodura, as well as the 65th and 66th Troop Carrier Squadrons of Colonel Harry J. Sands’s 403rd Troop Carrier Group at Jackson’s Field. In addition, Prentiss could draw on Colonel Samuel V. Payne’s 317th Troop Carrier Group at Archerfield Airport and RAAF Base Townsville, although it was not under his command. Postponing the operation from August to September 1943 also allowed for the arrival of Colonel Cecil B. Guile’s 433rd Troop Carrier Group from the USA. Each squadron was equipped with 13 C-47 aircraft, and each group consisted of four squadrons, for a total of 52 aircraft per group.

The date for the undertaking was chosen by Kenney on the basis of advice from his two weather-forecasting teams, one Australian and the other American. Under ideal circumstances, the day selected would offer clear conditions from Port Moresby to Nadzab but fog over New Britain, thereby preventing the Japanese air forces at Rabaul from intervening. Forecasting the weather days in advance with such precision was difficult enough in peacetime, but more so in wartime, when many of the areas from which the weather patterns developed were occupied by the Japanese and data from them was consequently denied to the forecasters. When the two teams differed over the best possible date, Kenney split the difference informed MacArthur that the operation would be launched on the morning of 4 September to coincide with the amphibious movement of the 9th Division to Hopoi Beach, and that at about 09.00 of 5 September the 503rd Parachute Regiment would be delivered to Nadzab.

The day of 5 September began with inauspiciously bad weather: fog and rain shrouded both of the departure airfields, Jackson’s and Ward’s, but by 07.30 the fog had started to dissipate, as the forecasters had predicted, and the first C-47 took off at 08.20. The formation of 79 C-47 aircraft, each carrying 19 or 20 paratroopers, was divided into three flights. The first comprised 24 aircraft of the 403rd Troop Carrier Group from Jackson’s, and carried the 1/503rd Parachute Infantry; the second comprised 31 aircraft of the 375th Troop Carrier Group from Ward’s, and carried the 2/503rd Parachute Infantry; and the third comprised 24 aircraft of the 317th Troop Carrier Group from Jackson’s, and carried the 3/503rd Parachute Infantry. Each battalion had its own drop zone. The transports were escorted by 48 P-38 Lightning fighters of Lieutenant Colonel Malcolm A. Moore’s 35th Fighter Group and Prentice’s 475th Fighter Group, 12 P-39 Airacobra fighters of the 36th Fighter Squadron, Lieutenant Colonel Philip H. Greasley’s 8th Fighter Group and 48 P-47 Thunderbolt fighters of Kearby’s 348th Fighter Group.

When Kenney informed MacArthur that he planned to observe the operation from a B-17, MacArthur reminded Kenney of his orders to keep out of combat. Kenney went over the reasons why he thought he should go, and MacArthur then agreed with Kenney so strongly that he too decided to watch the undertaking from the air.

Some 302 aircraft from eight airfields in the Port Moresby and Dobodura areas made rendezvous over Tsili Tsili at 10.07, flying through cloud and mountain passes, and also over the tops of the mountains. Some 48 North American B-25 Mitchell medium bombers of Lieutenant Colonel Brian O’Neill’s 38th Bombardment Group, and Colonel Jared V. Crabb’s led the formation to open the way by dropping their loads of 60 20-lb (9.1-kg) fragmentation bombs and strafing with the eight 0.5-in (12.7-mm) machine guns mounted in their noses. They were followed by seven A-20 attack aircraft of Major Donald P. Hall’s 3rd Bombardment Group (Light), each carrying four M10 smoke tanks under its wing: the smoke tanks were each filled with 19 US gal (22.8 Imp gal; 86.4 litres) of the FS smoke agent. In two groups of two and one of three flying at an altitude of 250 ft (76 m) at 225 mph (362 km/h), these aircraft laid three smoke curtains adjacent to the three drop zones. The leading aeroplane discharged two tanks, waited four seconds and then discharged the other two. The following aircraft went through the same procedure, creating a slight overlap to ensure a continuous screen. The conditions were favourable, and the 85% humidity kept the screens effective for five minutes and stopped their dispersal for 10 minutes.

Next came the C-47 transport aircraft an an altitude of 400 to 500 ft (120 to 150 m) at 100 to 105 mph (161 to 169 km/h). The drop of the paratroopers began at 10.22, and each of the aircraft dropped all of its men in 10 seconds and the whole regiment was unloaded in 4 minutes 30 seconds.

The transport aircraft were followed by five B-17 bombers with their racks carrying not bombs but 300-lb (140-kg) parachute-fitted supply packages to be dropped to the paratroopers on demand. This mobile supply unit remained available for much of the day, eventually dropping 15 tons of supplies.

A group of 24 Consolidated B-24 Liberator and four B-17 heavy bombers departed the column just before the junction of the Watut and Markham rivers, and attacked the Japanese defensive position at Heath’s Plantation, about half-way between Nadzab and Lae. Five B-25 weather aircraft were used along the route and over the passes, to keep the units informed on weather to be encountered during their flights to the rendezvous.

During the operation, including the bombing of Heath’s Plantation, 92 tons of HE and 32 tons of fragmentation bombs were dropped, and 42,580 rounds of 0.5-in (12.7-mm and 5,180 rounds of 0.3-in (7.62-mm) ammunition were fired.

The US aircraft met no air opposition, and only one C-47 failed to make the drop: its cargo door blew off during the flight, damaging an elevator, but the aeroplane returned safely to base. Three paratroopers were killed in the drop: two fell to their deaths when their parachutes malfunctioned, and the third landed in a tree and then fell some 66 ft (20 m) to the ground. There were 33 minor injuries caused by rough landings.

The three battalions met no opposition on the ground and formed up in their assembly areas, a process which took some time as a result of the tropical heat and the high grass.

Five C-47 transport aircraft of the 375th Troop Carrier Group, carrying the men of the 2/4th Field Regiment, lifted off from Ward’s Airfield after the main force had landed at Tsili Tsili and, after one hour on the ground, set out for Nadzab. Most of the men jumped from the first two aircraft, the next three aircraft dropped equipment, including the dismantled guns, and the men who had pushed out the guns and supplies followed when these three aircraft made a second pass over the drop zone. The gunners then had to locate and assemble their guns in the tall grass. Enough parts were found to assemble one gun and have it ready for firing within 150 minutes, although to maintain surprise they did not carry out registration fire until the morning of the following day. It took three days to find the missing parts and assemble the other gun. At 15.15, two B-17 bombers dropped 192 boxes of ammunition. Their dropping was accurate, but some boxes of ammunition tore away from their parachutes.

Meanwhile, Lieutenant Colonel J. T. Lang’s force (2/2nd Pioneer Battalion, 2/6th Field Company, and detachments from the 7th Division Signals, 2/5th Field Ambulance and Australian New Guinea Administrative Unit, with 760 native carriers) departed from Tsili Tsili on 2 September. Most of the force moved overland, reaching Kirkland’s Crossing on 4 September to rendezvous with B Company of the Papuan Infantry Battalion. That night, a party of engineers and pioneers set out from Tsili Tsili in 20 small craft and moved down the Watut and Markham rivers to join Lang’s force at Kirkland’s Crossing. The small riverine task force included 10 British 5-ton folding assault boats and Australian-built Folbots (folding kayaks), which met the 2/6th Independent Company, whose men had reconnoitred the proposed crossing area in eight Folbots on the previous day. While both rivers were shallow, they were also fast-flowing and littered with shoals and hidden snags. Three boats had been lost, together with the equipment they were carrying, and one man had been drowned. On the morning of 5 September, Lang’s force reached the point at which the Markham river forms three arms separated from each other by wide sand bars. Two were fordable but the third was deep and also flowing at 5 kt. Using the folding boats and local timber, the commandos constructed a pontoon bridge, allowing the whole force to cross the river safely with all their equipment. That evening, the Australians reached the US position at Nadzab.

On the following day the Australian and US force went to work on the airstrip with hand tools, felling trees, filling potholes and erecting a windsock. A force of 14 gliders was supposed to fly in three light tractors, three mowers, a wheeled rake and other engineering equipment from Dobodura. However, in the absence of any opposition, immediate resupply was not urgent, and because he had doubts about the proficiency of the glider pilots, whom he knew had undergone only minimal training, Blamey cancelled the glider operation on the grounds that it was not worth the risk to the glider pilots or their passengers. Instead, an afternoon supply run was made by specially modified B-17 bombers. In the absence of mowers, the kunai grass was cut by hand and burned, causing the destruction of some stores and equipment which had been lost in the long grass. By 11.00 on 6 September, the original 1,500-ft (460-m) airstrip, which had not been used for more than one year, had been extended to a length of 3,300 ft (1000 m).

The first aeroplane to land, at 09.40 on 6 September, was an Piper L-4 liaison machine carrying Colonel Murray C. Woodbury, commander of the US Army’s 871st Airborne Engineer Aviation Battalion. Three transports followed, nearly running down some of the men still working on the strip. Another 40 aircraft followed in the afternoon, many containing US and Australian engineers.The 871st Battalion followed on the next day with its small air-portable bulldozers and graders. The Americans located a site for a new airstrip, which became known as No. 1, the existing one becoming No. 2. The site proved to be excellent, inasmuch as it was an old, dry riverbed with a largely gravel bottom. A gravel base and steel planking was laid to accommodate the fighters based at Tsili Tsili as these were in danger of bogging down when the weather deteriorated.

While engineers and anti-aircraft gunners arrived from Tsili Tsili, no infantry arrived from Port Moresby on 6 September as a result of bad flying weather over the Owen Stanley range, although the 2/25th Battalion was flown to Tsili Tsili. On 7 September the 2/33rd Battalion boarded trucks of the 158th General Transport Company that took it to marshalling areas near the airfields in preparation for the movement to Nadzab. At 04.20 a B-24 of Colonel Harry J. Hawthorne’s 43rd Bombardment Group left Jackson’s Field on a reconnaissance sortie to Rabaul, with a full load of fuel and four 500-lb (227-kg) bombs, but clipped a tree at the end of the runway, crashed into two other trees and exploded, killing all 11 crewmen on board and spraying burning fuel over a large area. Five of the 158th General Transport Company’s trucks containing men of the 2/33rd Battalion were hit and burst into flames. Every man in those trucks was killed or injured: 15 were killed outright, 44 died of their wounds, and 92 were injured but survived. Despite the disaster, the 2/33rd Battalion flew to Tsili Tsili as scheduled.

As a result of the weather’s unpredictability, aircraft continued to arrive at Nadzab on only a sporadic basis. Only the 2/25th Battalion and part of the 2/33rd Battalion had reached Nadzab by the morning of 8 September, when Vasey ordered the commander of the 25th Brigade, Brigadier Kenneth W. Eather, to begin the advance on Lae. That day there were 112 landings at Nadzab. On 9 September, as the advance began, the rest of the 2/33rd Battalion reached Nadzab from Tsili Tsili, but while there were 116 landings at Nadzab, bad weather prevented the 2/31st Battalion from leaving Port Moresby. Finally, on 12 September, after three non-flying days, the 2/31st Battalion reached Nadzab in some of the 130 landings on the two strips at Nadzab during that day.

On 13 September, a platoon of the 2/25th Battalion came under very heavy fire from a concealed Japanese machine gun near Heath’s Plantation. This fire wounded a number of Australians and halted the platoon’s advance until one man on his own initiative dashed toward the post and hurled two grenades, killing some but not all of the Japanese. The man next rushed back to his section, seized a Bren light machine gun, dashed back to the Japanese post and silenced it, and then asked permission to go out again to rescue a wounded man, which he accomplished successfully under heavy fire from another Japanese position.

To the north of the main advance, a patrol of Lieutenant Colonel John J. Tolson’s 3/503rd Parachute Infantry encountered a force of 200 Japanese crossing the Bumbu river on 15 September, and reported the infliction of heavy losses on the Japanese. The arrival during this day of the first units of Dougherty’s 21st Brigade at Nadzab at last allowed the paratroopers to be relieved.

By this time, the 9th Division was about 1.5 miles (2.4 km) to the east of Lae, while the 7th Division was 7 miles (11 km) distant to the north-west, and it seemed that the nearer formation would reach Lae first.

The 7th Division resumed its advance at dawn on 16 September. The last 10 Japanese facing the 2/33rd Battalion were killed and the 2/25th Battalion passed through the 2/33rd Battalion’s position and headed for Lae. As the battalion moved along the Markham valley road, it encountered a few sick Japanese soldiers who checked the column momentarily. Eather came up in his Jeep and urged his men to speed their progress and then, armed with a pistol, took the point position with his men following. The column entered Lae unopposed by the Japanese, but 5th AAF aircraft strafed the 2/33rd Battalion and dropped parachute fragmentation bombs, wounding two men. By a time early in the afternoon, the 2/31st Battalion had reached Lae airfield, where it killed 15 Japanese and captured one. The 25th Brigade then came under 'friendly fire' from the 9th Division’s 25-pdr artillery, which wounded one man. Vasey and Eather tried every available means to inform Wootten of the situation, and at 14.25 the 9th Division’s guns ceased firing.

The so-called Battle of Kaiapit was another action of the Markham and Ramu Valley and Finisterre Range campaign. After the landings at Nadzab and Lae, the Allies attempted to exploit their success with an advance into the upper Markham valley, beginning with Kaiapit, which the Japanese planned to use as a means of threatening the Allied position at Nadzab, and and of creating a diversion to provide the Japanese garrison at Lae time to escape.

Following the Nadzab landing, Blamey intended to exploit this successful undertaking with an advance into the upper part of the Markham river valley, a move which would shield Nadzab from Japanese ground attack, and serve as a jumping off point for an overland advance into the Ramu river valley to capture more airfield sites. On 16 September, the day on Lae fell to the Allies, Herring, Vasey and Whitehead met at the last’s headquarters. Whitehead wanted fighter airstrips established in the Kaiapit area by 1 November so that short-range fighters could be based within range of the major Japanese bastion at Wewak. The 7th Division’s task was to prevent the Japanese at Madang from using the Markham and Ramu river valleys to threaten Lae or Nadzab. Vasey and Herring considered both an overland operation to capture Dumpu, and an airborne operation using paratroopers of the US Army’s 503rd PIR. Blamey did not approve the concept of taking Dumpu as a first step toward the objective, and demanded the initial seizure of Kaiapit.

Until a road from Lae could be opened, the Kaiapit area could be supplied only by air and there were a limited number of transport aircraft. Even flying in an airborne engineer battalion to improve the airstrip would have involved taking aircraft away from operations supporting the 7th Division at Nadzab. Moreover, Whitehead warned that he could not guarantee adequate air support for both Kaiapit and the imminent Finschhafen operation at the same time. However, Herring calculated that the 7th Division had sufficient reserves at Nadzab to allow maintenance flights to be suspended for a week or so after the capture of Kaiapit, and planned to seize Kaiapit with an overland advance from Nadzab by independent companies, the Papuan Infantry Battalion, and the 7th Division’s 21st Brigade.

An aerial reconnaissance of the airstrip at Kaiapit was flown on 11 September by No. 4 Squadron of the RAAF, and this indicated that the airstrip appeared to be in good condition, with the kunai grass recently cut. The USAAF’s Lieutenant Everette E. Frazier selected a burned-off area near the Leron river, not far from Kaiapit, to land in an Piper L-4 light aeroplane, and reported that it was feasible to land C-47 aircraft there. On 16 September, Colonel W. Hutchison of the USAAF, the local air commander, approved the site for Dakota operations.

The 2/6th Independent Company had reached Port Moresby from Australia on 2 August, and its commander, Captain Gordon King, received a warning order on 12 September alerting him to prepare for the capture of Kaiapit. At this time, an independent company possessed a nominal strength of 20 officers and 275 other ranks. Larger than a conventional infantry company, it was organised into three platoons, each of three sections, each of which comprised two subsections. It had considerable firepower: each sub-section had a 0.303-in (7.7-mm) Bren light machine gun; the gunner’s two assistants carried rifles and extra 30-round Bren gun magazines; the sniper also carried a rifle, as did one man equipped with rifle grenades; the other four or five men carried Owen sub-machine guns; and each platoon also had a section of 2-in (51-mm) light mortars. The company was self-supporting, with its own engineer, signals, transport, and quartermaster sections.

For three days in a row, the 2/6th Independent Company’s departure from Port Moresby by air was stymied by bad weather before, on 17 September, 13 Dakota transports of the US 374th Troop Carrier Group finally lifted off for Leron. King flew in the leading aeroplane, and as this came in to land King spotted patrols from the Papuan Infantry Battalion in the area. One of the Dakota aircraft blew a tyre as it touched down. Another tried to land on one wheel, but its landing gear collapsed and the machine landed on its belly. The former was subsequently salvaged, but the latter was a total loss. King immediately despatched patrols which soon established contact Captain J. A. Chalk’s B Company, Papuan Infantry Battalion, and during the evening Chalk and King received airdropped messages from Vasey instructing them to occupy Kaiapit with all possible speed and ready a landing strip for troop-carrying aircraft. Vasey informed them that only small Japanese parties that had escaped from Lae were in the area, and their morale was very low.

In fact the Japanese local commander, Major General Masutaro Nakai, commanding the 20th Division's infantry group, had ordered a sizeable force to move to Kaiapit under the command of Major Tsuneo Yonekura Tsuneo. This 500-man force included the 9th and 10th Companies of the 78th Regiment, the 5th Company of the 80th Regiment, one heavy machine gun section, a signals section and an engineer company. From Kaiapit it was to threaten the Allied position at Nadzab, creating a diversion to allow the Japanese garrison at Lae time to escape. The main body left Yokopi in the Finisterre mountain range on 6 September, but was delayed by heavy rains that forced the troops to move, soaking wet, through muddy water for much of the way. Only the advance party of this force had reached Kaiapit by 18 September, by which time Lae had already fallen. Yonekura’s main body, moving by night to avoid being sighted by Allied aircraft, was by this time no further from Kaiapit than King’s men, but was still faced by the need to cross two rivers. Since both sides had the same objective, a clash was now inevitable.

King concentrated the bulk of his men at Sangan, about 10 miles (16 km) to the south of Kaiapit, though one section under Lieutenant E. F. Maxwell, had been sent ahead to scout the village. On the morning of 19 September, King set out for Kaiapit, leaving behind his quartermaster, transport and engineering sections, which would move the stores left behind at the Leron river first to Sangan and then to Kaiapit on the following day. He took one section of Papuans with him, leaving Chalk and the rest of his men to escort the local bearers bringing up the stores.

King’s men walked for 50 minutes at a time and then rested for 10 minutes. The going was relatively easy as the ground was fairly flat, but the kunai gras was 6.5 ft (2 m) tall and trapped both the heat and the humidity, and the Australians were carrying heavy loads of ammunition. The company reached Ragitumkiap, a village close to Kaiapit, at 14.45. While his men had a brief rest, King attempted without success to contact Vasey in Nadzab. Hearing gun fire in the distance, he surmised that Maxwell’s section had been discovered.

The 2/6th Independent Company formed up at 15.15 in kunai grass about 1,300 yards (1185 m) from Kaiapit. As it moved forward, the company came under fire from foxholes on the edge of the village. A 2-in mortar killed a light machine gun position, and the Australians outflanked and then took the foxholes with hand grenades and bayonets. The Japanese withdrew, leaving 30 dead. The Australians suffered two men killed and seven wounded, that latter including King.

The company now established a defensive position for the night, and as thus was under way Lieutenant D. B. Stuart, commander of one of the Papuan platoons, arrived with the information that the battalion had become worried by the loss of radio contact with the independent company and he had been sent to find out what was happening. King ordered Stuart to bring the Papuans up from Sangan with extra ammunition and a more useful radio set. At around 17.30, a Papuan arrived with a message for the Japanese commander: the message had been taken from the latter, who had then been shot as he sought to escape. Ignorant of the fact that it now lay in Australian hands, a Japanese patrol later returned to Kaiapit, and its men were killed when they stumbled across a Bren gun position. Four more Japanese soldiers returned this after, and only one escaped.

The Japanese main party reached Kaiapit after an exhausting night march: Yonekura knew by then that the Australians had reached Kaiapit, but his main concern was not to be caught in the open by Allied aircraft. Spotting Australian positions in the pre-dawn light, the Japanese column opened a heavy fire on the Australians, who replied only intermittently as they wished to conserve their ammunition. Although he was running short of ammunition, King launched an immediate counterattack on the Japanese and took them by tactical surprise.

Having set out at about 06.15 to cover the distance of about 200 yards (180 m) and reach the edge of Village No. 3, Lieutenant Derrick Watson’s C Platoon was pinned down by heavy Japanese fire. King then sent Captain Gordon Blainey’s A Platoon around the right flank, toward the high ground on Mission Hill which overlooked the firefight, and secured this by 07.30. Meanwhile some of the company’s signallers and headquarters personnel gathered as much ammunition as they could, and delivered this to C Platoon at around 07.00. The men of C Platoon then fixed bayonets and continued their advance.

The commander of No. 9 Section of C Platoon, Lieutenant Bob Balderstone led his men in a 70-yard (65-m) advance across open ground and attacked three Japanese machine gun positions with hand grenades. Lieutenant Reg Hallion led his No. 3 Section of A Platoon against the Japanese positions at the base of Mission Hill, and while he was killed in an attack on a machine gun, his section took the position and killed 12 Japanese. By 10:00. the action was over.

After the action, King’s men counted 214 Japanese bodies, and estimated that another 50 or more lay dead in the tall grass. Yonekura was one of the dead. The Australians suffered the loss of 14 men killed and 23 wounded. Equipment abandoned by the Japanese included 19 machine guns, 150 rifles, six grenade throwers and 12 swords.

The 2/6th Independent Company now had 23 wounded and was very short of ammunition. Frazier landed on the newly captured airstrip in his L-4 at 12.30, rejected the airstrip as unsuitable for Dakota operations, and oversaw the preparation of a new airstrip on better ground near Mission Hill. This was still a difficult approach, as aircraft had to land upwind while avoiding Mission Hill. Although it was not known if the airstrip would be ready, Hutchison flew in for a test landing at 15.30 on the following day, 21 September. He collected the wounded and flew them to Nadzab, and returned an hour later with a load of rations and ammunition. He also brought with him Dougherty, commander of the 21st Brigade, and his headquarters, to assume command of the area. At about 18.00, six more transports arrived.

Vasey was concerned for the security of the Kaiapit area as he believed that the Japanese were inclined to continue with a plan once it had been set into motion. Taking advantage of good flying weather on 22 September, 99 round trips were made between Nadzab and Kaiapit, where the bulk of the 2/16th Battalion and some US engineers were landed. The 2/14th Battalion and a battery of the 2/4th Field Regiment arrived on 25 September, and Eather’s 25th Brigade began to arrive two days later, freeing Dougherty’s men to advance on Dumpu.

However, Kaiapit did not become an important air base as by the time engineering surveys of the area had been completed, Dougherty’s men had captured Gusap. Here the engineers found a well-drained area with soil conditions eminently suitable for the construction of all-weather airstrips, an unobstructed air approach and a pleasant climate. It was therefore decided to limit construction at the swampy and malarial Kaiapit and concentrate on Gusap, where the US 871st, 872nd and 875th Airborne Aviation Engineer Battalions constructed 10 airstrips and associated facilities. The first P-40 Kittyhawk fighter squadron became operational at Gusap in November and an all-weather fighter runway was completed in January 1944.

In overall terms, the 2/6th Independent Company had beaten the vanguard of Nakai’s force and stopped his unit’s advance down the Markham river valley. At the same time, the Battle of Kaiapit had accomplished Vasey’s primary task, for the Japanese could no longer threaten Nadzab, and also opened the way to the Ramu river valley for the 21st Brigade, provided new forward fighter airstrips for the air war against the Japanese, and fully validated the Australian army’s new training methods and the organisational emphasis on firepower.

The fighting for Lae had cost the Japanese more than 2,200 men killed in each part of the operation to take Lae, whereas the Australian casualties had been considerably lighter. The 9th Division lost just 77 men killed and 73 missing. So far as Allied casualties in the Nadzab operation were concerned, the 503rd PIR had lost three men killed and 33 injured in the jump. Another eight had been killed and 12 wounded in action against the Japanese, and 26 had been evacuated sick. Between 5 and 19 September, the 7th Division reported 38 killed and 104 wounded, while another 138 had been evacuated sick; to this must be added the 11 Americans and 59 Australians killed and 92 Australians injured in the air crash at Jackson’s Field.

Despite their loss of Salamaua and Lae, the Japanese had nonetheless mounted a creditable defence, which had slowed the Allied advance and also allowed the bulk of the Japanese forces in the vicinity to get away, withdrawing to the north across the Huon peninsula to continue the fight.

Crossing the Saruwaged range of the Huon peninsula proved to be the harshest of endurance tests for the Japanese. They started out with rations for 10 days, but had exhausted these by the time they reached Mt Salawaket. The 51st Division had already abandoned most of its heavy equipment, and the men were in such desperate straits that they now started to discard their personal weapons in conditions of great cold near the mountain tops, where there were also strong winds and even snow. Even after the men had started down toward the coast, there were precipitous drops and many men fell to their deaths as 'Postern' drew to a close.

The subsequent development of Nadzab was wholly dependent on heavy construction equipment landed at Lae and moved up the Markham valley road. The job of improving the road was assigned to the 842nd Engineer Aviation Battalion, which arrived at Lae on 20 September, but after a few days this unit was ordered to relieve the 871st Airborne Aviation Battalion at Nadzab, which it reached on 4 October. Then a combination of unseasonable rainfall and heavy military traffic destroyed the road surface and closed the road, forcing Nadzab to be supplied from Lae by air. The 842nd Battalion then had to resume work on the road, this time from the Nadzab end. Heavy rain was experienced on 46 of the next 60 days, but the road was reopened on 15 December, allowing the 836th, 839th, 868th and 1881st Engineer Aviation Battalions and No. 62 Works Wing, RAAF, to move to Nadzab to work on the development of the air base.

This eventually comprised four all-weather airfields. No 1 had one runway 6,000 ft (1830 m) long and 100 ft (30.5 m) wide surfaced with Marsden Matting, and another runway 7,000 ft (2135 m) long and 100 ft (30.5 m) wide surfaced with bitumen. No. 2 had a runway 4,000 ft (1220 m) long and 100 ft (30.5 m) wide partially surfaced with bitumen. No. 3 had a runway 7,000 ft (2135 m) long and 100 ft (30.5 m) wide surfaced with bitumen in the centre with 1,000 ft (305 m) of Marsden Matting at each end. No. 4 was the RAAF airfield and had a pair of parallel runways each 6,000 ft (1830 m) long and 100 ft (30.5 m) wide surfaced with bitumen.

While the capture of Lae had clearly been an Allied victory, achieved more quickly and at lower cost than had been anticipated, a significant proportion of the Japanese garrison had nevertheless escaped across the Saruwaged range and would have to be fought again in the Huon peninsula campaign which ended with 'Dayton'.

Salamaua was not developed as a base. Herring, the commander of the Australian I Corps, visited Salamaua by PT-boat on 14 September 1943, three days after its capture, and found little more than bomb craters and corrugated iron. He recommended cancelling the development of Salamaua and concentrating all available resources on Lae. The base which had originally been envisaged now seemed to represent a probable waste of effort as Salamaua was a poor site for a port or air base. However, in drawing the Japanese attention away from Lae at a critical time, the assault on Salamaua had already served its purpose.

Lae was transformed into two bases: the Australian Lae Base Sub Area and the US Base E. Herring combined the two as the Lae Fortress, under Milford’s command. As Blamey had ordered the launch of 'Postern' before the logistical preparations had been completed, most of the units needed to operate the base were not yet available. Even so, Lae’s importance rested in the fact that its port supplied the air base at Nadzab, but this was compromised, in the short term at least, by the fact that the Markham valley road was in poor condition. In order to expedite the development of Nadzab, minimal efforts were made to repair it, and only heavy military traffic bound for Nadzab was permitted to use it. The road was closed following heavy rains on 7 October and did not reopen until December. Until then, Nadzab had to be supplied by air, and its development was slow because heavy engineer units could not get through.

The impact of the loss of Salamaua and Lae had great significance for the Japanese, with ramifications extending well outside the New Guinea theatre. While the Imperial General Headquarters had regarded the defeats in the Guadalcanal campaign and the battle of Buna and Gona as setbacks, albeit important setbacks, it had nonetheless continued to plan offensives in the South-West Pacific. Now it concluded that the Japanese position in this sector of the Japanese defensive perimeter was over-extended, and drew a new defensive line running through western New Guinea, the Caroline islands group and the Mariana islands group, with all positions beyond that line to be held as an outpost line. Imamura was now charged not with winning a decisive victory, but only with holding on as long as possible in order to delay the Allied advance.