Otherwise known as the 'Landing on Scarlet Beach', the Australian 'Diminish' landing against the Japanese in eastern New Guinea was the first step in the 'Campaign for the Huon Peninsula' (22 September/2 October 1943).

In this undertaking, one Australian brigade was landed at Scarlet beach, to the north of Siki Cove and south of the Song river, to the east of Katika and about 6.2 miles (10 km) to the north of Finschhafen. The earliest possible capture of Finschhafen was desired as it would allow the construction of air base and naval facilities to assist Allied air and naval forces to conduct operations against the Japanese bases in New Guinea and New Britain.

After Lae had fallen at a time earlier than they had anticipated, the Allies were quick to exploit the advantage. As a result of faulty intelligence, which underestimated the size of the Japanese force in the area, the assault force chosen consisted of only Brigadier W. J. V. Windeyer’s Australian 20^th Brigade of Major General G. F. Wootten’s Australian 9^th Division. The landing at Scarlet beach on 22 September 1943 was the first opposed amphibious landing that Australian forces had made since the Landing at Anzac Cove in the Gallipoli campaign of 1915. Navigational errors resulted in the troops being landed on the wrong beach, with some of them coming ashore at Siki Cove and taking heavy fire from the strong Japanese defences in pillboxes. After reorganising, the Australians pushed inland. The Japanese put up stiff resistance on the high ground at Katika, but were forced back. By the end of the day, the Australians had secured their objectives. The Japanese launched a retaliatory air raid on the ships of Ear Admiral Daniel E. Barbey’s US 7^th Amphibious Force, but US fighter aircraft defended the convoy and no ships were hit. Continued Japanese air attacks on the beach-head inflicted numerous casualties over the course of the battle.

During the planning for what developed as the 'Campaign for the Huon Peninsula', the Allies identified three areas as key and decisive terrain in the area: the beach to the north of Katika, which was later named Scarlet by the Allies, the 3,150-ft (960-m) peak called Sattelberg 5 miles (8 km) to the south-west and which dominated the area, and Finschhafen as this possessed a small airfield and occupied a point on the coast in a bay which offered protected harbour facilities. Before the war, the town had a population of about 30 white and 60 native people. There were good anchorages for vessels of up to 5,000 tons in Dreger Harbour, Langemak Bay and Finsch Harbour, and the flat coastal strip provided a number of potential airfield sites.

Allied estimates of the number of Japanese troops in the Finschhafen area varied very considerably. Brigadier General Charles A. Willoughby, the assistant chief-of-staff, and therefore the head of the intelligence branch at General Douglas MacArthur’s general headquarters, considered Finschhafen to be primarily a trans-shipment point, and the troops there to be mainly from line of communication units. The fall of Lae ended its utility, so Willoughby reduced his estimate of the number of Japanese troops in the area to 350. Based on this appreciation, the general headquarters believed that Finschhafen would be a 'pushover'.

There was reason to believe otherwise, however. A 10-man Allied Intelligence Bureau patrol of three Australian officers, one US amphibian scout of the US Army’s 532^nd Engineer Boat and Shore Regiment, one signaller from 'Z' Special Unit and five native soldiers, was landed during the night of 11/12 September in rubber boats launched from two PT-boats. The scouts were unable to obtain the hydrographic information they sought as there were Japanese patrols in the area. Several machine gun positions were identified during the reconnaissance before the men of the patrol were extracted on 14 September.

As had happened during the 'Campaign of the Kokoda Track' and the 'Battle of Buna and Gona', estimates by Australian intelligence differed greatly from those of the general headquarters, as they were based on a different methodology. The intelligence staff at General Sir George Blamey’s Allied Land Forces Headquarters, headed by Brigadier J. D. Rogers, believed that there was a much higher figure of some 3,000 men. Lieutenant General Sir Edmund Herring’s I Corps produced an estimate of 1,800 men. The Allies' best source of intelligence, 'Ultra' offered nothing on the matter: Finschhafen had been mentioned in only five decrypted messages in the previous three months, and most of these were in the insecure Japanese Water Transport Code. Only after the capture of Japanese codebooks in the 'Battle of Sio' in January 1944 were the Allies able to systematically break into the Japanese army codes. In fact, Japanese strength in the area on 22 September was about 5,000 men.

Two contingency plans had been prepared by Herring’s Australian I Corps. One was a ship-to-shore operation by the 16^th Brigade or 7^th Brigade of Major General J. E. S. Stevens’s Australian 6^th Division, a militia formation at Milne Bay, and the other was for a shore-to-shore operation by a brigade of Wootten’s Australian 9^th Division. The operation was codenamed 'Diminish', which was in fact that of Finschhafen itself. In the plan produced by the I Corps on 24 August 1943, Herring selected beaches immediately to the south of the Song river for the landing as the indications were that it was suitable for landing craft. Most of the Japanese defenders and defences were believed to be facing to the south in anticipation of an Australian overland advance from Lae. The landing in this area avoided the need to cross the Mape river, which was believed to be a significant obstacle. The landing area became known as Scarlet beach from the post-landing red screens and lights used to guide landing craft: the left-hand end of the beach was marked with a solid red panel mounted on tent poles, and its right-hand end with a panel of alternating red and white. At night, the left-hand panel would have a red light, and the right-hand panel alternating red and white. This scheme had first been used at Red beach during the landing at Lae, and to avoid the possible confusion of having two Red beaches, the new landing beach was named Scarlet beach.

On 16 September, the day on which Lae fell, MacArthur ordered that Finschhafen be captured as soon as possible, and on the following day chaired a conference at Port Moresby. He and Blamey selected the second contingency, a landing by a brigade of the Australian 9^th Division, whose 20^th Brigade was selected as it was still relatively fresh, and had experience with amphibious operations from the landing at Lae. The Australian 6^th Division’s movement to New Guinea was postponed. Commanding the 7^th Amphibious Force, Barbey had originally counted on a four-week gap between the fall of Lae and the Finschhafen operation, but on 9 September had told Herring that it would require a minimum of 10 days. Under pressure from MacArthur, however, Barbey cut that to three days. This was too soon for Herring to get the troops together, so 21 September was selected as the target date, and Herring briefed Windeyer on the operation on 18 September. Windeyer felt that the schedule was still too tight, and it was postponed one more day to 22 September.

As at Lae, the first wave, consisting of two companies each from the 2/13^th and 2/7^th Battalions, would land in plywood LCP(R)s launched by the US destroyer transports Brooks, Gilmer, Humphreys and Sands. The rest of the assault force would land in six LST, 15 LCI and six LCT vessels of the 7^th Amphibious Force, and 10 LCM and 15 LCVP craft of the 532^nd Engineer Boat and Shore Regiment. The assault force totalled some 5,300 men. The Australian 9^th Division would be limited to taking 15 days' supplies. One of the lessons of the Lae operation was the need for a naval beach party to take soundings, mark the beaches and channels, and handle communications between ship and shore. US Navy doctrine held that these should be composed of personnel drawn from the attack transports, but none were involved in the Lae or Finschhafen operations. For Finschhafen, an eight-man Royal Australian Navy Beach Party was organised under Lieutenant Commander J. M. Band.

A set of oblique aerial photographs of Scarlet beach was taken on 19 September by the USAAF’s 8^th Photo Reconnaissance Squadron, the only unit in the South-West Pacific Area with the equipment to take such images, and these showed that there was a shallow sand bar along the southern half of the beach, rendering it unsuitable for landing craft. This left beaching space for only three LSTs, so the landing plan was therefore changed so only three of the six LSTs would beach with the initial assault, the other three returning to Buna, and arriving on the beach at 23.00 that night. Herring considered that spreading the LST arrivals might make unloading easier. Wootten noted that this would mean that one battery of 25-pdr gun/howitzers, one light anti-aircraft battery, one quarter of the engineer stores, and the casualty clearing station would have to arrive with the second group. Ironically, soundings taken by the beach party after the landing revealed that the supposed sand bar was actually a white shingle bottom, and in fact the beach was ideally suited to LST operations.

The main point of disagreement between Herring and Barbey concerned the timing of the landing. Barbey and the commander of the 7^th Fleet responsible for naval operations in the South-West Pacific Area, Vice Admiral Arthur S. Carpender, wished that there be no repetition of what had happened at Lae when two LCIs had been lost and two LSTs badly damaged. Although the USAAF and RAAF attacked Japanese air bases in New Britain, this did not stop nine Japanese bombers and 10 fighters attacking Nadzab on 20 September. Moreover, some 23 Japanese warships were sighted in the harbour at Rabaul, and there were reports of Japanese submarines in the area. Accordingly, Barbey proposed landing at 02.00 under a quarter moon, which would allow his ships to unload and get away soon after dawn. Noting that it was the rainy season, and the sky would therefore likely be overcast, Herring doubted that the 7^th Amphibious Force would be able to locate the beach, and pressed for a dawn landing at 05.15. In the end, a compromise was reached and the landing was fixed for 04.45.

APc-15, a small coastal minesweeper of the US Navy, produced 140 mimeographed copies of the 7^th Amphibious Force’s operation order, and these were distributed by PT-boat before she departed for G Beach, 14 miles (23 km) to the east of Lae. During the night, a Japanese raid on Buna sank an LCS(S), and damaged a dock and two merchant ships; nine people were killed and 27 wounded. The US LCI-31 developed engine trouble, and was forced to return to Buna. This left A Company of the 2/13^th Battalion without its transport. The battalion’s commanding officer, Lieutenant Colonel G. E. Colvin, arranged for his men to travel on the US LCI-337, LCI-338 and LCI-342. At about sunset, six Mitsubishi Ki-21 'Sally' twin-engined medium bombers attacked the escorting destroyers, but scored no hits.

The ships arrived off Scarlet beach on time, and the destroyers conducted a short 11-minute preliminary bombardment, although it seems doubtful that any Japanese positions were hit or any casualties inflicted. Low cloud trapped the smoke and dust produced by the bombardment. Scarlet beach and Siki Cove were covered by log-built pillboxes spaced about 50 yards (46 m) apart and connected by shallow trenches, and these were manned by about 300 Japanese defenders. Japanese tracer fire started pouring from the shore.

Almost all the first wave’s LCP(R) craft veered off course to the left, landing between Siki Creek and the rocks of the headland between Siki Cove and Arndt Point. All but one of the craft landed successfully, the exception being that carrying No. 11 Platoon of the 2/15^th Battalion, which had broken down and was towed by the LCP(R) carrying No. 10 Platoon, delaying both. Another LCP(R) appeared and took the platoon in. But only three of the 16 such craft came ashore on Scarlet beach. In some ways this was useful as it meant that the plywood landing craft were not subjected to intense machine gun fire, which might have caused heavy casualties, but nonetheless there were still serious disadvantages to landing on the wrong beach. On the right, Captain T. C. Sheldon’s B Company of the 2/17^th Battalion, accompanied by the anti-tank platoon and No. 10 Platoon of the Papuan Infantry Battalion, landed roughly where intended and then pushed to its objective, North Hill.

The rest of the first wave was jumbled. Major P. H. Pike found his A Company of the 2/17^th Battalion intermingled with Captain P. Deschamps’s B Company of the 2/13^th Battalion. Since the latter had farther to travel, and there was no Japanese opposition, Pike agreed to hold his company back while Deschamps’s men moved toward their objective. Pike then moved his men inland 100 yards (91 m) and waited for daylight. C Company’s task was to seize Arndt Point, but part of C Company was already there, facing a steep cliff. The only unit to encounter serious opposition was Lieutenant C. Huggett’s platoon, which had veered off to the right, and landed on Scarlet beach near the mouth of the Song river, where it came under fire from two Japanese machine gun positions. With the help of a US amphibian scout, Lieutenant Herman A. Koeln, Huggett attacked the posts with grenades and small arms. Another amphibian scout, Lieutenant Edward K. Hammer, encountered a party of Japanese and fired on it. Koeln and Hammer were conspicuous because they were carrying the 10-ft (3.05-m) red canvas signs to mark the beach. The beachmaster, Lieutenant Commander John M. Band, was fatally wounded making his way to Scarlet beach.

The second wave came in LCIs, which had no ramps and their embarked infantry had therefore to disembark over gangways. That they were not suitable for an assault landing had not been overlooked, but they were used as they were all that was available. The first wave’s mission had been to capture Scarlet beach and the foreshore. Since that had not been done, the LCIs came under fire from the Japanese bunkers and, despite explicit orders not to do so, replied with their Oerlikon 20-mm cannon. Some of this fire helped to suppress the Japanese machine guns, while others fired wildly and caused casualties among the Australian troops ashore. Like the first wave, the LCIs had veered off to the left, adding to the chaos, and at least three of the LCIs grounded on a sand bar, but were able to pull back and make better landings, although still on the wrong beach.

The military landing officer, Major J. R. Broadbent, came ashore with the first wave in the same LCP(R) as Pike. With him was an amphibian scout carrying the red signal light that was to mark the centre of the beach for later waves. They were unable to reach the correct location in time for the second wave, but were able to place the signal light and switch it on in time for the third, so it was the first to land on Scarlet beach. Although the first wave had landed seven minutes late, the second was 15 minutes and the third 30 minutes behind schedule. In the confusion, two LCIs collided, killing two soldiers and injuring eight. Some of the LCI captains were reluctant to drive their vessels in hard enough, and many troops disembarked into water that was over their heads. The third wave found the Japanese bunkers still manned, and assaulted them. Most of the Japanese defenders withdrew rather than fight to the finish.

Four LCM craft of Lieutenant Colonel E. D. Brockett’s Boat Battalion of the US 532^nd Engineer Boat and Shore Regiment carrying Bofors 40-mm guns were supposed to arrive with the second wave, but as a result of navigational difficulties were an hour late sand arrived with the six LCM and four LCVP craft of the fourth wave, which was itself 40 minutes late, arriving at 06.10. The 11 LCVP craft of the fifth wave reached the Scarlet beach 10 minutes later. By 06.30, the beach and the foreshore were clear of Japanese, and the destroyer transports and LCIs were on their way back to Buna as the amphibian engineers set up a portable surgical hospital to treat the wounded. Windeyer and his brigade major arrived in a landing craft from the US destroyer Conyngham, and Windeyer established his headquarters in a kunai patch 200 yards (185 m) from the beach. A Japanese soldier threw a hand grenade, which killed one man and wounded the brigade intelligence officer, before himself being killed by sub-machine gun fire.

The sixth and final wave comprising three US tank landing ships (LST-18, LST-168 and LST-204). These had been ordered to wait until the smaller craft had cleared the beach, and beached at 06.50. Each carried an unloading party of 100 men, drawn from the 2/23^rd Battalion, 2/48^th Battalion and 2/2^nd Machine Gun Battalion, who would return with the LSTs. Unloading proceeded speedily, and all the cargo had been unloaded from two of the three LSTs when they moved off the beach at 09.30 and headed off escorted by 10 destroyers and the US fleet tug Sonoma. The 2/3^rd Field Company, 2/1^st Mechanical Equipment Company, 2/3^rd Pioneer Battalion and the Shore Battalion of the US 532^nd Engineer Boat and Shore Regiment prepared four beach exits, through which stores were quickly moved to inland dumps. Some 5,300 men, 180 vehicles, 32 25-pdr and Bofors 40-mm guns, and 850 tons of bulk stores had been unloaded.

Fighters of Lieutenant General George C. Kenney’s US 5^th Army Air Force provided air cover from 06.45. A Japanese reconnaissance aeroplane overflew the beach-head at 09.10, and was shot down. A single bomber arrived 10 minutes later and attacked the LSTs on the beach, but missed. Two dive-bombers attacked at 09.30 but were driven off, though not before inflicting casualties. The Bofors guns of the 10^th Light Anti-Aircraft Battery were attacked, and five men were wounded, one fatally. Over the next two weeks there was at least one air raid on the beach-head every day and were of some benefit to the Australians as they proved an effective way of demanding the rapid clearance of the beach. A large attack by 39 aircraft of Lieutenant General Kumaichi Teramoto’s 4^th Air Army ran into bad weather and had to return to Wewak, but a naval air arm attack by 38 Mitsubishi A6M Reisen 'Zero' single-engined fighters and eight Mitsubishi G4M 'Betty' twin-engined medium bombers found the LSTs and destroyers near the Tami islands group on their way back to Buna at 12.40. The Allied fighter cover was being changed at this time, so the 5^th Army Air Force fighter controller on board the US destroyer Reid could deploy five rather than just three squadrons. The US fighters claimed to have shot down 29 fighters and 10 bombers. Anti-aircraft gunners on the destroyers, LSTs and Sonoma also engaged the bombers, and while torpedo wakes were seen no hits were suffered. Three Lockheed P-38 Lightning twin-engined fighters were shot down, but at least one of their pilots was rescued. The Japanese pilots claimed to have sunk two cruisers, two destroyers and two transport vessels.

A shortage of 9-mm ammunition for the Australians force’s sub-machine guns was discovered, apparently because the ammunition was in the LST that had not been completely unloaded before departure. An emergency air drop was requested at 10.30. In Port Moresby, the 1^st Air Maintenance Company prepared 30 parachutes, each attached to two boxes containing 2,560 rounds of 9-mm ammunition, a total of 153,600 rounds. These were loaded into three US Consolidated B-24 Liberator four-engined heavy bombers at Wards Airfield, and the aircraft took off at 16.55 to arrive over the Finschhafen area after dark at 19.15. Here a drop zone in a kunai patch was marked by men holding hand torches: 115,000 rounds of ammunition were dropped, about 112,000 of which were recovered.

At about the break of day, Pike’s A Company of the 2/17^th Battalion reached the village of Katika, which was a clearing with some dilapidated huts. The company came under fire from Katika Spur, the high ground to the west, which was strongly held by the 9^th Company of the 80^th Regiment and one company of the 238^th Regiment. The Japanese attempted to outflank A Company on its left, but ran into Capitan L. Snell’s D Company of the 2/15^th Battalion. The Japanese positions were well-sited on the spur for an attack from the east along the track linking Katika and Sattelberg, but at this point Captain B. G. Cribb, commander of D Company of the 2/13^th Battalion, reported by radio that he was in contact with the Japanese to the west, and was preparing to attack from that direction. A furious fight ensured. The Japanese held their fire until the Australians were almost on top of them. Realising that the position was stronger than he had thought, Cribb withdrew after suffering eight men killed and 20 wounded. Windeyer ordered the 2/17^th Battalion to bypass the position and proceed to its objective, the high ground to the south of the Song river. The 2/15^th Battalion was ordered to attack Katika Spur. The attack was delivered at 15.15 after a preliminary bombardment by 3-in (76.2-mm) mortars, but the Japanese defenders had withdrawn, leaving behind eight dead. By the fall of night, therefore, most of the 20^th Brigade’s units had reached their objectives.

The seventh wave, comprising the US LST-67, LST-452 and LST-454, reached Scarlet beach at 00.00. As with the previous wave, each of the ships carried an Australian labour force which unloaded the LSTs under the direction of the Shore Battalion. The LSTs fell back from the beach at 03.00 in order to be well clear before dawn. During the first day of 'Diminish', the Australian casualties had been 20 men killed, 65 wounded and nine missing, all of whom were eventually found to be either dead or wounded. The 7^th Amphibious Force reported that three of its men had been wounded.

Blamey relinquished command of the New Guinea Force on 22 September, handing over to Lieutenant General Sir Iven Mackay, and as one of his final actions, instructed Herring to arrange for the reinforcement of Finschhafen with an extra brigade and the headquarters of the 9^th Division. On the same day, however, MacArthur, who also returned to Brisbane on 24 September, had issued an instruction that operations at Finschhafen were 'to be so conducted as to avoid commitment of amphibious means beyond those allotted'. Therefore Barbey declined to arrange for the reinforcement of Finschhafen, so Mackay took up the matter with Carpender, who also demurred. MacArthur feared that committing additional resources would tie them down, and perhaps result in losses, that would delay forthcoming operations and thereby relinquish the initiative to the Japanese. Ironically, the delay in reinforcing Finschhafen would cause just that.

On 27 September Windeyer requested another infantry battalion and one squadron of tanks, and Carpender agreed to ship the additional battalion and, on the following day, Herring flew to Milne Bay to confer with Barbey about this. On take-off from Dobodura, the North American B-25 Mitchell twin-engined medium in which Herring was a passenger, crashed. A flying fragment killed Herring’s chief-of-staff, but although everyone else escaped unscathed the meeting was cancelled. Willoughby still clung to his original estimate of 350 Japanese in the Finschhafen area, but MacArthur authorised the extra battalion. It was arranged that the first LST departing Lae on the night of 28/29 September would pause at G beach and collect the 2/43^rd Battalion and one platoon of the 2/13^th Field Company, a total of 838 men. These were delivered to Buna, where they transferred to the US destroyer transport Brooks, Gilmer and Humphreys. On the following night the three ships made the run to Scarlet beach, where the troops were landed and 134 wounded were taken back, although surf conditions prevented the evacuation of the most seriously wounded men.

While the 20^th Brigade was engaged at Finschhafen, the militiamen of the 22^nd Battalion advanced along the coast from the Hopoi Mission Station toward Finschhafen. This advance had to be made in increasing difficult terrain. Supply using vehicles was impossible, so the 22^nd Battalion was supplied by boats of the US 532^nd Engineer Boat and Shore Regiment. Stores were deposited at advanced beaches and then carried from there by native porters. The 22^nd Battalion fought a number of skirmishes against the 2/80^th Regiment, which had been ordered to withdraw, so the Australian battalion thus discovered a series of well-prepared and strong positions which were either unmanned or soon abandoned. The battalion reached Dreger Harbour on 1 October, and here made contact with the 20^th Brigade.

On 23 September, Windeyer ordered the start of the advance on Finschhafen. At 12.40, Lieutenant Colonel Colin Grace’s 2/15^th Battalion reached the Bumi river, which was 15 to 20 yards (14 to 18 m) wide and appeared fordable, but whose banks contained barbed wire entanglements and strongly fortified Japanese positions. While Yamada was withdrawing toward Sattelberg, as ordered, the marines of the 85^th Garrison Unit remained in place. Yamada had no authority over the marines, and their commander, Captain Tsuzuki, saw no reason to conform to Yamada’s actions and instead planned to hold Finschhafen for as long as possible. Grace ordered Major Ron Suthers to outflank the Japanese position by moving through the foothills of the Kreutberg mountain range, as previously instructed by Windeyer. While not high, these foothills were very steep and covered in thick vegetation.

Suthers halted on the ridge for the night but resumed his advance in the morning, reaching the Bumi at 10.00. The Australians again found the northern bank defended, and therefore tried to find a crossing 150 yards (140 m) upstream. A Japanese sniper with a light machine gun killed B Company’s commander, Captain E. Christie, and Lieutenant N. Harphain. Suthers then ordered Snell to make an assault crossing with D Company. This was done at 13.30, the company crossing in waist-deep water and losing only one man killed in the crossing. During the afternoon, the 2/13^th Battalion crossed the river to the bridgehead secured by B and D Companies.

At 12.30, a large Japanese air raid developed as 20 fighters and 12 bombers struck the Australian positions around Launch Jetty and the Finschhafen airstrip, dropping some 60 bombs. There were heavy casualties: the 2/3^rd Field Company lost 14 men killed and 19 wounded, the 2/12^th Field Regiment lost two men killed and 16 wounded, and the air liaison party’s headquarters was hit, knocking out its radio set and killing Captain Ferrel, its commander. Another eight men were killed and 40 wounded in air raids on 25 September. During the night of 25/26 September, Japanese barges and one submarine were spotted offshore, and Windeyer brought one company of the 2/17^th Battalion back to protect the brigade area.

Meanwhile, D Company of the 2/17^th Battalion had moved along the track to Sattelberg with the intent of capturing that position. The company reported that Sattelberg was unoccupied, but in fact it had captured Jivevenang not Sattelberg. When the mistake was realised and it attempted to take Sattelberg, it discovered that the position was strongly defended. D Company therefore withdrew to Jivevenang.

The advance on Finschhafen continued on 26 September. Since the Salankaua Plantation was reported still to be heavily defended, Windeyer attempted to force the defenders to withdraw. He started with attacks on two hills to the south-west of the plantation. B and D Companies of the 2/15^th Battalion attacked what came to be called 'Snell’s Hill', which was taken in hand-to-hand combat using bayonets. The Australians captured three 13-mm heavy machine guns and seven light machine guns, and buried the bodies of 52 Japanese defenders. The other feature, which came to be called 'Starvation Hill', was taken by C Company. However, the capture of these two features did not prompt the Japanese to abandon the Salankaua Plantation.

Windeyer realised that he needed to capture Kakakog Ridge, but torrential rain was falling, making it difficult to resupply his forward positions, particularly that on 'Starvation Hill'. On 1 October eight Douglas A-20 Havoc twin-engined attack bombers of the US 89^th Bombardment Squadron attacked the Japanese positions in the Salankaua Plantation and Kakakog Ridge area at 10.35, followed by 10 Vultee Vengeance single-engined dive-bombers of the RAAF’s No. 24 Squadron. This was followed by a bombardment by 20 25-pdr gun/howitzers of the 2/12^th Field Regiment each firing 30 rounds. The attack was then delivered, but the assault companies were soon pinned down. Sergeant G. R. Crawford led Nos 11 and 12 Platoons of the 2/13^th Battalion in a bayonet charge on the Japanese positions covering Ilebbe Creek. Private A. J. Rofle, firing a Bren light machine gun from the hip, silenced one of the Japanese posts causing the most trouble, continued to silence another, but was wounded trying to destroy a third. Crawford’s furious assault swept all before it. One post remained on Crawford’s left, which was attacked with 2-in (51-mm) mortars and attacked by No. 8 Platoon. The Japanese abandoned the post and withdrew into the Salankaua Plantation. The 2/13^th Battalion had lost 10 men killed and 70 wounded; between 80 and 100 Japanese marines died.

The arrival of the 2/43^rd Battalion meant that the 2/17^th Battalion could be reassembled for the advance on Finschhafen, thus enabling the entire 20^th Brigade to concentrate on that objective. On 2 October the 2/17^th Battalion crossed the Bumi river without opposition, and found the Salankaua Plantation unoccupied. In mopping up the area, the battalion captured two Japanese stragglers and killed three, and by the evening Finschhafen was in Australian hands. Between 22 September and 2 October, the 20^th Brigade had taken its objectives at the cost of 73 men killed, 276 wounded and nine missing, all of whom were later accounted for as dead or wounded. The 532^nd Engineer Boat and Shore Regiment had eight dead and 42 wounded, and two Americans of the air liaison party were also killed.

MacArthur’s decision to move swiftly against Finschhafen, coupled with Blamey’s decision to envelop the Japanese defences by landing at Scarlet beach, and Yamada’s decision to avoid a decisive engagement that might result in the loss of all or part of his force, had provided Windeyer with the time and space he needed to take Finschhafen. Blamey’s objective was therefore in Allied hands, but it was of limited use without Sattelberg. The Allied intelligence failure and subsequent dithering meant that the Japanese reinforced their position faster, and were thus in the position to seize the initiative. The Japanese launched a counterattack on the Allied lodgement around Scarlet beach. A three-pronged action, the counterattack incorporated a diversionary attack to the north while the Sugino Craft Raiding Unit attacked from the sea and two infantry regiments assaulted the centre aiming toward the beach and the Heldsbach plantation. It had been intended that once the beach-head had been overwhelmed, the 79^th Regiment and 80^th Regiment would link and then clear the area of Finschhafen and Langemark Bay. The Japanese attack was poorly co-ordinated, however, and failed to achieve sufficient weight to overcome the Australians, while also suffering from a lack of artillery. The seaborne assault was interdicted by US PT-boats, which inflicted heavy casualties, and was destroyed by Allied machine gunners on the beach. In the centre, though, the Japanese were able to break through to Siki Cove, and in the process isolated several Australian units, including those fighting on the western flank around Jivevenang, forcing the Australians to resort to air drops to keep their forces supplied.

While the Japanese briefly managed to force the Australians to contract their forces around the beach-head, and Japanese aircraft were able to attack the Allied ground forces around the area over three successive nights between 19 and 21 October, the attack eventually ran out of momentum on 24 October, at which point the Japanese commander, Yamada, ordered his forces to concentrate around the high ground at Sattelberg, where they planned to make further attacks. Meanwhile, the Australians prepared for an assault against the Japanese stronghold that had been established around the abandoned Lutheran mission atop the Sattelberg heights before advancing toward the Wareo plateau to cut the key Japanese lines of communication.