The Battle of Finschhafen was part of the Huon Peninsula campaign in New Guinea during World War II and was fought between Australian and Japanese forces. The fighting took place between 22 September and 24 October 1943 following the landing at Scarlet Beach, which was followed by a two-pronged advance on Finschhafen as the Australian 20th Infantry Brigade advanced on the town from the north, while the 22nd Infantry Battalion drove from the south, having advanced from the landing beaches east of Lae. After the capture of Finschhafen, the Japanese forces in the area withdrew towards Sattelberg where they sought to hold the Australians before launching a counteroffensive, which subsequently threatened the landing beach. This attack was repelled by Australian and American forces, with heavy casualties being inflicted on the Japanese. In the aftermath, the Australians went on the offensive, capturing Sattelberg, and then advancing towards the Wareo plateau.
Background Finschhafen had been occupied by the Imperial Japanese Army on 10 March 1942 as part of strategic moves to provide protection to Lae, which they had established as an important air base. Throughout early 1943, the Allies had begun offensive operations in the Salamaua area of New Guinea and following the landing at Nadzab and capture of Lae in early September 1943, the Allies attempted to exploit their success with an advance to Finschhafen to begin the Huon Peninsula campaign.
The operation to capture Finschhafen was important to capture the western cape of the Vitiaz Strait for the construction of airfields and naval facilities for the upcoming New Britain campaign as part of Operation Cartwheel. The responsibility for securing the Huon Peninsula was assigned to Major General George Wootten's Australian 9th Division. On 22 September, the Australian 20th Infantry Brigade, under the command of Brigadier Victor Windeyer, supported by artillery from the 2/12th Field Regiment, as well as a field company of engineers and a field ambulance, had landed at Scarlet Beach – about north of Finschhafen – and proceeded to establish a beachhead there. At the same time, the 22nd Infantry Battalion, an Australian Militia unit that had landed east of Lae in early September to relieve the troops holding the beachhead, began pursuing the Japanese that were withdrawing to the east, marching from Hopoi Mission Station towards Finschhafen, with a view to placing pressure on the Japanese southern flank.
The Japanese had expected an Allied assault on the Finschhafen region from around late July 1943, having appreciated its significance in relation to the Vitiaz and Dampier Straits. The Japanese Eighteenth Army commander, Lieutenant General Hatazo Adachi, had begun moving forces into the region. The majority of these were drawn from the 20th Division, which dispatched a force of about 2,800 men from Madang in August. These forces consisted of the 80th Infantry Regiment, one battalion of the 26th Field Artillery Regiment, and the 7th Naval Base Force. In addition, following the fall of Lae, elements of the 41st Division – primarily the 238th Infantry Regiment – and the 51st Division's 102nd Infantry Regiment, were also moved to the area, and were placed under the command of Major General Eizo Yamada, commander of the 1st Shipping Group. The total number of Japanese in the area was around 4,000 to 5,000, although Allied intelligence estimated a strength of between 350 and 2,100.
Yamada's forces were spread out in a series of outposts that were orientated around a main defensive position established at Sattelberg, an abandoned Lutheran mission situated atop a mountain that dominated the terrain about north-west of Finschhafen. The Japanese forces lacked transportation and the road network had not been fully developed. They were low on ammunition for all calibres of weapons, especially artillery, and the majority of stores had to be carried by combat troops, as local carriers had ceased working for the Japanese in response to Allied propaganda. Following the landing at Scarlet Beach, Yamada was ordered to launch an attack on the Australian forces in order to delay them so that further reinforcements could arrive from the 20th Division.
Battle Australian drive on Finschhafen
After the landing, the Australians began establishing a beachhead several kilometres deep, during which significant actions were fought around Siki Cove and Katika. Late in the day, a large Japanese air raid struck the Allied fleet off shore, but this was eventually defeated by a strong US fighter umbrella that was forewarned by Allied picket ships. The following day, 23 September, the 20th Brigade's drive on Finschhafen began, with two battalions commencing the advance south – the 2/13th and 2/15th supported by the 2/12th Field Regiment as well as engineers from the 2/3rd Field Company – while the 2/17th was split up, with two companies advancing as part of the brigade's reserve, while another remained to secure the beachhead from a Japanese attack and push it further to the north, and the fourth pushed towards Sattelberg. The 2/3rd Pioneer Battalion remained in the beachhead, working to improve roads, while the 2/8th Field Ambulance set up a main dressing station, which would receive casualties as they were evacuated rearwards from the advanced dressing station that was following the battalions advancing south.
In addition to having to split their forces, the Australians also suffered from supply difficulties during the advance. The terrain over the southerly approaches was quite difficult being primarily dense jungle with numerous water crossings and rugged features. To traverse the ground, the Australians had only limited vehicles, with each infantry battalion possessing four jeeps with trailers for resupply, while the engineers and artillery had several trucks and tractors. The local population, which might have been employed to carry stores, had abandoned the Japanese due to Allied propaganda and their services were also unavailable to the Allies at the initial stages of the campaign. As a result, a large amount of stores had to be carried by combat soldiers, who were diverted to the task. Nevertheless, the Australian advance succeeded in capturing the Heldsbach plantation and the nearby airfield. It continued until the Australians came up against strong resistance around the Bumi River. There a force of around 300 Japanese sailors and marines from the 85th Naval Garrison, reinforced by elements of the 238th Infantry Regiment, established themselves in a blocking position. Although they were under orders to conform to the overall Japanese plan of delaying the Australians and then withdrawing towards Sattelberg to carry out a containment operation, the commander of the naval troops resolved to hold the position, and they subsequently held up the Australian advance on 26 September, until they were overcome through an attack on their flanks by the 2/15th Infantry Battalion.
In response to concerns about the large number of Japanese forces in the area, which had proven to be in larger numbers than Allied intelligence had estimated, Windeyer requested reinforcements. These were initially refused as US naval commanders baulked at the idea of transporting another brigade to Finschhafen due to the risks involved and potential naval losses that might be incurred. In addition, the Allied higher headquarters under General Douglas MacArthur was operating under the mistaken belief that the Japanese defending the area were only very small in number, when in actuality the two forces were roughly equal in size, with the Allied strength after the landing being around 5,300. After much discussion amongst Australian and US commands on 29/30 September the 2/43rd Infantry Battalion arrived to relieve the 2/17th. The South Australians from the 2/43rd were subsequently tasked with defending the beachhead and the surrounding areas including the Heldsbach area, and were ordered to prepare for further actions around Sisi and Sattelberg. Heavy rain fell around this time, and the Australian brigade commander was compelled to use combat troops to carry stores forward from the landing zone to the forward areas as motor transport was unable to transit the primitive track system. Due to concerns about their western flank, the 2/17th extended the Australian perimeter towards Jivevaneng, establishing a company there, but it subsequently came under attack on the Sattelberg Road and west of Katika on 25 and 26 September from the Japanese 80th Infantry Regiment, which was trying to break through to the Heldsbach Plantation on the coast. Over the course of several days, the company from the 2/17th around Jivevaneng held off six Japanese attacks until relieved by the 2/43rd Infantry Battalion on 30 September.
Meanwhile, concerned about their rear, due to the presence of a large number of Japanese troops around Sattelberg, the Australians pushed cautiously to Kakakog, which saw heavy fighting at the end of the month, resulting in around 100 Japanese casualties as the Australians called in artillery fire and air attacks to soften up the Japanese defences prior to an attack by the 2/13th Infantry Battalion, supported by Vickers machine guns from the 2/15th. From the south, the 22nd Infantry Battalion advanced north against limited opposition. On 1 October, they crossed the Mape River adjacent to Langemak Bay, while the forward troops from the 20th Infantry Brigade, overwhelmed a Japanese force around Kakakog, supported by artillery and air power, killing between 80 and 100 defenders. Following this, the Japanese began withdrawing from Finschhafen and the next day, the 20th Infantry Brigade reached their objective, entering Finschhafen in the afternoon after overcoming limited resistance. The two forces married up the following day as troops from the 2/17th contacted the 22nd.
This ended the first phase of the battle. During operations to capture Finschhafen, the Australians lost 73 killed, 285 wounded. Sickness also resulted in a further 391 evacuations. Japanese casualties were reported as "heavy", but Allied intelligence assessed that a large number of Japanese forces remained at large and had withdrawn west away from the coast in preparation for further fighting. In the same time, US forces from the 532nd Engineer Boat and Shore Regiment lost eight killed and about 42 wounded, mainly during the landing operations around Scarlet Beach.
Japanese counterattack Following the capture of Finschhafen, the main part of the Australian 20th Infantry Brigade returned to Scarlet Beach, due to intelligence that the Japanese were about to attack. The 2/13th and 22nd Infantry Battalions were left around Finschhafen, while the 2/15th and 2/17th Infantry Battalions were re-orientated to defend the approaches to Scarlet Beach. Around Jivevaneng, east of Sattelberg, the 2/43rd had taken up a blocking position and in the early days of October fought a Japanese attack by a battalion from the 80th Infantry Regiment along the coast road to a halt. In an effort to shore up their western flank, the Australian 2/17th Infantry Battalion pressed towards Kumawa, which was met with a fierce response from the Japanese on 5 October when their line of communication from the west was threatened. The battalion continued to fight around Jivevaneng, and on 10 October they secured a piece of high ground called the "Knoll" by the Australians, who subsequently defeated 12 attacks to take it back.