Battle of Rabaul ( 1942 ) The Battle of Rabaul , also known by the Japanese as Operation R , was fought on the island of New Britain in the Australian Territory of New Guinea , in January and February 1942 . It was a strategically significant defeat of Allied forces by Japan in the Pacific campaign of World War II . Following the capture of the port of Rabaul , Japanese forces turned it into a major base and proceeded to land on mainland New Guinea , advancing toward Port Moresby and Australia . Hostilities on the neighbouring island of New Ireland are also usually considered to be part of the same battle . Rabaul was important because of its proximity to the Japanese territory of the Caroline Islands , site of a major Imperial Japanese Navy base on Truk . Prelude . The 1 , 400 - strong Australian Army garrison in New Britain — known as Lark Force — was commanded by Lieutenant Colonel John Scanlan . It included 716 frontline Australian Imperial Force ( AIF ) soldiers in the shape of the 2 / 22nd Battalion , deployed from March 1941 as fears of war with Japan increased . The force also included personnel from a local Militia unit , the New Guinea Volunteer Rifles ( NGVR ) , a coastal defence battery , an anti - aircraft battery , an anti - tank battery and a detachment of the 2 / 10th Field Ambulance . < ref name = 2 / 22nd > < / ref > The 2 / 22nd Battalion Band — which was also included in Lark Force — is perhaps the only military unit ever to have been entirely recruited from the ranks of the Salvation Army . A commando unit , the 130 - strong 2 / 1st Independent Company , was detached to garrison the nearby island of New Ireland . The main tasks of the garrison were protection of Vunakanau , the main Royal Australian Air Force ( RAAF ) airfield near Rabaul , and the nearby flying boat anchorage in Simpson Harbour , which were important for the surveillance of Japanese movements in the region . However , the RAAF contingent , under Wing Commander John Lerew , had little offensive capability , with 10 lightly armed CAC Wirraway training aircraft and four Lockheed Hudson light bomber s from No . 24 Squadron . For the Japanese , Rabaul was important because of its proximity to the Caroline Islands , which was the site of a major Imperial Japanese Navy base on Truk . Following the capture of Guam , the South Seas Force , under Major General Tomitaro Horii , was tasked with capturing Kavieng and Rabaul , as part of " Operation R " . A brigade group based on the 55th Division , its main combat units were the 144th Infantry Regiment , which consisted of a headquarters unit , three infantry battalion s , an artillery company , signals unit , and a munitions squad , as well as a few platoon s from the 55th Cavalry Regiment , a battalion from the 55th Mountain Artillery Regiment and a company from the 55th Engineer Regiment . On 14 January , the force embarked at Truk as part of a naval task force , which consisted of two aircraft carriers — and — seven cruisers , 14 destroyers , and numerous smaller vessels and submarines under the command of Vice Admiral Shigeyoshi Inoue . Battle . Starting on 4 January 1942 , Rabaul came under attack by large numbers of Japanese carrier - based aircraft . After the odds facing the Australians mounted significantly , Lerew signalled RAAF HQ in Melbourne with the Latin motto " " Nos Morituri Te Salutamus " " ( " we who are about to die salute you " ) , the phrase uttered by gladiator s in ancient Rome before entering combat . On 20 January , over 100 Japanese aircraft attacked in multiple waves . Eight Wirraways attacked and in the ensuing fighting three RAAF planes were shot down , two crash - landed , and another was damaged . Six of Australian aircrew were killed in action and five wounded . One of the attacking Japanese bombers was shot down by anti - aircraft fire . As a result of the intense air attacks , Australian coastal artillery was destroyed and Australian infantry were withdrawn from Rabaul itself . The following day , an RAAF Catalina flying boat crew located the invasion fleet off Kavieng , and its crew managed to send a signal before being shot down . As the Australian ground troops took up positions along the western shore of Blanche Bay where they prepared to meet the landing , the remaining RAAF elements , consisting of two Wirraways and one Hudson , were withdrawn to Lae . Once the aircraft had departed with a number of wounded , the Australians destroyed the airfield . The bombing continued around Rabaul on 22 January and early that morning a Japanese force of between 3 , 000 and 4 , 000 troops landed just off New Ireland and waded ashore in deep water filled with dangerous mudpools . The 2 / 1st Independent Company had been dispersed around the island and the Japanese took the main town of Kavieng without opposition ; after a sharp fight around the airfield the commandos fell back towards the Sook River . That night , the invasion fleet approached Rabaul and before dawn on 23 January , the South Seas Force entered Simpson Harbour and a force of around 5 , 000 troops , mainly from the 144th Infantry Regiment , commanded by Colonel Masao Kusunose , began to land on New Britain . A series of desperate actions followed near the beaches around Simpson Harbour , Keravia Bay and Raluana Point as the Australians attempted to turn back the attack . The 3rd Battalion , 144th Infantry Regiment was held up at Vulcan Beach by a mixed company of Australians from the 2 / 22nd and the NGVR , but elsewhere the other two battalions of the South Seas Force were able to land at unguarded locations and began moving inland . Within hours , Scanlan ordered " every man for himself " , and Australian soldiers and civilians split into small groups , up to company size , and retreated through the jungle , moving along the north and south coasts . During the fighting on 23 January , the Australians lost two officers and 26 other ranks killed in action . Only the RAAF had made evacuation plans . Although , initially ordered to turn his ground staff into infantrymen in a last - ditch effort to defend the island , Larew insisted that they be evacuated and organised for them to be flown out by flying boat and his one remaining Hudson . Australian soldiers remained at large in the interior of New Britain for many weeks , but Lark Force had made no preparations for guerrilla warfare on New Britain . Without supplies , their health and military effectiveness declined . Leaflets posted by Japanese patrols or dropped from planes stated in English , " you can find neither food nor way of escape in this island and you will only die of hunger unless you surrender " . Over 1 , 000 Australian soldiers were captured or surrendered during the following weeks after the Japanese landed a force at Gasmata , on New Britain ' s south coast , on 9 February , severing the Australians ' line of retreat . Aftermath . From mainland New Guinea , some civilians and individual officers from the Australian New Guinea Administrative Unit organised unofficial rescue missions to New Britain , and between March and May about 450 troops and civilians were evacuated by sea . The Japanese quickly repaired the damage to Rabaul ' s airfield and Rabaul became the biggest Japanese base in New Guinea , and the lynchpin to their defences in the region . The Australians tried to restrict its development soon after its capture by a bombing counter - attack in March . A handful of Lark Force members remained at large on New Britain and New Ireland and , in conjunction with the local islanders , conducted guerrilla operations against the Japanese , serving mainly as coast watchers , providing information of Japanese shipping movements . Of the over 1 , 000 Australian soldiers taken prisoner , around 160 were massacred on or about 4 February 1942 in four separate incidents around Tol and Waitavalo . Six men survived these killings and later described what had happened to a Court of Inquiry . The Australian government concluded the prisoners were marched into the jungle near Tol Plantation in small groups and were then bayonet ed by Japanese soldiers . At the nearby Waitavalo Plantation , another group of Australian prisoners were shot . The Allies later placed responsibility for the incident on Masao Kusunose , the commanding officer of the 144th Infantry Regiment , but he committed suicide before he could stand trial in 1947 . At least 800 soldiers and 200 civilian prisoners of war — most of them Australian — lost their lives on 1 July 1942 , when the ship on which they were being transported from Rabaul to Japan , the " Montevideo Maru " , was sunk off the north coast of Luzon by the U . S . submarine . In December 1943 , during the Battle of Cape Gloucester , U . S . Marines landed in western New Britain and subsequent Allied operations on New Britain gradually restricted the Japanese force to Rabaul , as part of Operation Cartwheel . In November 1944 , the Australians returned to the island when advanced elements 5th Division landed at Jacquinot Bay on the south coast , and relieved the US 40th Infantry Division . The Australians then conducted a number of other landings around the island as they conducted a limited advance north , securing a line across the base of the Gazelle Peninsula between Wide Bay and Open Bay . After this , they sought to isolate and contain the main Japanese forces around Rabaul . When Japan surrendered in August 1945 , it was found that there were still around 69 , 000 Japanese troops in Rabaul .