The Battle of Rabaul, also known by the Japanese as Operation R, an instigating action of the New Guinea campaign, was fought on the island of New Britain in the Australian Territory of New Guinea, from 23 January into February 1942. It was a strategically significant defeat of Allied forces by Japan in the Pacific campaign of World War II, with the Japanese invasion force quickly overwhelming the small Australian garrison, the majority of which was either killed or captured. Hostilities on the neighbouring island of New Ireland are usually considered to be part of the same battle. Rabaul was significant because of its proximity to the Japanese territory of the Caroline Islands, site of a major Imperial Japanese Navy base on Truk.
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. Heavy fighting followed along the Kokoda Track, and around Milne Bay, before the Japanese were eventually pushed back towards Buna–Gona by early 1943. As part of Operation Cartwheel, throughout 1943–1945, Allied forces later sought to isolate the Japanese garrison on Rabaul, rather than capturing it, largely using air power to do so, with US and Australian ground forces pursuing a limited campaign in western New Britain during this time.
By the end of the war, there was still a sizeable garrison at Rabaul, with large quantities of equipment that were subsequently abandoned. In the aftermath, it took the Allies over two years to repatriate the captured Japanese soldiers, while clean up efforts continued past the late 1950s. Many relics including ships, aircraft and weapons, as well as abandoned positions and tunnels, remain in the area.
Prelude
Rabaul lies on the eastern end of the island of New Britain. At the time of the battle, the town was the capital of the Australian-administered Territory of New Guinea, having been captured from the Germans in 1914. In March 1941, the Australians dispatched a small garrison to the region, as tensions with Japan heightened. The small Australian Army garrison in New Britain was built around Lieutenant Colonel Howard Carr's 700-strong 2/22nd Battalion, an Australian Imperial Force (AIF) infantry battalion. This battalion formed part of Lark Force, which eventually numbered 1,400 men and was commanded by Lieutenant Colonel John Scanlan. 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. 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.
Throughout 1941, the Allies had planned to build Rabaul up as a "secure fleet anchorage" with plans to establish a radar station and a strong defensive minefield; however, these plans were ultimately shelved. Allied planners later determined that they did not have the capacity to expand the garrison around Rabaul, nor was the naval situation conducive to reinforcing it should the garrison come under attack. Nevertheless, the decision was made that the garrison would remain in place to hold Rabaul as a forward observation post. 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 only 10 lightly armed CAC Wirraway training aircraft and four Lockheed Hudson light bombers 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. The capture of New Britain offered them a deep water harbour and airfields to provide protection to Truk and also to interdict Allied lines of communication between the United States and Australia. Following the capture of Guam, the South Seas Detachment, under Major General Tomitaro Horii, was tasked with capturing Kavieng and Rabaul as part of "Operation R".
Japanese planning began with aerial reconnaissance of the town, which sought to identify the dispositions of the defending troops. Planners, who had been flown from Guam to Truk, determined three possible schemes of manoeuvre based on these dispositions: a landing near Kokop, aimed at establishing a beachhead; a landing on the north coast of Rabaul, followed by a drive on Rabaul from behind the main defences; or a multi-pronged landing focused on capturing the airfields and centre of the town. They settled upon the third option. The Japanese established 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 battalions, an artillery company, signals unit, and a munitions squad, as well as a few platoons from the 55th Cavalry Regiment, a battalion from the 55th Mountain Artillery Regiment and a company from the 55th Engineer Regiment. These forces would be supported by a large naval task force, and landing operations would be preceded by a heavy aerial campaign aimed at destroying Allied air assets in region so they could not interfere with the landing operations.
Battle In December 1941, shortly before Japanese air raids began, most civilian men were forced to stay in Rabaul, but women who were not necessary to the defence of the base were evacuated. 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 headquarters in Melbourne with the Latin phrase "Nos Morituri Te Salutamus" ("we who are about to die salute you"), supposedly uttered by gladiators in ancient Rome before entering combat.
On 14 January, the Japanese force embarked at Truk and began steaming towards Rabaul as part of a naval task force, which consisted of four aircraft carriers— , , Shokaku and Zuikaku — seven cruisers, 14 destroyers, and numerous smaller vessels and submarines under the command of Vice Admiral Shigeyoshi Inoue. On 20 January, over 100 Japanese aircraft attacked Rabaul 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 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 withdrew from Rabaul. 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. RAAF Townsville command ordered 24 Squadron repeatedly to bomb Japanese ships with whatever aircraft available, though this order had come after the squadron was reduced to two Wirraways, one too damaged and one lacking bomb pylons, and one Hudson. The Hudson was wrought out of its camouflaged position and launched with a light payload near the dusk of January 21st bound to bomb the concentrated enemy fleet near Kavieng, but returned as darkness settled too soon. At this turn, the remaining Hudson, with a somewhat malfunctioning engine, was used to evacuate severely wounded RAAF personnel to Australia, and it departed at 0300 January 22 for Port Moresby, where it refuel before heading to Australia, in violation of Townsville's orders. Once this aircraft departed, the RAAF personnel set to demolishing Vunakanau's base infrastructure, including the runways and ammunition. At 1600 hours on the same day, Lark force engineers conducted what was described as a 'botched demolition' of nearly two thousand aerial bombs, all at once, that had been unloaded from the transport Herstein earlier, the explosion was massive and leveled buildings at a radius of a quarter mile, and caused extensive damage as far as half a mile, the hurried demolition also killed numerous natives who were caught in the open. The bombing continued around Rabaul on 22 January, with a targeted carrier strike destroying most of the coastal batteries and killing or wounding twenty Australian artillerists as well as destroying more infrastructure, though accurate dive bombing attempts failed to destroy the two anti-aircraft guns that were lodged on a slope overlooking Vunakanau, one of Kaga's Type 0 fighters piloted by FPO 2nd Class Isao Hiraishi was fatally damaged by a bullet to the fuel tank and crashed near the sea due to fuel starvation, making the only combat loss of that day's raid, though two of the attacking Type 99 carrier dive bombers become operation losses as they later made a crash landing near their carriers. At 230 hours that morning a Japanese force of between 3,000 and 4,000 troops landed at 3 locations just off New Ireland and waded ashore in deep water filled with dangerous mud pools. 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, under the command of Lieutenant Colonel Kuwada Ishiro, 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, Lakunai airfield had been captured by the Japanese force. Assessing the situation as hopeless, 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.