When a veteran of the Bougainville campaign, Peter Medcalf, sat down in the early 1980s to write his memoir of the campaign, he came up with the title War in the Shadows. It was a statement both on the type of fighting experienced on the island – jungle warfare in the shadowy half-light under dense jungle canopies – and the sense those taking part had of being 'forgotten'.
Bougainville Island and the adjacent, smaller Buka Island form part of the Solomon Islands chain. They were the outermost islands of the Australian administered League of Nations' mandated territory of New Guinea. The Japanese invaded the two islands in early 1942 when fewer than 20 Australian troops and a couple of naval coastwatchers were stationed there. The soldiers withdrew inland to observe the enemy and later were evacuated, leaving the coastwatchers to continue reporting Japanese air and sea movements. Their radio messages warning of convoys and air raids helped the Americans achieve victory to the south-east at Guadalcanal. This battle was the start of the American 'island hopping' campaign recapturing a string of islands from the Japanese.
In November 1943, American forces landed at Torokina on the western side of Bougainville Island. Along with some New Zealand and Fijian troops, they established and defended a base there. The Americans intended only to secure this base, building airfields and supply depots, to support subsequent operations beyond the island. They were content to leave most of Bougainville and all of Buka Island in Japanese hands.
Allied air and sea superiority meant that the Japanese garrison, the 17th Army, effectively was cut off from the main Japanese forces. The Japanese could not get supplies in and had no air cover. Without resupply, they could not mount an effective attack on the American base at Torokina. Only once, in early 1944, was a major attack on the base launched. It failed. After that, Bougainville became a backwater of the war.
In the middle of 1944, there began a handover of responsibility for the base at Torokina to Australian forces. Rather than merely hold the enemy at bay, as the Americans had done, Australia's political leaders and senior officers decided the Australian force would go on the offensive.
The Japanese were concentrated in three main areas. One force was positioned at Numa Numa on the north-east coast and had sent troops over the Numa Numa Trail across the island towards Torokina. To the south, a major garrison force was located at Buin, on the southern tip of the island, while in the north another large force occupied the Bonis Peninsula on the northern tip of Bougainville Island and also Buka Island. The Australians were to advance on all three locations. The Japanese commander ordered his forces to step up patrols and prepare to fight, but believed the Australians would not launch their attacks before January 1945.
In fact, the Australians were ready shortly after arriving. The commander of II Australian Corps, Lieutenant-General Stanley Savige, realised speed offered his force an element of surprise. He had under his command the 3rd Australian Division along with two independent infantry brigades, the 11th and 23rd Brigades, along with supporting troops. Air support was provided mostly by the Royal New Zealand Air Force, with Australian aircraft limited to some tactical reconnaissance, artillery spotter and transport aircraft.
General Savige launched a three-pronged attack against the Japanese in November 1944. He ordered the 7th Infantry Brigade to begin the advance over the mountains towards Numa Numa. The brigade met stiff resistance from the Japanese, with heavy fighting in the mountains around Pearl Ridge. The Japanese had a freshly reinforced infantry battalion with light artillery and mortar support – a formidable force for the Australians to overcome. It took some hard fighting around Pearl Ridge and Artillery Hill for the Australians to secure the heights in the centre of the mountainous range. From the highest peaks, they were able to look out at the sea on both sides of the island.
Meanwhile the 11th Infantry Brigade was sent north from Torokina. Its orders were to push back the Japanese and, if possible, force them into the interior of the island where they might be starved out. The advance went well until the end of January when the Japanese launched a heavy counter-attack near the Genga River. It took further hard fighting, with artillery support, to break the Japanese. The Australians then pushed on and by the end of April had secured the Soraken Peninsula, hemming the Japanese into a small area on the northern tip of the island. However, an attempt to insert a company of the 31st/51st Battalion behind the Japanese lines was disastrous. The men went ashore in landing craft but had be evacuated after 48 hours, rescued by landing craft crews under heavy fire, having lost 23 men killed and more than 100 wounded.
To the south, the Australian advance also went well. One battalion at a time attacked the Japanese and they made steady ground. In March and April 1945, however, the Japanese counter-attacked with a series of human wave attacks at Slater's Knoll, about half-way towards Buin. In heavy fighting, and with the assistance of tanks and also air support, the Australians held their ground. On 22 March, Corporal Reg Rattey, 25th Battalion, became the first soldier from a militia battalion to be awarded the Victoria Cross – the highest decoration for valour – in action at Slater's Knoll.
Nearly 300 dead Japanese were found around Slater's Knoll after the battle. Over the following weeks, the Australians pressed on towards Buin but were now under pressure to take the advance easy to reduce casualties to a bare minimum.
For the rest of the war, the war on Bougainville was one of containment of the Japanese. However, there was still some hard fighting, particularly in the north, where the 23rd Infantry Brigade took over the Australian operations. In fact, on 24 July 1945, the last Army Victoria Cross of the war was won by 20-year-old Private Frank Partridge, 8th Battalion, when he dashed forward during a battle to knock out a Japanese bunker and then lead an attack against a second.
The campaign on Bougainville Island was one of the most costly land campaigns in the Pacific for Australia. It cost more than 500 lives and more than 1500 wounded. Many felt this cost in lives was unnecessary, for the campaign made no difference to the outcome of the war. All it achieved was to push back the Japanese into smaller areas of containment. It has for this reason remained one of the most controversial campaigns of the war.