
The Battle of Biak was part of the Western New Guinea campaign of World War II, fought between the United States Army and the Japanese Army from 27 May to 17 August 1944. Taking place on the island of Biak, in Geelvink Bay, in present-day Indonesia, it was part of General Douglas MacArthur's Southwest Pacific Command's offensive drive to clear New Guinea in preparation for an invasion of the Philippines. It was the first major effort by the Japanese to allow uncontested landings for the purpose of creating a kill zone inland. The main Allied objective was to capture the island so that they could construct airfields there. The battle resulted in the capture of the island by Allied forces, which were then used to support operations elsewhere in the Pacific.

The Battle of Borneo was a successful campaign by Japanese Imperial forces for control of Borneo island and concentrated mainly on the subjugation of the Raj of Sarawak, Brunei, North Borneo, and the western part of Kalimantan that was part of the Dutch East Indies. The Japanese main unit for this mission was the 35th Infantry Brigade led by Major-General Kiyotake Kawaguchi.

The Battle of Hollandia was an engagement between Allies of World War II and Japanese forces during World War II. The majority of the Allied force was provided by the United States, with the bulk of two United States Army infantry divisions being committed on the ground. Air and naval support consisted largely of U.S. assets, although Australia also provided air support during preliminary operations and a naval bombardment force.

The Borneo campaign of 1945 was the last major Allied campaign in the South West Pacific Area during World War II to liberate Japanese-held British Borneo and Dutch Borneo. Designated collectively as Operation Oboe, a series of amphibious assaults between 1 May and 21 July were conducted by the Australian I Corps, under Lieutenant-General Leslie Morshead, against Imperial Japanese forces who had been occupying the island since late 1941 – early 1942. The main Japanese formation on the island was the Thirty-Seventh Army under Lieutenant-General Masao Baba, while the naval garrison was commanded by Vice-Admiral Michiaki Kamada. The Australian ground forces were supported by US and other Allied air and naval forces, with the US providing the bulk of the shipping and logistic support necessary to conduct the operation. The campaign was initially planned to involve six stages, but eventually landings were undertaken at four locations: Tarakan, Labuan, North Borneo and Balikpapan. Guerilla operations were also carried out by Dayak tribesmen and small numbers of Allied personnel in the interior of the island. While major combat operations were concluded by mid-July, mopping-up operations continued throughout Borneo until the end of the war in August. Initially intended to secure vital airfields and port facilities to support future operations, preparatory bombardment resulted in heavy damage to the island's infrastructure, including its oil production facilities. As a result, the strategic benefits the Allies gained from the campaign were negligible.

The Free Republic of Nias was a short-lived, unrecognized state proclaimed by German prisoners on the Indonesian island of Nias. It existed for less than a month until the island was fully occupied by Japanese troops on 22 April 1942.

The Great East was a governorate (gouvernement) of the Dutch East Indies between 1938 and 1946. It comprised all the islands to the east of Borneo and of Java. Its capital was Macassar on Celebes.

The Greater East Asia Co-Prosperity Sphere , or the GEACPS, was an imperialist concept which was developed in the Empire of Japan and propagated to Asian populations which were occupied by it from 1931 to 1945. It extended across the Asia-Pacific and promoted the cultural and economic unity of East Asians, Southeast Asians, South Asians and Oceanians. It also declared the intention to create a self-sufficient bloc of Asian nations which would be led by the Japanese and this bloc would also be free from the rule of Western powers. The idea was announced in a radio address which was titled "The International Situation and Japan's Position" and delivered by Foreign Minister Hachirō Arita on 29 June 1940.

The Japanese Empire occupied the Dutch East Indies, during World War II from March 1942 until after the end of the war in September 1945. In Indonesian history, the period was one of the most critical.

The Lost Battalion was the 2nd Battalion, 131st Field Artillery, 36th Infantry Division of the U.S. Army. The men of the battalion, plus the survivors of the sunken Cruiser USS Houston, were captured by the Japanese on the island of Java in the Dutch East Indies in March 1942. It is called the lost battalion because the fate of the men was unknown to the United States until September 1944. They were prisoners of war for 42 months until the end of World War II. 534 soldiers from the battalion and 368 survivors of the Houston were taken prisoner. Most of the men were sent to Thailand to work on the Burma Railway, the building of which is portrayed in the film The Bridge on the River Kwai. Of the 902 soldiers and sailors taken captive, 163 died in captivity. Most of the prisoners of war were from western Texas.

The New Guinea campaign of the Pacific War lasted from January 1942 until the end of the war in August 1945. During the initial phase in early 1942, the Empire of Japan invaded the Australian-administered Mandated Territory of New Guinea and the Australian Territory of Papua and overran western New Guinea, which was a part of the Netherlands East Indies. During the second phase, lasting from late 1942 until the Japanese surrender, the Allies—consisting primarily of Australian forces—cleared the Japanese first from Papua, then the Mandate and finally from the Dutch colony.

The Battle of Hollandia was an engagement between Allies of World War II and Japanese forces during World War II. The majority of the Allied force was provided by the United States, with the bulk of two United States Army infantry divisions being committed on the ground. Air and naval support consisted largely of U.S. assets, although Australia also provided air support during preliminary operations and a naval bombardment force.

The Western New Guinea campaign was a series of actions in the New Guinea campaign of World War II. Dutch East Indies KNIL, United States and Australian forces assaulted Japanese bases and positions in the northwest coastal areas of Netherlands New Guinea and adjoining parts of the Australian Territory of New Guinea. The campaign began with Operations Reckless and Persecution, which were amphibious landings by the U.S. I Corps at Hollandia and Aitape on 22 April 1944. Fighting in western New Guinea continued until the end of the war.