Borneo campaign
The Borneo campaign or Second Battle of Borneo 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 1945 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, localised fighting 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.
This article is about the 1945 Allied campaign in Borneo. For the 1941-42 Japanese conquest of the island, see Battle of Borneo (1941–1942), Battle of Tarakan (1942), and Battle of Balikpapan (1942).Background[edit]
Prior to World War II, Borneo was divided between British Borneo, in the north of the island and Dutch Borneo in the south; the latter formed part of the Netherlands East Indies (NEI). As of 1941, the island's population was estimated to be 3 million. The great majority lived in small villages, with Borneo having less than a dozen towns. Borneo has a tropical climate and was mainly covered by dense jungle at the time of World War II. Most of the coastline was lined with mangroves or swamps.[5]
Borneo was strategically important during World War II. The European colonisers had developed oil fields and their holdings exported other raw materials. The island's location was also significant, as it sat across the main sea routes between north Asia, Malaya and the NEI. Despite this, Borneo was under-developed, and had few roads and only a single railroad. Most travel was by watercraft or narrow paths. The British and Dutch also stationed only small military forces in Borneo to protect their holdings.[5]
Borneo was rapidly conquered by the Japanese in the opening weeks of the Pacific War. The purpose of this operation was to capture the oilfields and guard the flanks of advances into Malaya and the NEI.[5][6] Japanese troops landed at Sarawak on 16 December 1941, where a single battalion of British Indian troops fought a delaying action over several weeks, damaging vital oil installations. Meanwhile, on 11 January 1942, Japanese troops landed on the island of Tarakan, while parachute troops carried out a drop on the Celebes the following day; the small Dutch garrison managed to destroy some of the infrastructure before eventually being overwhelmed.[7] The destruction of these facilities led to harsh reprisals against civilians, particularly at Balikpapan where between 80 and 100 Europeans were executed.[8][9]
In the aftermath, the Imperial Japanese Army (IJA) administered the occupied British North Borneo and the Imperial Japanese Navy (IJN) was responsible for Dutch Borneo. The garrison forces on the island were very small until mid-1944.[10] During the occupation, the local population was subjected to harsh treatment. For example, on Tarakan large numbers of people were conscripted as labourers, the economy was disrupted, and food became increasingly scarce. In October 1943, an open revolt by local Dayak tribesmen and ethnic Chinese initiated the Jesselton revolt which was violently suppressed with hundreds being executed. In the aftermath, many more died from diseases and starvation as Japanese policies became even more restrictive on the local population.[11] Japanese forces conducted a number of other massacres during their occupation of Borneo.[12]