First stage of the Borneo campaign in WWII
The Battle of Tarakan was the first stage in the Borneo campaign of 1945. It began with an amphibious landing by Allied forces on 1 May, code-named Operation Oboe One; the Allied ground forces were drawn mainly from the Australian 26th Brigade, but included a small element of Netherlands East Indies personnel. The main objective of the landing was the capture of the island's airfield. While the battle ended with success for the Allied forces over the Japanese defenders, this victory is generally regarded as having not justified its costs. The airfield was so heavily damaged that it ultimately could not be repaired in time to make it operational for other phases of the Allied campaign in Borneo.
Background.
Geography.
Tarakan is a triangle-shaped island off the coast of Borneo. The island is roughly long from its northernmost point to the southern tip and wide towards the north of the island. The small island of Sadau is located about off Tarakan's west coast. Almost all of Tarakan's coastline is swampy, and in 1945 mangroves on the northern half of the island stretched to inland. The coastal mangroves in the southern portion of the island were narrower. Inland from the swamps, most of central Tarakan comprised a series of steep and densely forested hills just over high. Tarakan is located three degrees north of the equator and has a tropical climate. The maximum temperature for most days is about , and relative humidity is consistently high at about 90 percent.
In 1945, Tarakan Town was the main settlement of the island. This town was located inland, and was separated from the south-west coast by several small hills covered in low vegetation. Four piers used to dock oil tankers were located on this coastline at the settlement of Lingkas, and were connected to Tarakan Town by three surfaced roads. Tarakan airfield was located about north-west of Tarakan Town. Of the island's two oilfields, Sesanip Oilfield was located at the north-east edge of the airfield while the larger Djoeata or Juata Oilfield was to the north. The village of Djoeata was located on Tarakan's north-west coast and linked to Djoeata Oilfield by a track.
Japanese occupation.
Prior to World War II, Tarakan formed part of the Netherlands East Indies (NEI) and was an important oil production centre. The island's two oilfields produced 80,000 barrels of oil per month in 1941. Securing Tarakan's oilfields formed one of Japan's early objectives during the Pacific War. Japanese forces landed on the island's east coast on 11 January 1942. They defeated the small Dutch garrison during two days of fighting in which half the defenders were killed in battle or executed thereafter. While the oilfields were sabotaged by the Dutch before surrendering, Japanese engineers were able to swiftly restore them to production. By early 1944 350,000 barrels of oil were being extracted from the island each month.
Tarakan's 5,000 inhabitants suffered under Japan's occupation policies. The large number of troops stationed on the island caused food shortages and many civilians suffered from malnutrition. The Japanese authorities brought 600 labourers to Tarakan from Java who were treated brutally. Approximately 300 Javanese women also travelled to Tarakan after receiving false offers of clerical and clothes-making jobs from the Japanese and were forced to work as prostitutes.
Tarakan's value to the Japanese evaporated with the rapid advance of Allied forces into the area during 1944. The last Japanese oil tanker left Tarakan in July 1944, and heavy Allied air raids later in the year destroyed the oil production and storage facilities. Hundreds of Indonesian civilians may have also been killed by these raids. The Allies also laid mines near Tarakan, which, combined with patrols by air and naval units, prevented Japanese merchant vessels and transports from docking at the island.
In line with the island's declining importance, the Japanese garrison on Tarakan was reduced in early 1945. One of the two infantry battalions stationed on the island (the 454th Independent Infantry Battalion) was withdrawn to Balikpapan. This battalion was destroyed by the Australian 7th Division in July during the Battle of Balikpapan.
Planning.
Allied plans.
The primary objective for the Allied attack on Tarakan (code-named "Oboe One") was to secure and develop the island's airstrip so that it could be used to provide air cover for subsequent landings in Brunei, Labuan and Balikpapan. The secondary objective for the operation was to secure Tarakan's oilfields and bring them into operation as a source of oil for the Allied forces in the theatre. The 3rd Company, Technical Battalion, KNIL was responsible for this.
The 9th Division and 26th Brigade headquarters were responsible for planning the invasion of Tarakan. This work began in early March when both units had arrived at Morotai, and the final plans were completed on 24 April. The planners' work was hampered by poor working conditions and difficulties in communicating with General MacArthur's General Headquarters at Leyte. As part of the planning process each of Tarakan's hills was assigned a code name (for instance "Margy" and "Sykes"); during the Australian Army's campaigns in New Guinea geographic features had been named on an ad hoc basis, and it was hoped that selecting names prior to the battle would improve the precision of subsequent planning and communications.
The Allied planners possessed detailed intelligence on Tarakan and its defenders. This intelligence had been gathered from a variety of sources which included signals intelligence, photographic reconnaissance flights and Dutch colonial officials. During the planning process the Allies believed that Tarakan was defended by a force of 4,000 men, including two infantry battalions. This estimate was considerably reduced shortly before the invasion when it was learned that one of the Japanese battalions had departed the island.
It was expected that Tarakan would be secured quickly. The planners anticipated that the operation would involve a short fight for the airfield followed by a consolidation phase during which the island's airfield and port would be developed. Significant fighting in Tarakan's interior was not foreseen, and no plans were developed for operations in areas other than the landing beaches, Tarakan Town and airfield. The planners did, however, correctly anticipate that the Japanese would make their main stand in an area other than the invasion beach and would not be capable of mounting a large counterattack.
The Allied plans also expected that Tarakan would be transformed into a major base within days of the landing. Under the pre-invasion planning it was intended that a wing of fighter aircraft would be based at Tarakan six days after the landing and this force would be expanded to include an attack wing nine days later and staging facilities for a further four squadrons of aircraft within 21 days of the landing. It was also expected that the 26th Brigade Group and its supporting beach group would be ready to leave Tarakan by 21 May and the RAAF units could be redeployed in mid-June after providing support for the landing at Balikpapan.
Tarakan was the Australian Services Reconnaissance Department's (SRD) first priority from November 1944. Prior to the invasion, I Corps requested that the SRD provide intelligence on Japanese positions in northern and central Tarakan. A five-man strong party landed on the island on the night of 25/26 April and reconnoitred the defences on Tarakan's north coast, though the operative who was assigned to the centre of the island became lost and did not reach this area. The SRD operatives withdrew from Tarakan on the night of 29/30 April and landed on the mainland of Borneo. They were unable to transmit the intelligence they had collected, however, as their radio set malfunctioned. Members of the party eventually landed within the Allied beachhead on Tarakan on 3 May to report to the 26th Brigade, but Whitehead was disappointed with the results of this operation and made no further use of the SRD during the battle.
Japanese plans.
In line with what had become the standard Japanese defensive doctrine by this stage of the war, Tarakan's coastal areas were considered impossible to defend for a prolonged period. As a result, plans for defending the island were focused on holding a redoubt in the interior of Tarakan. Several mutually supporting defensive positions located on hills and ridges were constructed. These fixed defences were used extensively during the battle. The Japanese did not conduct any large counter-attacks following the Allied invasion. Small parties of raiders were dispatched to infiltrate the Australian lines though.
Tarakan's defenders spent the months before the invasion constructing defensive positions and laying mines. The Japanese did not have any effective anti-aircraft weapons and lacked armoured vehicles and artillery. The garrison also had little ability to move forces around Tarakan, as it had few transport vehicles or engineers. The Imperial Japanese Navy and Japanese air units in South East Asia were weak, but posed a potential threat to the invasion force.
Opposing forces.
Allies.
The Allied force responsible for capturing Tarakan was centred around the very experienced Australian 26th Brigade Group of nearly 12,000 soldiers. The 26th Brigade had been formed in 1940 and had seen action in North Africa and New Guinea. The brigade's infantry component was the 2/23rd, 2/24th and 2/48th Battalions, also with much war experience. These battalions were joined by the 2/4th Commando Squadron and the 2/3rd Pioneer Battalion, which fought as infantry in this battle. The brigade group also included the 2/7th Field Regiment equipped with 24 25-pounder guns, a squadron from the 2/9th Armoured Regiment operating 18 Matilda tanks, a company of the 2/2nd Machine Gun Battalion, the 53rd Composite Anti-Aircraft Regiment and two engineer field squadrons. These combat units were supported by a large number of logistics and medical units, including the 2nd Beach Group whose role was to land supplies from the invasion fleet. While the 26th Brigade Group greatly outnumbered the known strength of Tarakan's Japanese defenders, the Allies committed this large force as their previous experience indicated that it would be difficult to defeat the Japanese force if it retreated into Tarakan's rugged interior.
The 26th Brigade Group was supported by Allied air and naval units. The air units were drawn from the Australian First Tactical Air Force (1 TAF) and United States Thirteenth Air Force and included fighter and bomber squadrons. The naval force was drawn from the United States Seventh Fleet and included several Royal Australian Navy warships and transports. Since the main objective of attacking Tarakan was to use the island's airstrip, the invasion force also included a large number of Royal Australian Air Force ground units, including No. 61 Airfield Construction Wing comprising No. 1 and No. 8 Airfield Construction Squadrons.
The force which landed on Tarakan included nearly a thousand United States and Dutch troops. The U.S. troops included the U.S. Army engineers who manned the invasion force's LCMs and LCVPs and the U.S. Army's 727th Amphibian Tractor Battalion, Co. A, who manned the LVTs and United States Navy Seabee detachments aboard the Landing Ship Tanks. The Dutch forces were organised into a company of Ambonese infantry commanded by Dutch officers and a civil affairs unit.
Japan.
At the time of the Allied landing, the Japanese force on Tarakan numbered approximately 2,200 men drawn from the Imperial Japanese Army and Imperial Japanese Navy. The largest unit was the 455th Independent Infantry Battalion which was commanded by Major Tadao Tokoi (). This was a second-rate unit that had been formed for garrison duties. It had few heavy weapons and no vehicles or horses for transport. The 455th Independent Infantry Battalion had arrived on Tarakan in December 1944. It comprised either 740 or just under 900 men. Another 150 Army support troops were also on Tarakan. A home guard unit comprising about 50 Indonesians had been recruited in early 1945 and was considered by the Japanese to be the most efficient such unit in the Borneo area. Major Tokoi directed the overall defence of Tarakan, though relations between the Army and Navy were poor.
The Imperial Japanese Navy's contribution to Tarakan's garrison comprised 980 seamen commanded by Commander Kaoru Kaharu. The main naval unit was the 600-strong 2nd Naval Garrison Force. This included a beach defence unit with around 250 men who manned several coastal defence guns and were also trained to fight as infantry. Other elements of the 2nd Naval Garrison Force included a ground defence company as well as small engineer, medical and supply units. The naval forces on the island also included