The '2nd Battle of Balikpapan', otherwise 'Oboe II', marked the conclusion of the 'Oboe' campaign for Allied (primarily Australian) forces to retake the most important part of the island of Borneo from the Japanese (1/21 July 1945).
The landings took place on 1 July 1945 as Major General Edward J. Milford’s Australian 7th Division, comprising Brigadier F. O. Chilton’s 18th Brigade, Brigadier Ivan N. Dougherty’s 21st Brigade and Brigadier Kenneth W. Eather’s 25th Infantry Brigades, with a small number of Dutch East Indian troops, made the 'Oboe II' amphibious landing a short distance to the north of Balikpapan. The Allied invasion fleet consisted of around 100 ships. The landing had been preceded by heavy bombing and shelling by Australian and US air and naval forces. The Allied force totalled 33,000 men, and the Japanese force, commanded by Rear Admiral Michiaki Kamada, numbered between 8,400 and 10,000 men, of which between 3,100 and 3,900 were combatants. After the initial landing, the Allies secured the town and its port, and then advanced along the coast and into the hinterland, capturing the two Japanese airfields. Major combat operations concluded around 21 July, but were followed by mopping-up operations, which lasted until the end of the war on 15 August August. Australian troops remained in the area until a time early in 1946.
Located 1,292 miles (2241 km) to the north-west of Darwin in Australia’s Northern Territory, Balikpapan lies on the south-eastern coast of Borneo, and its significance lay in its oil production and port facilities. Before World War II, the area had an annual production of 1.8 million tons of oil. The port, lying inside Balikpapan Bay, comprised seven piers and a large number of warehouses, and was serviced by well-developed road network. At its mouth, the bay is 1 mile (1.6 km) wide, and was suitable for medium-sized ships. To the south of the port, an oil refinery with 40 storage tanks and a cracking plant lay along a steep ridge, separating the port from the European suburb of Klandasan, which looked out on the open sea from the cape on the eastern part of the bay. Two roads fanned out from Balikpapan town, one to the north-east to Samarinda (dubbed the 'Milford Highway' by the Australians) and the other was the 'Vasey Highway' extending to the south along the coast towards Samboja. The refinery in Balikpapan was supplied with oil from fields around Samboja and Sangasanga to the north-east.
To the east of the cape, the narrow coastal strip was serviced by a road that extended eastward from Klandasan to Stalkoedo, Sepinggang, Batakan Besar, Manggar and Samboja. and in the process crossing many rivers and streams. This road sat on a thick sandy strip of ground, just inland from the beach. The ground around the coast is largely flat, although there are some low hills which rise sharply farther inland to heights of some 700 ft (210 m). While the area around the town and coast was largely open, the interior was heavily covered with thick rain forest. The dense vegetation limited cross-country movement, although the rivers and streams were partially navigable. Two airfields had been established to the east of Balikpapan around Sepinggang and Manggar. Manggar was the larger of the two, consisting of two runways that had been graded out of coral. At the time of the Allied landings, the airfield had been badly damaged by bombing, while the second and smaller airfield at Sepinggang had also been rendered unserviceable.
Balikpapan lies 1° south of the equator and has a tropical rain forest climate. The maximum temperature for most days in south-eastern Borneo is between 22 and 30° C (72 and 86° F), and the relative humidity is consistently high, ranging from 74 to 93%. Monthly rainfall is fairly constant, averaging 6.9 in (18 cm) in July. Allied intelligence estimates assessed that the July to September period represented that best period for military operations. In terms of cloud cover, July is generally clear and visibility is assessed as generally good. Wind speeds average 7 mph (11 km/h) with south-south-westerly generally the most prevalent during the period between May and November.
Before World War II, Balikpapan was under Dutch control as part of the Netherlands East Indies. The Japanese occupied British Borneo and the Netherlands East Indies in the period between late 1941 and early 1942, and Balikpapan itself was seized on 25/27 January 1942 in the '1st Battle of Balikpapan'. British and Dutch forces attempted to resist, but were quickly overwhelmed, though only after they had destroyed or damaged the oil facilities and other important infrastructure. The destruction of these facilities led to harsh reprisals against civilians, particularly at Balikpapan, whose seizure led to the execution of the entire European population of between 80 and 100 persons. The Japanese repaired the oil facilities, and in 1943 and 1944, Borneo became one of Japan’s main sources of crude and heavy fuel oil: in 1943, Balikpapan provided 3.9 million barrels of fuel oil to the Japanese war effort.
Throughout 1943 and 1944 the Allies attempted to reduce Japanese oil production at Balikpapan with air power. The first strategic bombing raids began in October 1943, and were undertaken by US Consolidated B-24 Liberator four-engined heavy bombers, flying 17 hours from bases around Darwin. More raids took place in December 1943 and January 1944. During the early months of 1944, Royal Australian Air Force Consolidated Catalina twin-engined flying boats carried out a series of highly successful mining operations, which reduced the output of Balikpapan’s facilities by an estimated 40%. Late in September and early in October 1944, the US 13th Army Air Force and 5th Army Air Force, commanded by Major General St Clair Street and Major General Ennis C. Whitehead respectively, began long-range raids from Noemfoor island. The first two raids suffered heavy losses for lack of escort fighters and inflicted minimal damage; after a brief pause and a change of tactics by the US airmen, however, the last three raids resulted in heavy damage to the refineries and the destruction of most of the Japanese aircraft defending Balikpapan. Combined with Allied operations along Japanese sea lanes of communication, this effectively isolated Japan from Balikpapan’s oil supply line. The Japanese decided not to repair the damaged facilities, and those that remained were used only for local supply and indeed, after October 1944, no more Japanese oil tankers were sent to Balikpapan. This diverted Japanese efforts to the oilfields of Sumatra.
The Japanese advance in the Pacific theatre had been halted, by a time early in 1943, by Australian troops on New Guinea and US troops on Guadalcanal island in the Solomon islands group, after which the Allies went on the offensive, advancing through New Guinea and the Solomon islands group toward the Philippine islands group. Throughout 1944, the Allies began planning to retake Borneo. The General Headquarters of General Douglas MacArthur’s South-West Pacific Area was responsible for planning the operation, but as a result of the commitment of US forces to the recapture of the Philippine islands group, the task of retaking Borneo was allocated primarily to Australian ground forces, which effected landings at Tarakan, Labuan and Balikpapan. Originally, MacArthur had intended to use Borneo as a stepping stone in his 'Montclair' plan for the recapture of Java, but this operation was later cancelled and responsibility for the Netherlands East Indies was transferred to Admiral the Lord Louis Mountbatten’s British South-East Asia Command. In the planning phase for the Borneo operations, the commander of the Australian Military Forces, General Sir Thomas Blamey, recommended against the landing at Balikpapan, believing that it would serve no strategic purpose, but after much consideration the Australian government agreed to provide forces for this operation. The US Joint Chiefs-of-Staff also had concerns about the strategic necessity of the Balikpapan operation, but MacArthur appears to have manipulated both the Australian government and the Joint Chiefs-of-Staff into approving the capture of Balikpapan. The stated purpose of the operation was to secure the port and oilfields in the area, and to establish a base from which to launch future operations. Additionally, Netherlands East Indies governmental control would be re-established.
The Japanese began their preparations to defend against Allied landings in Borneo during 1944. The garrison forces were reorganised and an operational command was created as Lieutenant General Masao Baba’s 37th Army. Early in 1945, this army began a redeployment to boost the defence of Borneo’s western coast. The Japanese strength for the defence of the Balikpapan area in 1945 was between 6.400 and 10,000 men of which, as noted above, between 3,100 and 3,900 were combatants. About 1,500 infantry and field artillery men were situated in the area of Balikpapan and Manggar, together with 1,500 anti-aircraft gunners. Base troops made up the rest of the number, along with between 1,100 and 4,500 armed Japanese, Formosan and Indonesian civilian labourers. Another 1,500 troops were some 60 miles (100 km) away at Samarinda. The main Japanese units were Rear Admiral Michiaki Kamada’s 22nd Naval Base Force and elements of Major General Hyoe Yamamura’s 71st Independent Mixed Brigade. The 22nd Naval Base Force's st Battalion was located around Klandasan and the Sumber river while its 2nd Battalion was positioned around Batuchampar. Two other companies were located in the area of Penadjam. The Imperial Japanese army’s 454th Battalion had also been deployed to the Manggar area after being redeployed from Tarakan in March 1945. The Japanese holding Balikpapan town comprised the 2nd Garrison Force of armed labourers, base troops, artillerymen and a small number of naval infantrymen as well as the elements of the 454th Independent Battalion. These troops were characterised bh varying levels of training and their morale had been adversely affected by weeks of preliminary bombardment. They were well equipped, however, with large-calibre weapons, but were short of lighter weapons. As a result, they were limited largely to static warfare.
As a result of the Allied interdiction of sea lanes throughout the Pacific, Japanese troops on Borneo had found themselves increasingly isolated, and by the end of 1944 supply shipments had essentially ended. Food and supplies dwindled and units were forced to commence subsistence operations as the majority of troops began to suffer from malnutrition. Sanitation was also poor and as a result of their limited medical supplies many Japanese troops became non-battle casualties. Even sp, the Balikpapan area was well supported by artillery in the form of 18 coast-defence guns concentrated around the ridges overlooking Balikpapan, along with 26 heavy guns and 78 medium and light anti-aircraft guns. These weapons were orientated to defend the airfield, port and Balikpapan town itself. The defences in the area included an anti-tank ditch between 12 and 14 ft (3.65 and 4.25 m) wide along the coast between Stalkoedo and Sepinggang, supplemented by another ditch round Klandasan. The beaches were dotted with Dutch-built concrete pillboxes, and the Japanese had dug a trench complex on the ridges overlooking the town. The seaward approach to Klandasan was defended by an underwater obstacle consisting of poles and barbed wire extending between Klandasan and Manggar, and this was supplemented by a large number of naval mines around the coast.
The operation to retake Balikpapan was designated 'Oboe II' by the Allies, who assigned 33,000 men to the task. The main ground forces, amounting to 21,000 men were drawn from Milford’s Australian 7th Division, a veteran 2nd Australian Imperial Force formation consisting of three infantry brigades together with supporting artillery, armour, engineer and logistics units. The Australian 7th Division had seen action earlier in the war in the Middle East and in New Guinea, but had been resting on the Atherton Tablelands of Queensland when it was assigned to the operation. The division’s formation- and unit-level command teams were all very experienced, but as a result of the high turnover of Australian army personnel in 1943/44, many of its more junior personnel had not yet seen action. Tank support was provided by the 1st Armoured Regiment, equipped with Matilda II infantry tanks in several variants. Naval support was drawn from Vice Admital Thomas C. Kinkaid’s US 7th Fleet, and air support came from Air Commodore Frederick R. W. Scherger’s Australian 1st Tactical Air Force and the US 13th Army Air Force, now commanded by Major General Paul B. Wurtsmith. Three US Navy escort carriers were also assigned to provide fighter support as the airstrip at Tarakan was not yet operational, and weather conditions hampered the provision of fighter support from the Philippine islands group. A small number of Dutch East Indian troops (one company of the 1st Battalion) was also assigned to the operation.
Planning teams from all branches of the Australian and US armed services gathered at Morotai island to start the planning of the operation, about 26 April. Knowledge of a shipping shortage hampered the preliminary movement of troops, and a lack of co-ordination and scheduling meant that tactical-level planning and battle preparation were carried out hastily. The first combat troops began to embark at Townsville in Queensland early in May, but planners from the combat formations assigned to the operation did not reach Morotai until 13 June. In determining the location of the landing, the naval team suggested the area of Manggar as the water was deeper in this area, but the beach was deemed unsuitable and a landing at Manggar would have required the ground forces to advance 10 miles (16 km) through difficult terrain to reach their primary objective around Balikpapan. Farther to the west, around Stalkoedo and Klandasan, the beach was more suitable for a large-scale landing, but this was the area in which most of the Japanese defences were located; additionally, the water in this area was not as deep, and as a result the supporting cruisers would have to stand farther out to sea, which would reduce the accuracy of their gun fire when engaging shore targets. The approach was also covered by minefields and other obstacles. Ultimately, Milford chose to land at three beaches across a 2,000-yard (1830-m) front in the area occupied by the main Japanese forces, reasoning that the shorter approach march outweighed the risks, which would be reduced by comprehensive aerial and naval bombardments before the landing.
The continued unserviceability of the airfield on Tarakan meant that air support was provided by Australian and US aircraft based in the southern part of the Philippine islands group. Air operations began 20 days before the landing, while minesweepers began clearing safe lanes and anchorages five days later. These operations were undertaken inside the range of Japanese coastal guns, and in order to protect the minesweepers, naval gunfire and aerial bombardment were employed to suppress and finally to neutralise the Japanese guns. Japanese torpedo boats attacked the minesweepers on 24 June but met with no success. Even so, three minesweepers were lost during the clearance operations.
While the assigned troops were moving from Queensland to the staging base at Morotai, the Allies began enacting a deception plan to decoy Japanese attention from the intended landing area. This plan included the dissemination of disinformation among the local population, and the implementation of supposed preparatory operations in locations away from the intended area. Advance force operations included small parties of special forces landing to carry out reconnaissance, while minesweeping and obstacle-clearance operations began 16 days before the assault. The pre-invasion bombardment expended more than 3,000 tons of bombs, 7,361 rockets, 38,052 shells and 114,000 small arms rounds, and as a result most of the Japanese field guns were destroyed and the shore defences severely degraded. The focus of the Allied air campaign from a time late in May was Japanese airfields throughout the Netherlands East Indies, as well as anti-aircraft facilities; attacks were also made on oil facilities around Samarinda by RAAF aircraft in contravention of an initial order not to target these facilities.
The Allied fleet of more than 100 mainly US and Australian ships began to form round Morotai island on 17 June. After the completion of landing rehearsals, the fleet departed during the afternoon of 26 June, traversing the Strait of Macassar. On 29 June, the faster naval vessels earmarked to carry out the pre-landing bombardment separated from the convoy. Meanwhile, US underwater demolition teams worked to create gaps in the off-shore obstacles: this work was carried out under heavy fire. Several of the supporting Allied vessels were damaged and the operations were concluded without completely clearing the obstacles from the central landing beach, which was designated Yellow Beach. In total about 3,300 ft (1005 m) of the landing beach was cleared, while 2,460 ft (750 m) of neighbouring beaches were also cleared as part of deception operations. Early on 1 July, the convoy reached the assembly area about 8 miles (13 km) to the south-east of Klandasan, after which a heavy naval and aerial bombardment concentrated on the beaches around Klandasan. A total of 63 Consolidated B-24 Liberator four-engined heavy bombers, as well as five cruisers and 14 destroyers, were committed to this action: 17,250 shells were expended by the naval bombardment group in this effort.
Meanwhile, the assault troops on board nine tank landing ships headed for the transport area, where they were transferred to smaller landing craft, including Alligator tracked landing vehicles, DUKW amphibious trucks and vehicle/personnel landing craft. These craft were crewed by US personnel, mainly of the 672nd and 727th Amphibian Tractor Battalions and the 593rd Engineer Boat and Shore Regiment. Under cover of the bombardment, the landing craft began to approach the shore in several waves. When they were 1,300 yards (1190 m) from the shore, the naval bombardment came to an end. The landing craft lowered their ramps as they beached just before 09.00. The landing was carried out on a two-brigade front: Chilton’s 18th Brigade landed the 2/10th and 2/12th Battalions on the left at Red and Yellow Beaches, while Dougherty’s 21st Brigade landed the 2/27th Battalion landed on the right at Green Beach. The division’s third major element was the 25th Brigade, and this initially remained embarked as the floating reserve. The assault troops were landed at the wrong place as a result of the poor visibility stemming from the pre-landing bombardment, and a failure to clear all of the beach obstacles. As a result, two of the three assault battalions landed too far to the left, and troops from each battalion became intermixed with others, causing some confusion. Despite this, the landing was opposed only by a small volume of fire, and within 15 to 20 minutes the assault troops had established a beach-head. The landing force suffered no casualties during this first part of 'Oboe II'.
After the beach maintenance area had been secured, the 18th Brigade was tasked with capturing the high features to the north of Klandasan, which otherwise blocked the advance toward Balikpapan town, while the 21st Brigade was tasked with advancing along the coast road to capture the airfields at Sepinggang and Manggar. During the fighting around Klandasan, the 2/10th Battalion attacked a feature dubbed Parramatta Ridge, which was strongly fortified with pillboxes, tunnels, land mines and booby traps. As a result of a last-minute diversion and communications issues, the battalion’s fire support was unavailable, and the tanks that had been assigned to support them broke down. Even so, the battalion’s commanding officer, Lieutenant Colonel Tom Daly, pressed home the attack despite the threat of of heavy casualties. The initial infantry assault on Hill 87 was took place throughout the morning, and stalled as Japanese resistance grew; the Australians became pinned below the summit and just before 12.00 two supporting tanks of the 1st Armoured Regiment came forward, suppressing Japanese fire and assisting the infantry to capture the position by 12:40 pm. After this, the indirect fire support, except for the divisional machine guns, was restored. Japanese fire from neighbouring positions was suppressed, enabling a company assault on the final objective. By 14.00, the Australian infantrymen had captured Parramatta Ridge.
Meanwhile, the 21st Brigade had come up against heavy resistance after initially advancing against only desultory artillery and mortar fire. The Australian ground troops were well provided with direct and indirect fire support, and with the support of tanks, flamethrowers, mortars and other fire support weapons, by the end of the first day had extended their beach-head by 2,100 yards (1920 m). The work of marking out the beaches and organising the troops as they arrived on the beach, as well as controlling the unloading of stores, was undertaken by a specially trained unit, the 2nd Beach Group, which landed in the second wave. Shortly after landing, it was found that the LSTs could not land their stores over the beaches, and DUKWs were therefore used instead to offload stores and land them.
The fighting for the high ground around Klandasan continued throughout 2 July as the Japanese, largely of the 2nd Garrison Force and elements of the 454th Independent Battalion, resisted strongly. The Australian engineers worked to destroy large numbers of Japanese tunnels, as well as to neutralise thousands of land mines and booby traps. The 25th Brigade landed at this time, while the 21st Brigade pushed farther to the east with engineers supporting the multiple river crossings. The 2/14th Battalion captured Sepinggang airfield, using indirect fire support as much as possible to minimise its own casualties, the 2/27th Battalion secured the area around Stalkoedo, and the 2/16th Battalion also took several features.
On the following day, 3 July, Eather’s 25th Brigade relieved the 18th Brigade while the latter secured Balikpapan town and its harbour, and the 25th Brigade advanced inland along the 'Milford Highway'. By the end of the day, the Australian beach-head had been extended to 5 miles (8 km), and the 21st Brigade had reached Manggar airfield. Elements of the 454th Independent Battalion still occupied strong positions on the high ground overlooking the airfield, however, and were able to call down heavy concentrations of mortar and artillery fire. The Australians captured the airfield on 4 July, but were then checked for several days after coming up against Japanese artillery and mortar fire. Tanks were landed around the Manggar Besar river, but two were knocked out by Japanese fire. Naval and air support was called in, and over the course of several days the gun positions were captured.
After landing, the 25th Brigade assumed a holding role in the centre of the beach-head until 3 July, when it took over from the 18th Brigade, which went into reserve, but remained around Balikpapan town to continue mopping-up operations. The 25th Brigade then began pushing inland from the urban area toward Batuchampar, some 10 miles (16 km) from the initial landing beaches.
On 5 July, the 2/9th Battalion and the 2/1st Pioneer Battalion, supported by elements of the 2/7th Cavalry Commando Regiment as well as artillery and tanks, were landed at Panadjam by LVTs and LCMs to clear the western shore of Japanese artillery before the Allies opened the port. The 2/9th Battalion sent patrols to Nanang and the Sesumpu river before continuing down the Riko river and landing another patrol which exploited inland toward the Parehpareh river. Meanwhile, the 2/1st Pioneer Battalion landed at several spots, including Teloktebang, Djinabora and Tempadung, before advancing overland to Pamaluan. Japanese opposition was limited, and the area round Panadjam was cleared within two days. However, heavy fighting took place along the 'Milford Highway' on 5/6 July as part of a Japanese battalion attempted to block the Australian advance on Batuchampar. The Japanese employed a variety of delaying tactics in their efforts to slow the Australians, and used the thick jungle to their advantage. The Australians brought up tanks equipped with flamethrowers, and called in a heavy artillery barrage to clear the firmly entrenched defenders; more than 8,000 rounds were expended in this effort.
By 9 July, the two forward Japanese battalions had been largely destroyed, and the remnants were withdrawing from the eastern coast. The 21st Brigade continued its advance toward Samboja, and patrols also ranged toward the 'Milford Highway' to establish contact with the 25th Brigade. Kamada, the Japanese commander, had established his headquarters around Batuchampar by this time, and the Japanese rearguard began tp pull back to the main defensive position 3 miles (4.8 km) inland at Batuchampar, where Kamada’s third battalion was digging in. Meanwhile, the landing beaches were being improved with the construction of several docks by the US 11th Naval Construction Battalion, to enable two LSTs to be unloaded at a time. On 10 July, the Allies opened another beach, designated Brown Beach, round the southern part of the bay; the protected waters there greatly increased the volume of supplies that could be brought in, allowing eight LSTs to dock at the same time.
Over the course of a fortnight, Allied artillery and aircraft steadily reduced the Japanese position along the 'Milford Highway', while the 25th Brigade probed for the Japanese flanks in an attempt to encircle them. Meanwhile, patrols of the 2/7th Cavalry Commando Regiment and the Dutch company were sent along the flanks and to remote areas to gather intelligence. By 21 July, the encirclement of the Japanese defensive position was almost complete and the surviving Japanese began a withdrawal that was conducted in good order, and the Australians noted the skill and determination with which the Japanese sited and held their defensive positions during this time. The Australians assessed that the Japanese would seek to establish a new defensive position round Samarinda, but Milford determined that the strategic situation did not require attacking this position. Following this, the Australians began deep patrolling operations. The 2/27th Battalion advanced along the 'Vasey Highway', ranging as far as Samboja.
Major operations had ceased by 21 July, when the Japanese abandoned Batuchampar and Manggar, although small-scale clashes continued until the end of the war on 15 August. The majority of the Japanese withdrew to the north-east before eventually turning to the west and marching across Borneo to Kuching or Bandjermasin. However, men of the 22nd Special Base Force attempted to break into the port facilities around Balikpapan in August from the western side of the bay, and several minor actions were fought during this time.
The Australian 7th Division’s casualties were significantly lighter than they had been in previous campaigns: 229 Australians were killed and 634 wounded, while at least 2,032 Japanese were killed and another 63 taken prisoner.
The 'Oboe II' operation to secure Balikpapan was Australia’s largest and last amphibious operation of World War II. The battle was one of the last of the war, beginning only a few weeks before the atomic bombings of Hiroshima and Nagasaki and the Soviet invasion of Manchuria effectively ended the war. Japan surrendered while the Australians were combing the jungle for stragglers. In this regard, and in light of the strategic situation which had effectively negated many of the stated Allied reasons for the operation, it has been suggested that the operation exercised no effect on the course of the war and was 'strategically dubious'. Moreover, it had been argued that the cancellation of the 'Oboe IV' operation to retake Java negated the need for 'Oboe II' and that the decision to continue with the operation was probably influenced by the perceived importance of Balikpapan’s oil facilities.
Despite the early capture of the airfields at Sepinggang and Manggar, it was not until 15 July that the first RAAF Supermarine Spitfire single-engined fighter-bombers began operations there, and ultimately the airfields could not be used for bombing operations. Additionally, much of the port area and oil-production facilities had been heavily damaged by the pre-invasion bombardment and by Japanese sabotage, rendering them useless to the Allies in the short term. Politically, the damage inflicted on the infrastructure strained the relationship between the Australians and the returning Netherlands East Indies government. Additionally, the oilfields that supplied the damaged refineries (round Samboja and Sangasanga) remained in Japanese hands until the end of the war, effectively denying the Allies what little benefit they had gained in securing the refineries.
As a result of the limited strategic reasons for the operation, it has been suggested that the operation was undertaken largely for political reasons, as MacArthur wished to 'show the Dutch government that he had attempted to recover part of its territory…' but ultimately it did not affect the outcome of the war. Even so, while the operation might have been of only doubtful strategic value it was skilfully conducted at the tactical level. A key element of the operation’s success from the Australian perspective was the logistic support provided by the USA, particularly in relation to the shipping that was required to transport the troops, stores and equipment for the operation. In comparison with the concurrent operations which Lieutenant General Sir Vernon Sturdee’s Australian 1st Army were fighting in New Guinea, particularly around Aitape and Wewak, the operations of Lieutenant General Sir Leslie Morshead’s Australian I Corps in Borneo received considerably more resources in terms of air, naval and transport support.
After the surrender of Japn, the three Australian brigades were committed to occupation duties until about February 1946. The 21st Brigade was detached to Makassar to accept the surrender of the Japanese forces on Celebes island, release prisoners of war and maintain civil order. The 25th Brigade detached elements to occupy Samarinda, Bandjermasin, Tanahgrogot, and Pontianak.