Battle of Borneo ( 1941 – 42 ) " For campaigns on eastern Borneo , see Battle of Tarakan ( 1942 ) and Battle of Balikpapan ( 1942 ) . " 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 Kingdom 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 . Historical context . In 1941 , Borneo was divided between the Dutch East Indies and British protectorate s ( North Borneo , Sarawak and Brunei ) and crown colonies ( Labuan ) . The so - called " White Rajahs " , the Brooke family , had ruled Sarawak , on the northwest of Borneo , for almost a century , first as Raja hs under the Sultanate of Brunei ( a by then tiny but once powerful state entirely enclosed within the borders of Sarawak ) , and from 1888 as a protectorate of the British Empire . The northeast of the island comprised North Borneo , since 1882 another British protectorate under the British North Borneo Company . Offshore lay the small British crown colony of Labuan . The rest of the island — collectively known as Kalimantan — was under Dutch control . The Netherlands were invaded by Nazi Germany in 1940 . However , Free Dutch forces — mainly the Royal Netherlands Navy and the 85 , 000 - strong Royal Netherlands East Indies Army ( KNIL , including a small air service ) — fought on , spread throughout the Dutch East Indies , and by December 1941 under an embryonic and somewhat chaotic joint allied command which became the short - lived American - British - Dutch - Australian Command ( ABDACOM ) . Background to the conflict . The Tripartite Pact — between the three Axis Powers of Germany , Japan and Italy — guaranteed mutual support , and this paid off for Japan in July 1941 when the Nazis forced Vichy France to cede French Indo - China ( now modern Vietnam , Laos and Cambodia ) to Japan . This gave Japan land access to the Chinese mainland where it had long been engaged in military intervention and , since 1937 , had been fighting a full - on war of invasion against the temporarily allied forces of the Kuomintang and the Communist Party of China . It also gave Imperial Japan a seaboard facing Sarawak and North Borneo across the China Sea . Japan turned its eyes from the war in China and towards strategic targets in the Pacific and the Dutch East Indies . In December that year , Japan struck out against U . S . possessions in Hawaii and the Philippines , declaring war on the U . S . and finally precipitating Germany ' s official declaration of war on America according to the Pact . With its rich petroleum exploitation capacity , for instance at Tarakan , Balikpapan and Banjarmasin , Borneo was a prime target for Japan , and a very poorly guarded one . Chronically short of natural resources , Japan needed an assured supply of fuel in order to flex its muscles and achieve its long term goal of becoming the major power in the Pacific region . Borneo also stood on the main sea routes between Java , Sumatra , Malaya and Celebes . Control of these routes were vital to securing the territory . Defence in Sarawak and North Borneo . The main objectives were the oilfields at Miri in Sarawak region and Seria in Brunei . The oil was refined at Lutong near Miri . Despite rich oil supplies , the Sarawak region had no air or sea forces to defend it . Only in late 1940 did Air Chief Marshal Sir Robert Brooke - Popham order the 2nd Battalion , 15th Punjab Regiment , a heavy gun battery from the Hong Kong - Singapore Royal Artillery , and a detachment of 35th Fortress Company ( Royal Engineers ) to be positioned at Kuching . They numbered about 1 , 050 men . In addition , the Brooke White Rajah government also organised the Sarawak Rangers . This force consisted of 1 , 515 men who were primarily Iban and Dayak tribesmen . Altogether these forces were commanded by British Lieutenant Colonel C . M . Lane and was known as " SARFOR " ( Sarawak Force ) . After having heard of the attack on Pearl Harbor , on 8 December 1941 , the Brooke government instructed that the oilfields at Miri and Seria and refinery at Lutong be quickly demolished . Defence in Singkawang and Pontianak ( Dutch East Indies ) . The Dutch forces had an important airfield at Singkawang called " Singkawang II " , which was defended by about 750 Dutch troops . On 25 November five Brewster F2A Buffalo fighter planes arrived for local defence followed in the beginning of December by Glenn Martin B - 10 bombers . The Dutch Naval Aviation Group GVT - 1 with three Dornier Do 24 K flying boat s was located in Pontianak along with a KNIL garrison , commanded by Lieutenant Colonel Dominicus Mars , numbering approximately 500 men . Dutch forces in West Borneo consisted of the following units : The town of Pontianak was finally occupied by the Imperial Japanese forces on 29 January 1942 . Japanese landing and the battle . The main Japanese force — led by Major General Kiyotake Kawaguchi — consisted of units from Canton , southern China : On 13 December 1941 , the Japanese invasion convoy left Cam Ranh Bay in French Indochina , with an escort of the cruiser ( Rear - Admiral Shintaro Hashimoto ) with the destroyers of the 12th Destroyer Division , , , and , submarine - chaser " Ch 7 " and the aircraft depot ship " Kamikawa Maru " . Ten transport ships carried the Japanese 35th Infantry Brigade HQ under the command of Major - General Kiyotake Kawaguchi . The Support Force — commanded by Rear - Admiral Takeo Kurita — consisted of the cruisers and and the destroyers and . The Japanese forces intended to capture Miri and Seria , while the rest would capture Kuching and nearby airfields . The convoy proceeded without being detected and , at dawn on 16 December 1941 , two landing units secured Miri and Seria with only very little resistance from British forces . A few hours later , Lutong was captured as well . Dutch Glenn Martin B - 10 bombers made attacks on Japanese shipping at Miri on 17 , 18 and 19 December from their base ' Singkawang II ' . The Dutch bombers retired ( ment to be temporarily ) to Sumatra on 23 December since ' Singkawang II ' airfield was discovered by the Japanese and the first bombing attack against the airfield had been carried out on 22 December . On 24 and 28 December B - 10 bombers from a different unit flew missions against Kuching from Singapore , Sembawang . In the evening of 23 December Dutch submarine K - XIV hit four out of six Japanese transport ships at Kuching with torpedoes ( the cargo ship sank while two other ships where damaged ' moderate ' and one ship sustained light damage ) . On the night of 24 – 25 December Dutch submarine HNLMS K XVI sank the Japanese submarinechaser ' Sagiri ' 30 Miles north of Kuching . K - XVI was lost the following day by a torpedo from Japanese submarine I66 . Meanwhile , on 31 December 1941 , the force under Lieutenant Colonel Watanabe moved northward to occupy Brunei , Labuan Island , and Jesselton ( now called Kota Kinabalu ) . On 18 January 1942 , using small fishing boats , the Japanese landed at Sandakan , the seat of government of British North Borneo . The North Borneo Armed Constabulary , with only 650 men , hardly provided any resistance to slow down the Japanese invasion . On the morning of 19 January , Governor Charles Robert Smith surrendered British North Borneo and was interned with other staff . After securing the oilfields , on 22 December , the main Japanese forces moved westwards to Kuching . The Japanese airforce bombed Singkawang airfield to prevent a Dutch attack . After escorts drove off a lone Dutch submarine , the Japanese task force entered the mouth of the Santubong river on 23 December . The convoy arrived off Cape Sipang and the troops in twenty transports , commanded by Colonel Akinosuke Oka , landed at 04 : 00 the next morning . Although 2nd Battalion , 15th Punjab Regiment , resisted the attack , they were soon outnumbered and retreated up the river . By the afternoon , Kuching was in Japanese hands . At about 16 : 40 on 25 December , Japanese troops successfully captured Kuching airfield . The Punjab regiment retreated through the jungle to the Singkawang area . After Singkawang was secured as well on 29 December , the rest of the British and Dutch troops retreated further into the jungle southward trying to reach Sampit and Pangkalanbun , where a Dutch airfield at Kotawaringin was located . South and central Kalimantan were taken by the Japanese Navy following attacks from east and west . After ten weeks in the jungle - covered mountains , Allied troops surrendered on 1 April 1942 .