Battle of Surabaya The Battle of Surabaya was fought between pro - independence Indonesian soldiers and militia against British and British Indian Troops as a part of the Indonesian National Revolution . The peak of the battle was in November 1945 . Despite fierce resistance , British Indian troops managed to conquer Surabaya , the second - largest city in Indonesia . The battle was the heaviest single battle of the revolution and became a national symbol of Indonesian resistance . Considered a heroic effort by Indonesians , the battle helped galvanise Indonesian and international support for Indonesian independence . 10 November is celebrated annually as Heroes ' Day ( " Hari Pahlawan " ) . By the time the Allied forces arrived at the end of October 1945 , the " pemuda " ( ' youth ' ) foothold in Surabaya City was described as " a strong unified fortress " . Ferocious fighting erupted when 6 , 000 Indian troops landed in the city to evacuate European internees . Following the killing on 30 October of the British commander , Brigadier A . W . S . Mallaby , the British retaliated with a punitive sweep that began on 10 November , under the cover of air attacks . Although the European forces largely captured the city in three days , the poorly armed Republicans fought for three weeks , and thousands died as the population fled to the countryside . Despite the military defeat suffered by the Republicans and a loss of manpower and weaponry that would severely hamper Republican forces for the rest of the revolution , the battle and defence mounted by the Indonesians galvanised the nation in support of independence and helped garner international attention . For the Dutch , it removed any doubt that the Republic was not simply a gang of collaborators without popular support . It also had the effect of convincing Britain that wisdom lay on the side of neutrality in the revolution ; within a few years , in fact , Britain would support the Republican cause in the United Nations . Background . On 17 August 1945 , Soekarno and Hatta declared the independence of Indonesia in Jakarta , two days after the Japanese emperor ' s surrender in the Pacific . As the news about the independence declaration spread throughout the archipelago , ordinary Indonesians felt a sense of freedom that led most to regard themselves as pro - Republican . In the following weeks , power vacuums existed , both from outside and within Indonesia , creating an atmosphere of uncertainty , but also one of opportunity . On 19 September 1945 , a group of Dutch internees supported by the Japanese raised the Dutch flag outside the Hotel Yamato ( formerly Hotel Oranje , now Hotel Majapahit ) in Surabaya , East Java . This provoked nationalist Indonesian militia , who overran the Dutch and Japanese , and tore off the blue part of the Dutch flag , changing it into the Indonesian flag . The leader of the Dutch group , Mr Ploegman , was killed because of mass anger . The senior Japanese commander in Surabaya , Vice Admiral Shibata Yaichiro , supported the Republicans and gave Indonesians ready access to arms . On 3 October , he surrendered to a Dutch Navy captain , the first Allied representative to arrive . Yaichiro ordered his forces to hand over their remaining weapons to the Indonesians . The Indonesians were to hand them to the allies , but neglected to do so . British forces brought in a small Dutch military contingent which it termed the Netherlands Indies Civil Administration ( NICA ) . The British became worried about the increasing boldness and apparent strength of the nationalists , who attacked demoralised Japanese garrisons across the archipelago with rudimentary weapons such as bamboo spears in order to seize their arms . The main goals of British troops in Surabaya were the seizing of weapons from Japanese troops and Indonesian militia , taking care of former prisoners - of - war ( POW ) , and sending the remaining Japanese troops back to Japan . In September and October 1945 a series of incidents took place involving pro - Dutch Eurasians , and atrocities were committed by Indonesian mobs against European internees . In late October and early November , the leadership of the mass Muslim organisations Nahdlatul Ulama and Masyumi , declared that war in defence of the Indonesian fatherland was Holy War , and thus an obligation for all Muslims . " Kyai " and their students , began to stream into Surabaya from Islamic boarding schools throughout East Java . The charismatic Bung Tomo made use of local radio to encourage an atmosphere of fanatical revolutionary fervour across the city . Six thousand British Indian troops were sent into the city on 25 October to evacuate European internees and within three days fighting began . After heavy fighting between the British Indian forces and around 20 , 000 Indonesian armed regulars of the newly formed People ' s Security Army ( TKR ) and mobs of 70 , 000 – 140 , 000 people , the British flew in the influential President Sukarno , Vice President Hatta and his ministers Amir Sjarifuddin , and a ceasefire was achieved on 30 October . Prelude . On 26 October 1945 , Brigadier A . W . S . Mallaby reached an agreement with Mr Suryo , the Republic of Indonesia ' s governor of East Java , that the British would not ask Indonesian troops / militia to hand over their weapons . An apparent misunderstanding about the agreement between British troops in Jakarta ( led by Lieutenant General Sir Philip Christison ) and Mallaby ' s troops in Surabaya was to have serious ramifications . Initially British troops were 6 , 000 - strong lightly armed Indian soldiers from 49th Infantry Brigade of the 23rd Indian Division . When the battle reached its peak , the British sent additional troops which consisted of 24 , 000 fully armed soldiers from the 5th Indian Division , 24 Sherman tanks , 24 armed aircraft , 2 cruiser s and 3 destroyer s . Indonesian forces consisted of 20 , 000 soldiers from the newly formed " Tentara Keamanan Rakyat " ( TKR ; People ' s Security Troops ) and an estimated 100 , 000 – 120 , 000 irregulars . TKR was formed by the former members of " Peta " , a semi - military organisation during Japanese occupation . The irregulars consisted of pro - Independence mob , armed with rifles , swords , and bamboo spears . Some of their weapons were taken from surrendered Japanese troops . Battle . Beginning . On 27 October 1945 , a British plane from Jakarta dropped leaflets over Surabaya urging all Indonesian troops and militia to surrender their weapons . The leaders of the Indonesian troops and militia were angered , seeing it as a breaking of the agreement reached with Mallaby earlier . On 28 October 1945 , they attacked the British troops in Surabaya , killing two hundred soldiers . On 30 October the British flew Sukarno ( president of RI ) , Mohammad Hatta ( the vice president of RI ) , and Amir Syarifuddin Harahap ( the minister of information of Indonesia ) into Surabaya to possibly negotiate a cease fire . A cease fire was negotiated with Major General Hawthorn ( the commander of 23rd British Indian Division ) and Brigadier Mallaby and immediately adhered to . Fighting , however , soon recommenced due to confused communications and mistrust between the two sides , leading to the famed Battle of Surabaya . Death of Brigadier Mallaby . On 30 October 1945 , Brigadier A . W . S . Mallaby , the British brigade commander in Surabaya , was travelling about Surabaya to spread the news about the new agreement to his troops . When his car approached the British troops ' post in the International building near the " Jembatan Merah " ( " Red Bridge " ) , his car was surrounded by Indonesian Republican militia . Shortly after , Mallaby was shot and killed by the militia under confused circumstances . Captain R . C . Smith , who was in the stationary car , reported that a young Republican shot and killed Mallaby after a short conversation . Smith then reported throwing a grenade from the car in the direction of where he thought the shooter had hidden . Although he was not sure whether or not it hit its target , the explosion caused the back seat of the car to ignite . Other accounts , according to the same source , stated that it was the explosion and not a shooter that killed Mallaby . Regardless of its exact details , Mallaby ' s death was a significant turning point for the hostilities in Surabaya , and a catalyst for the battle to come . The British ordered an Indonesian surrender , and on 10 November they rolled out a large retaliatory attack . The main battle . Lieutenant General Sir Philip Christison was angered when he heard that Brigadier Mallaby had been killed in Surabaya . During a lull in the fighting , the British brought in reinforcements and evacuated the internees . An additional two brigades ( 9th and 123rd British Indian ) of the 5th British Indian Division led by Major General Robert Mansergh were deployed with Sherman and Stuart tanks , 2 cruisers and 3 destroyers ( including ) in support . At dawn on 10 November , a day now commemorated in Indonesia as Heroes ' Day , British troops began a methodical advance through the city under the cover of naval and air bombardment . Fighting was heavy , with British troops clearing buildings room by room and consolidating their gains . Despite the fanatical resistance of the Indonesians , half of the city was conquered in three days and the fighting over in three weeks ( November 29 ) . Estimates of Indonesian deaths range between 6 , 300 and 15 , 000 , and perhaps 200 , 000 fled the devastated city . British Indian casualties totalled approximately 600 . Aftermath . The Republicans lost much of their manpower , but it was the loss of weaponry that would severely hamper Republican military efforts for the remainder of the independence struggle . The battle for Surabaya was the bloodiest single engagement of the war , and demonstrated the determination of the rag - tag nationalist forces ; their sacrificial resistance became a symbol and rallying - cry for the revolution . It also made the British reluctant to be sucked into a war , considering how stretched their resources in southeast Asia were during the period after the Japanese surrender ; within a few years , in fact , Britain openly supported the Republican cause in the United Nations . It was also a watershed for the Dutch as it removed any doubt that the Republic was a well - organized resistance with popular support . In November 1946 , the last British troops left Indonesia . The " Heroes of the 10 November " statue in Surabaya commemorates this battle . 10 November is now commemorated in Indonesia as " Heroes ' Day " , in memory of the battle . References . Other sources