At the end of World War II many Indonesians believed that independence was imminent. Few realized that it would be another five years of fighting before the country became a fully independent republic. The area around the east Javanese town of Surabaya became the scene of some of the heaviest fighting, and the Battle of Surabaya, which cost the lives of many thousands of Indonesians, became a symbol of resistance to the re-imposition of Dutch colonial rule.
Late October 1945, some 6,000 British troops of the 49th Brigade of the 23rd Indian Division under Brigadier Mallaby, entered Surabaya with orders to organize the recovery of Allied POW. However, the British also sought to establish complete control of Surabaya, but had underestimated the extent of Indonesian resistance and the numbers they faced. They found themselves up against a force of 20,000 troops of the newly-formed and Japanese trained People's Security Army (Tentara Keamanan Rakyat), and over 100,000 irregular fighters, all dedicated to the cause of Indonesian independence. Fierce fighting broke out on 28 October, and soon the Indonesians had surrounded the British command posts scattered throughout the city. A truce was reached on 30 October, but as evacuations to the harbour area was arranged, in the excitement and confusion, more fighting erupted during which Brigadier Mallaby was killed. The British then decided to take Surabaya by force, and secretly landed 24,000 troops of the battle-hardened 5th Indian Division, with Sherman medium tanks, backed by naval and air support.
On 9 November, the British gave the Indonesians an ultimatum, ordering their leaders to surrender. When they refused, Surabaya was mercilessly bombarded on 10 November, heralding a battle that was to last three weeks, at the end of which 200,000 of the town's population had fled, mainly the elderly, women and children. Over 16,000 Indonesian troops were killed and 2,000 British soldiers lost their lives.
The Battle of Surabaya was the heaviest single battle of the revolution and became a national symbol of Indonesian resistance. In Indonesia, 10 November is celebrated annually as Heroes Day.