The Battle of Ambarawa, or sometimes called Palagan Ambarawa, was a military conflict between the recently created Indonesian army and British troops that occurred between 20 October and 15 December 1945 on Ambarawa. On 20 October 1945 British troops that had landed in Semarang to disarm Japanese troops and liberate Europeans still detained in concentration camps in Indonesia were detached to Ambarawa. The Netherlands Indies Civil Administration was landed on Semarang, too. This is the problem that made the Indonesians mad and started the conflict with the Allied Forces.