1941, the British left Penang to the Japanese, who occupied it on 19 December. The Japanese continued to advance southwards, capturing Ipoh on 26 December. Fierce resistance to Japanese progress in the Battle of Kampar lasted three days and three nights between 30 December 1941 and 2 January 1942, before the British had to retreat once again. On 7 January 1942, two brigades of the 11th Indian Infantry Division were defeated in the Battle of Slim River, giving the Japanese army easy passage to Kuala Lumpur, the capital of Malaya. On 9 January, the British position was becoming more desperate and the ABDACOM Supreme Commander, General Wavell, decided to withdraw all the British and Commonwealth forces south to Johor, thus abandoning Kuala Lumpur (which was captured by the Japanese on 13 January). The British defensive line was established in north Johor, from Muar in the west, through Segamat, and then to Mersing in the east. The 45th Indian Infantry Brigade were placed along the western part of the line between Muar and Segamat. The Australian Imperial Force (AIF) were concentrated in the middle, from where they advanced north from Segamat, clashing with the advancing Japanese army at Gemas on 14 January. The 15th Division (forming the main Japanese force) arrived on 15 January and forced the Australians back to Segamat. The Japanese then proceeded west towards the inexperienced 45th Indian Brigade, easily defeating them. The Allied command directed the Australian 2/19th and 2/29th Battalions to the west; the 2/19th Battalion engaged the Japanese on 17 January 1942 to the south of Muar. Fighting continued until 18 January, and despite efforts by the 2/19th and 2/29th Battalions, the Johor defensive line collapsed. The Allies had to retreat across the Johor Causeway to Singapore. As 31 January 1942 approached, the whole of Malaya had fallen into Japanese hands. Occupation Japanese policy Japanese policy for the administration of occupied territories was developed in February 1941 by Colonel Obata Nobuyoshi (Section Chief of Intelligence – Southern Army), and Lt Colonels Otoji Nishimura and Seijiro Tofuku of the General Staff. They set out five principles: acquisition of vital materials for national defence, restoration of law and order, self-sufficiency for the troops in the occupied territories, respect for established local organisations and customs, and no hasty discussion of future status of sovereignty. Administrative-wise, the Straits Settlements were to be placed directly under the Japanese Army, the