Sarawak remained part of the Empire of Japan for three years and eight months. Sarawak, together with North Borneo and Brunei, formed a single administrative unit named "Kita Boruneo" (Northern Borneo) under the Japanese 37th Army headquartered in Kuching. Sarawak was divided into three provinces, namely: Kuching-shu, Sibu-shu, and Miri-shu, each under their respective Japanese Provincial Governor. The Japanese retained pre-war administrative machinery and assigned Japanese for government positions. The administration of Sarawak's interior was left to the native police and village headmen, under Japanese supervision. Though the Malays were typically receptive toward the Japanese, other indigenous tribes such as the Iban, Kayan, Kenyah, Kelabit and Lun Bawang maintained a hostile attitude toward them because of policies such as compulsory labour, forced deliveries of foodstuffs, and confiscation of firearms. The Japanese did not resort to strong measures in clamping down on the Chinese population because the Chinese in the state were generally apolitical. However, a considerable number of Chinese moved from urban areas into the less accessible interior to lessen contact with the Japanese. Allied forces later formed the Z Special Unit to sabotage Japanese operations in Southeast Asia. Beginning in March 1945, Allied commanders were parachuted into Borneo jungles and established several bases in Sarawak under an operation codenamed "Semut". Hundreds of indigenous people were trained to launch offensives against the Japanese. During the battle of North Borneo, the Australian forces landed at Lutong-Miri area on 20 June 1945 and had penetrated as far as Marudi and Limbang before halting their operations in Sarawak. After the surrender of Japan, the Japanese surrendered to the Australian forces at Labuan on 10 September 1945. This was followed by the official surrender ceremony at Kuching aboard the Australian Corvette HMAS Kapunda on 11 September 1945. The Batu Lintang camp was liberated on the same day. Sarawak was immediately placed under British Military Administration until April 1946. After the war, the Brooke government did not have enough resources to rebuild Sarawak. Charles Vyner Brooke was also not willing to hand over his power to his heir apparent, Anthony Brooke (his nephew, the only son of Bertram Brooke) because of serious differences between them. Furthermore, Vyner Brooke's wife, Sylvia Brett, tried to defame Anthony Brooke in order to install her daughter to the throne.