rest of the troops were able to land. Although 2nd Battalion, 15th Punjab Regiment, resisted the attack, they were soon outnumbered and retreated up the river. By the afternoon, Kuching was in Japanese hands. On the night of 23–24 December, HNLMS K XVI torpedoed the Japanese destroyer Sagiri north of Kuching, becoming the first Allied submarine in the Pacific to sink a warship. K XVI was lost with all hands during the day by a torpedo from Japanese submarine I66. On 24 and 28 December, B-10 bombers from a different unit flew missions against Kuching from Singapore, Sembawang. On 26 December, B-10s operating out of Samarinda sank a Japanese minesweeper and a collier. Meanwhile, on 31 December 1941, the force under Lieutenant Colonel Watanabe moved northward to occupy Brunei, Labuan Island, and Jesselton (now called Kota Kinabalu). On 18 January 1942, using small fishing boats, the Japanese landed at Sandakan, the seat of government of British North Borneo. The North Borneo Armed Constabulary, with only 650 men, hardly provided any resistance to slow down the Japanese invasion. On the morning of 19 January, Governor Charles Robert Smith surrendered British North Borneo and was interned with other staff. At about 16:40 on 25 December, Japanese troops successfully captured Kuching airfield. The Punjab regiment retreated through the jungle to the Singkawang area. After Singkawang was secured as well on 29 December, the rest of the British and Dutch troops retreated southward further into the jungle, trying to reach Sampit and Pangkalanbun, where a Dutch airfield at Kotawaringin was located. South and central Kalimantan were taken by the Japanese Navy following attacks from east and west. The town of Pontianak was finally occupied by the Imperial Japanese forces on 29 January 1942. After ten weeks in the jungle-covered mountains, Allied troops surrendered on 1 April 1942. References Runciman, S., The White Rajahs: A History of Sarawak from 1841 to 1946, particularly 252–5. Cambridge University Press, 1960. Percival, Arthur Ernest The War in Malaya, (especially Chapter XII: Operations in Borneo.) London, Eyre & Spottiswoode, 1949. L., Klemen, 1999–2000, The Netherlands East Indies 1941–42, " The Invasion of British Borneo in 1942". L., Klemen, 1999–2000, The Netherlands East Indies 1941–42, " The Japanese occupation of Sandakan, January 1942". Governors of North Borneo, World Statesmen. Citations Battle of Borneo (1941-42) Battle of Borneo (1941-42) Battle of Borneo (1941-42) Battle of Borneo (1941-42) Battle of Borneo (1941-42)