Taiwanese business people and tourists. Japanese spies, which included a British intelligence officer, Captain Patrick Stanley Vaughan Heenan and Lord Sempill also provided intelligence and assistance. Heenan's intelligence enabled the Japanese to destroy much of the Allied air forces on the ground. Prior to hostilities, Japanese intelligence officers like Iwaichi Fujiwara had established covert intelligence offices (or Kikans) that linked up with the Malay and Indian pro-independence organisations such as Kesatuan Melayu Muda in Malaya and the Indian Independence League. The Japanese gave these movements financial support in return for their members providing intelligence and later assistance in determining Allied troop movements, strengths, and dispositions prior to the invasion. By 1941 the Japanese had been engaged for four years in trying to subjugate China. They were heavily reliant on imported materials for their military forces, particularly oil from the United States. From 1940 to 1941, the United States, the United Kingdom, and the Netherlands imposed embargoes on supplying oil and war materials to Japan. The object of the embargoes was to assist the Chinese and encourage the Japanese to halt military action in China. The Japanese considered that pulling out of China would result in a loss of face and decided instead to take military action against US, British and Dutch territories in South East Asia. The Japanese forces for the invasion were assembled in 1941 on Hainan Island and in French Indochina. The troop build-up in Indo-China and Hainan was noticed by the Allies and, when asked, the Japanese advised that it related to its operations in China. Conquest The occupation commenced with Imperial Japanese Army landings at Padang Pak Amat beach Kota Bharu just after midnight on 8 December 1941, triggering a ferocious battle with the British Indian Army an hour before the attack on Pearl Harbor. This battle marked the official start of the Pacific War and the start of the Japanese occupation of Malaya. Kota Bharu airport was occupied in the morning. Sungai Patani, Butterworth, and Alor Star airports were captured on 9 December 1941. Japanese soldiers landing at Kota Bharu divided into two separate forces, with one moving down the east coast towards Kuantan, and the other southwards towards the Perak River. On 11 December 1941, the Japanese started bombing Penang. Jitra and then Alor Star fell into Japanese hands on 12 December 1941. The British had to retreat to the south. On 16 December