The Mukden Incident in 1931 led to Japan’s invasion of China and the implementation of Japan’s Southern Advance Policy. The goal to establish the Greater East Asia Co-Prosperity Sphere was gradually strengthened and solidified. In order to coordinate the resources available in Taiwan, the Taiwan Sōtokufu (the Government-General of Formosa) set up the Provisional Commission for Economy, Trade and Industry in 1930 and the Research Committee for Tropical Industries in 1935. In the following year, the Taiwan Development Co., Ltd. was established. These establishments set out the structural changes of the industries in Taiwan and unveiled the South China and South Seas policy. Taiwan became Japan’s entry hall to the Southeast Asia and a base of providing military supports. Tracing the history of this particular period of time, the authors analysed the dossiers of the Taiwan Development Co., Ltd. to examine Japan’s foreign policies and the development of the industries in Taiwan. The authors have obtained new insights and fruitful results. Kouzui Otani was not only the High Priest of the Hongan-ji School of Jodo Shinshu Sect, but also the brother-in-law of the Emperor Taisho. He travelled through Central Asia as an adventurer, and formed a close relationship with China while preaching there. Moreover, Otani was a pioneer of the tropical industries in Southeast Asia. He showed interest in the tropical industries in Taiwan in 1930. His life reflected the changes in Asia and the expansion of the Empire of Japan from the late 19th century to the mid-20th century. Kouzui Otani was highly respected in Japan for his devotion to religion. Therefore, most discussions about him are mainly in the context of religion and may possibly be extended to his relationship with Taiwan. In fact, Otani’s relationship with Taiwan was tightly forged due to the development of the tropical industries and the use of resources in Taiwan to support Japan’s advance on the Southeast Asia. Through investigating the movement of Kouzui Otani in Asia, this study intends to find out the impact of Japan’s imperialism on people’s movement, as well as to examine the history of Taiwan after 1937 from the perspective of a Japanese.