This paper will discuss 'An Introductory to Hokkien' (『福建語入門』) , a textbook of Hokkien language written by Ichinari Otoshige during the Asia-Pacific War. He had taught Taiwanese, the same language as Hokkien, to the Japanese in Taiwan during the early Japanese colonial period. He, however, called the language Hokkien, not Taiwanese, in the textbook's title in 1942 because he wanted to describe it, not as the Taiwanese language but as the language of the overseas Chinese living in the "Southern Co-Prosperity Sphere." The people and the sphere, however, were not portrayed in the textbook for the Japanese learners, albeit some names of the places and movements of the Japanese and Taiwanese in the sphere were used as topics in the dialogues. It is fair to say that cultural translation, which authors of second language textbooks are usually required to achieve, cannot be found in 'An Introductory to Hokkien,' unlike the Taiwanese textbook he wrote in 1904 in which he seemed eager to translate the Taiwanese society and people to its Japanese readers.