While the medium-of-instruction (MOI) has been seen as one of the most crucial decision-making areas in language policies, it is curious that the equivalent Japanese expression to MOI is absent from educational policy documents. In a nation where the Japanese language is called the national language and enjoys the status of an official language, the absence of the MOI in policy documents is closely related to the fact that the so-called English education in Japan has been removed from bilingual education. In the new millennium, the Japanese government has continuously sought to increase the profile of English in two ways: by improving the overall English proficiency of Japanese students, and by attracting overseas students to Japanese universities in the name of internationalisation. The new senior-high-school English curriculum that aims to "conduct English classes in English" was fully implemented in 2013, and the so-called Global 30 Project is expected to attract some 300,000 overseas students by 2020 to "English-only" degree programmes established at core universities. This article argues that rather than equating with the MOI, the "English-only" initiative can be seen as a tactic for facilitating the co-existence of the national language and English without formalising the status of English as a MOI. By examining government education policies and relevant documents using critical discourse analysis, it also argues that Japan's dualism (Japanese and the Other) or the mechanism of Othering is behind these initiatives. (Contains 1 table and 29 notes.)