The strategy and tactics of Japan's contemporary migration policy are determined by the ethnocultural characteristics of the Japanese nation, recognized as the concept of national character (国民性 kokuminsei), which is both a political and scientific entity. The rapid changes in migration policy today expose the practical need to study the causes, consequences, and specifics of related social and political concepts such as national character and the factors that shape it. The accurate knowledge helps predict cultural, political, and socioeconomic changes and future agendas. This concept is a subject of paramount importance for international relations studies, as it is rooted in the Japanese nation's self-consciousness and represents core elements of national history within its interrelation with present policy. The study suggests that the Japanese national character, described and conceptualized in the late Edo period (1603–1868) and the Meiji period (1868–1912), still influences the attitudes of the Japanese towards migration and foreigners in general. The representatives of kokugaku (国学 national study) that originated at that time and nihonjin-ron (日本人論 theories about the Japanese) that developed further sought to assert the authenticity of Japanese culture and its history and construct a national identity. Assumingly, it would become an instrument of protecting the country from the influence of China and later the West. Today, researchers of Japanese culture, both in Japan and abroad, continue to refer to post-war nihonjin-ron, criticizing, rethinking, or adding to its major provisions. Content analysis of the vocabulary used in connection with the concept of national character in official documents regulating the relevant area of social policy, as well as in the media and social networks, has revealed some features of the modern interpretation of this concept. In particular, there are attempts to identify socially significant features of a member of Japanese society. Certain acculturation efforts required from migrants imply the development of the skills that are socially important from the point of view of Japanese society. The comprehensive analysis of measures for the integration and adaptation of migrants implemented by the local governments of Japan has shown that communicative phenomena associated with the concepts of meiwaku (迷惑 causing trouble), omoiyari (思いやり considerate caring for others), as well as the culture of gift-giving and apologizing play an important role in the relationships between Japanese and foreigners. In addition, the analysis of migration policy allows concluding that the concept of coexistence between Japanese and foreigners (多文化共生 tabunka kyousei) currently pursued by the government, despite its promising title, does not quite correspond to multiculturalism in its classical sense, in other words — does not imply deliberate government action to preserve and develop cultural differences within one society.