Sino-Japanese relations are one of the most conspicuous bilateral relations in the International Relations discipline, affecting regional and global politics. Despite two different wars and painful memories, both countries have managed to sustain mutual relations today. China and Japan reached one of the world’s highest volumes of bilateral economic relations. Nevertheless, the international affairs of both countries are still struggling with certain issues. As long as the countries understand each other’s red lines, they can keep communication channels open. Chinese diaspora today is spread out in many different corners of the world. One of the most substantial Chinese diasporas has been located in several cities in Japan for more than two hundred years. Chinese immigrants mainly seek better living standards and higher incomes than their homelands. However, their transnational ties, diasporic solidarity, and hardworking features help the mutual understanding of both societies and governments. Chinese workers in Japan perform almost all stages, including academia to manual workers, medicine to robotics, and law to car industries. Therefore, Japanese people in almost all sectors may witness a Chinese character, work ethic, and know-how. Chinese international students, on the other hand, are experiencing Japan with different roles: a student, a part-time worker, a scholarship applicant, a jobseeker, etc. Potential skilled or highly skilled workers who know the Japanese language, culture, and know-how in a specific field are increasing. Hence, this paper focuses on Sino-Japanese relations from the point of international migration. Initially, the historical context of bilateral relations will be given, and then the features of the Chinese diasporas will be investigated. Later, Chinese immigration to Japan will be explored. Finally, international students in Japan from China will be uncovered, as a new phenomenon of international migration and international politics.