After Japan's annexation of Ryukyu in 1879, unprecedented Japanese influences have permeated into and spread throughout Okinawan society through public administrations, education, media, and other ways, leading to constructing Japanese identity among Okinawans. Of these modes of Japanization, I focus on education, which is centralized by the Japanese government. I share my research previously done regarding identity construction in educational settings in Okinawa. The unit of analysis includes a book excerpt in textbooks used in high schools in contemporary Okinawa. The analysis unveiled how Japanese identity can possibly be constructed among Okinawans through learning the content of this excerpt, or nihonjinron discourse, which is characterized by "Japanese culture," "Japanese uniqueness," and "Japaneseness." Nihonjinron discourse approved as a teaching material in textbooks by the authority of the Ministry of Education, Culture, Sports, Science and Technology functions as official knowledge, which students have to learn. This nihonjinron discourse illustrates the "East-West" dichotomy within which students can be induced to choose "Japan"/ "Japanese culture," internalize that culture, and become "Japanese." I problematize this nihonjinron discourse adopted in authorized textbooks as a systematic form of Japanizing Okinawans' minds through education. If this Japanization of Okinawans minds can be a legacy of or on-going colonialism, I argue that it is crucial to create an education program for Okinawan identity development to correct inequality and injustice in terms of ethnic identification in educational settings that have been under control of the centralized Japanese educational system.