Ōkubo Kōji's works on Turkic languages

The aim of this study is to reveal Ōkubo Kōji's views on Turkish language and Turkish and his perception of Turkish concepts used in his works and the way he reflects this perception. For this purpose, Ōkubo Kōji's writings on Turkish language, Turkish and Turkish of Türkiye constituted the research sample of the thesis. As a result of the analysis, it has been determined that Ōkubo Kōji draws attention to the two basic features of Turkic languages as being an agglutinative language and having vowel harmony, and explains that Turkic language has not undergone major changes due to its solid structure and its rules like mathematics in its historical development. In his evaluations on the Turkic languages, which he states that there is not much difference between. It is seen that he evaluates Kazan-Tatar Turkish as an important cultural and written language, Kashgar Turkish as the easternmost dialect that has preserved its classical form the most, and Turkish of Türkiye as the most developed Western dialect. In the thesis, it was also determined that he followed the language policies in Türkiye, formed opinions about them and conveyed these issues to Japan through his publications. It has been observed that he evaluated the alphabet revolution and the language revolution in Turkish as a need that meets the structural needs of Turkish, and the the Sun-Language Theory as an ideological initiative based on a nationalist plan. It was also concluded that Ōkubo approached Turkish culture through language in order to recognize and introduce the Turkish people. As a result, it is seen that Ōkubo Kōji, who tried to recognize and introduce the Turkic peoples living in a wide geography, wrote many works as a Turkic studies researcher as well as being a researcher in Islamic history and civilization.