Intro to Political Geography By ; Zach mazur
First I'm going to lay out some ground knowledge. According to the Merriam Webster Dictionary, a Nation is "a large area of land that is controlled by its own government", a State is " a politcally organized territory that is administered by a sovereign government abd us recognized by a significant portion of the international community. A state has a defined territory, a permanent population, a government, and is recognized by other states.", a Nation state is "a form of political organization under which a relatively homogeneous people inhabits a sovereign state; especially : a state containing one as opposed to several nationalities". These are the basics we will use.
According to wikipedia, "Japan: Japan is also traditionally seen as a good example of a nation-state, although Japan includes minorities of ethnically distinct Ryūkyū peoples, Koreans, Chinese, and on the northern island of Hokkaidō, the indigenous Ainu minority." This means that Japan meets the criteria to be a nation - state.