The author attempts to analyze several categories of the Japanese political culture of the Nara period of the 7th–8th centuries AD, such as harmony (wa 和), and righteousness (gi 義). The author supposes that the existential disposition of trust forms the basis for such categories. In Confucian tradition, this disposition is expressed through trustworthiness (sin 信). The article begins with an overview of the Japanese political culture of the Nara period in order to clarify the place of wa, gi, and sin in Japanese political thought. The author pays close attention to the roles of language and myth in Japanese culture as well. It is argued that political culture is a sort of superstructure for language, which is a substructure. Since language is the logos of culture as a whole, it is possible to identify the existential meanings of categories of political culture that are ontologically rooted in language. The author claims that the patterns of political thinking in Japanese tradition are reflected in myth. In order to prove this, the authors offers an analysis of the use of such characters as wa 和 and gi 義 in the Japanese chronicles Kojiki and Nihongi, highlighting the variety of their meanings and the close connection with trustworthiness as their basis.