This article examines one characteristic feature of Japanese bureaucracy in ancient times : shitokan 四等官, the ranked hierarchy of kami 長官(chief), suke 次官(deputy chief), jo 判官(office manager) and sakan 主典(clerk) that operated each bureau. The discussion is based on the ritsuryo code revisions of the early ninth century and documents pertaining to the eighth century. The day-to-day administrative affairs of the ritsuryo government's eight bureaus during the eighth and ninth centuries were conducted mainly by the lower three officials, with the bureau chief kami seldom participating. Most decisions were made by the deputy chief suke, but in important matters of government the kami would replace suke as decision maker, and in even more important matters conducted in the central government office, a minister of state would take over. In this administrative structure, the core unit of suke, jo, and sakan carried out their administrative duties either by themselves or by interacting with the kami or minister, depending on the importance of a given issue. This practice was based on the principle established in the seventh century that each bureaucrat of the fifth rank was to be put in charge of a group consisting of two types of administrators : matsurigotohito and fubito. On the other hand, a large difference existed between jo and sakan with respect to job responsibility. Jo were given a degree of decision-making authority, and in relatively minor tasks they directed sakan in making decisions. Furthermore, regarding the appointment of jo, most were the sons or grandsons of bureaucrats of fifth rank or higher, while offspring of bureaucrats of sixthrank or lower and non-bureaucrats never made it past the position of sakan. In other words, Japan's ritsuryo government was structured in such a way that sons of bureaucrats of sixth-rank or lower and sons of non-bureaucrats had difficulty obtaining decision-making authority. The eight bureaus were administered by fifth-ranked bureaucrats, and the kami class supervised the bureaus from above. Kami were imperially appointed officials, which gave them a much higher status than bureaucrats of suke and below. With their direct links to the emperor, the kami in turn linked the emperor to the bureaus that were managed by fifth-ranked bureaucrats. This administrative system dates back to the seventh century as well. In these ways, the four-ranks bureaucratic hierarchy of Japan's ritsuryo government may bear a surface resemblance to the Tang system, but its inner working were completely different; namely, it was fundamentally limited by kinship relations and rules of family descent that predated the ritsuryo government.