Previous studies have suggested that there were two or three types of headship succession practices in Tokugawa Japan. The Tokugawa Period (= Japanese early modern period) is the first period for which the family life and inheritance customs of individual common people can be examined through a written record. Some historical-demographic and historical family studies have found that Tokugawa society exhibited diverse family norms and practices. Two types of family practices were emphasised in particular: The northeastern pattern is characterized by primogeniture and the vertically extended nature of households, in contrast to the pattern in the central and southwestern regions, where nuclear households were prevalent in higher proportions. The third type of family structure was observed in village studies of western and southwestern Japan. In this study the author will attempt not only to describe further evidence of family structure diversity in western Japan, but also to examine the concept of regional diversity. The determinants of inheritance patterns in Tokugawa Japan will be examined by a local study of Yukinobu, a village of Western Japan, now in Okayama, Chugoku Region.