Digital technology affords new modes of engaging with gender, often in ways that challenge extant inequalities through simulation and transformation. Yet digital iterations of gender do not make a radical break with pre-existing lived experiences and practices and can even support the development of conservative or exclusionary gender ideologies rather than proliferation of difference. Furthermore, the major research activity around Japanese digital cultures to date has tended to cleave to disciplinary boundaries without a great degree of cross-reference, and so key approaches and definitions central to the study of digital technologies and cultures vary across different fields. This problem is exacerbated by the ubiquity of digital technologies in various aspects of Japanese life. This chapter brings together a diverse array of research on digital cultures in Japan in order to survey the fast-developing field and at the same time argue for drawing a wider definitional boundary around that field. The chapter concludes with a case study of later-life smartphone use and its gendered implications.