ABSTRACT
Legal sex, the classification of a person as either male or female, in Japan is mediated through familial relationships documented on the family register (koseki). This institutionalizes marriage and family and places familial identity, gender identity, and gender role at the centre of a person’s legal identity, the effect of which is felt in the broader context of Japanese society and everyday lives in complex and diverse ways. This, combined with a patriarchal, moralistic, and heteronormative approach to defining the legal family, means notions of gender/sex are moulded within the family registration system (koseki seido). There is much to gain in researching the koseki for scholars of gender in Japan and gender studies in general. This chapter provides an introduction to the field with commentary of the field and its future
