This dissertation examines the history of menstruation leave ( seiri kyuka ) in modern Japan. Menstruation leave, as articulated in Article 67 of the Japanese Labor Standards Law of 1947, gave menstruating women the right to absent themselves from work if they were experiencing difficulties working or were engaged in types of labor activity considered hazardous to the menstrual cycle. This project traces and seeks to understand the social-cultural formation in Japan of a gendered workers' right that is strikingly uncommon in both industrialized and industrializing countries. This study argues that a confluence of factors and developments involving working women, scientific studies of labor, and state mechanisms allowed for the formation of menstruation leave in Japan. Menstruation served as an important lens through which the state and scientists analyzed their subjects, and its absence and disorders were interpreted as the malignant results of the industrial capitalist system. The bodies of working women embodied the increasing conflict between wage and reproductive labors, and the debates surrounding menstruation leave provide insight into how the physiological phenomenon was interpreted and represented by competing social interests.

This dissertation discusses how menstruation was viewed in Japan prior to the twentieth century; the normalizing discussions on menstruation through state mechanisms, the academic field of "school hygiene" and women's hygiene magazines from the late nineteenth century to the mid-twentieth century; the role of the Institute for Science of Labor in interpreting the relationship between female wage laborers and their reproductive functions; labor disputes and menstruation leave in the early twentieth century; the shift of private research into governmental studies and policies through the Industrial Patriotic Labor Association (Sanpo) in the early 1940s; and the trans-war continuities in the debates over menstruation leave during the creation of the Labor Standards Law and after menstruation leave's enactment.