This study explores the transformation of toilet spaces in Japan from 1910 to 1954, focusing on the efforts of the Japanese Ministry of Health, Family Welfare, home economics scholars, and housing improvement associations to enhance sanitation. By examining the toilet as a symbol within residential spaces, this research redefines it as an ‘in-between space’ created by the intersection of dominant residential spaces and the outside world. The study investigates how toilets were glorified and positioned at the forefront of sanitation administration from a translocality perspective. Through text mining analysis, key terms such as ‘cubic feet’, ‘necessity’, ‘filter material’, and ‘quantity’ were identified, reflecting the primary concerns related to toilets at the time. This study reveals that toilets, once seen as symbols of bad smell and uncleanness, were transformed into spaces essential for the virtuous cycle of waste management and hygiene. The modernization of toilets, particularly with the introduction of flush toilets and sanitary facilities, had a profound impact on public health, social norms, and cultural practices in Japan. The research also highlights the role of toilets in enhancing family bonds and social connectivity, driven by government policies and media campaigns. The integration of toilets into residential spaces represents not just a practical improvement but a cultural innovation, reflecting Japan’s modernization and westernization trends. The findings underscore the importance of toilets as boundary spaces that embody both physical and conceptual transitions within Japanese society, contributing to a deeper understanding of the spatial order of exclusion and inclusion.