Introduction to a special issue of the peer-reviewed journal Review of Japanese Culture and Society. The introduction, which draws on the expertise and knowledge of the three co-authors in modern art history (Adriasola), social history of design (Teasley) and spatial design studies (Traganou), sets out research questions, challenges and opportunities for studying the relationship between design and society in Japan, 1900-2015, looking both historically and at contemporary practice. The introduction intends to introduce current concepts of design as social practice to historians and other arts, humanities and social science scholars of Japan, and to demonstrate how a perspective that sees social spaces and networks as 'designed', and that views design and architecture practice and products as valid, valuable examples of historical conditions, can enable humanities scholars to engage more effectively with research into modern and contemporary Japanese culture and society. The introduction also offers an overview of key historical developments and conditions for design as an industry, profession and product in Japan, c. 1900-present day. It ends by challenging scholars who engage with design in Japan to address questions around gender, class and other determinants of power relations, and to understand design as an expanded practice, beyond the outdated, inaccurate and limiting view of design that persists within Japanese studies.