Objective  China has entered a phase of rapid and extensive urban stock renewal. While the Ministry of Housing and Urban-Rural Development of the People’s Republic of China and other government departments propose that urban renewal should avoid large-scale demolition and construction in response to current progress, and they also propose that the scale and quality of urban public space should be actively increased, reflecting the ongoing pursuit of urban livability. However, the practice of increasing the scale of public space has revealed that there are fewer spatial resources available in built-up areas of cities, particularly in central areas, and new types of public spaces need to be actively developed. Among these, the leftover spaces are considered to be public spaces with special potential. While they have the advantages of being numerous, widely distributed and more closely linked to settlements, they are also often small in scale, mixed in status and low in effectiveness. In response to such complex characteristics, micro-renewal models are mostly used for optimization around the world. In practice, it has been found that due to the inadequacy of the planning system, the micro-renewal of leftover spaces still generally face the problem of coupling the physical and social aspects of space, especially the social benefit dimension. This is mainly due to the fact that there is still a lack of knowledge about the ontological characteristics of leftover spaces and the renewal thereof, which makes it difficult to balance multiple objectives at the practical level. This research analyzes the nature of the problem of urban leftover space from the perspective of social design, arguing that its social reflection on the purpose, subject, product and process of design can enhance the theoretical understanding and practical effect of the micro-renewal of leftover spaces. The concept of social design originated from Moholy Nagy’s initiative to establish a “parliament of social design” under the Bauhaus system in the 1940s, which actually emphasizes the front end of design practice, namely the correction of the value of design concept, indicating that design should have social attributes and should embrace social values and responsibilities. From this perspective, the design of public spaces and the renewal of leftover spaces are undoubtedly a social design practice, which should follow the concepts of social design.

Methods/Process  Starting from the essential interpretation of design with social design as an example, this research emphasizes the public properties of public spaces and leftover spaces, the design objects, focuses on social connotations, analyzes social network problems, and proposes social design solutions, thus contributing to the close integration of physical space design and social action. From the disciplinary perspective of social design, this research combines theoretical research and practical cases at home and abroad to reflect on both epistemology and methodology: at the epistemological level, the micro-renewal of leftover spaces requires designers to think about “whom to design for”, “whom to design with” and “whom to design by”, and understand the value orientation, practice model and their respective roles in the aforesaid process; at the methodological level, designers need to balance specific practice and overall strategies to explore the transformation of micro-renewal of leftover spaces from spatial design to social design. Only by integrating knowledge and practice can social innovation and spatial intervention be carried out faster and better.

Results/Conclusion  From a social design perspective, this research finds that the essence of the urban leftover space problem lies in the non-collaboration of social networks and the need to rely on the power of social innovation for targeted social network repair. The analysis of literature allows for three conceptual reflections at the epistemological level: 1) design for the people, which means designers should focus on the value orientation of designing for the public welfare; 2) design with the people, which means designers should promote the improvement of the practice model of designing with multiple participants; 3) design by the people, which means designers should grasp their role as a medium to assist in the execution of design. These reflections require designers to pay further attention to the constitution of public stakeholders of leftover spaces, and the way(s) to divide the discourse power and to realize different interests. Based on case study, the research proposes four action suggestions at the methodological level. The micro-renewal of leftover spaces requires: 1) a focused vision, focusing on the real and concrete daily life; 2) a grasp of the direction, with “proximity” as the yardstick for spatial design; 3) a strong platform, with multiple participation to balance spatial interests; 4) institutional safeguards to synchronize spatial design with social mechanism innovation. Based on the above epistemological and methodological exploration, the research can help guide the transformation from traditional spatial design to social design, push designers to pay more attention to the practical, innovative and social aspects of spatial ontology and design process, introduce new concepts, new dynamics and new means, and ultimately promote the innovation of platforms and systems, thus truly combining spatial renewal with social design.