Abstract
The term sound material-cycle society (SMCS) is intended to integrate environmentally sound management of solid wastes and efficient use of material resources, and it is sometimes expected to imply long-term vision of a society toward sustainable development. Japanese practices for SMCS have had good progress in general, whereas obstacles such as conflicts in cost sharing among stakeholders and influences of increasing resource demands by neighbourhood developing economies are revealed. Research perspective to fill the gap between the concept and the practice of SMCS is discussed. Relation between material flows and material stocks is essentital in the field of civil engineering.