To ensure sustainable development in health care systems and to bringabout workable ideas wich are widely accepted, there must be dialogue and collaboration between highly diverse stakeholder groups, such as medical practi-patients and their families. However, diversity between these actors requires methodologies that enable the participants working on change and development processes together. It is important to understand each other's work situations, demands and constraints to collaborate on future ideas. Therefore, we suggest a so-called serious play methodology wich combines tool-kit based modelling using LEGO® building blocks and story-telling to foster the development of shared understandings between different stakeholders. In an empirical example of a system development process between health care practitioners in Japan, we describe and discuss apllocation of this methodology