Designing an effective platform in regional development, and specific design methods, were investigated. Action research was partially incorporated to create a practical wisdom. One problem in regional development is how to bring about social emergence once new links between people and organizations have been constructed. This is a comparative case study of the widely-expanding Hosujuku invoking theoretical research to consider the factors behind the successive emergence of new businesses. The results show that in platforms effecting social emergence, diverse actors pool their own resources and care is taken to have them be able to use those resources freely.