The historical, vernacular, residential forms and processes of urban Japan are to be explored as a potential source of power with regards to the concept of developmental vernacular architecture. This theory is a relatively new and vaguely defined approach to a combined method of conservation and progressive growth; balanced elements of a "smart growth" strategy. Therefore, a clarification of the term, along with an initial analysis of the definitions and values of vernacular architectures, is needed. Secondly, The Japanese machiya type will be explored as a unique vernacular form, indicating its diversity over time and similarity over distance. The essential controls and stimulus of its formal evolution and common characteristics will be examined. Machiya, a Japanese term, translates roughly to townhouse, in English. It is typically a city dwelling which also includes a small shop or metting space that fronts the street. This is the typical dwelling of the urban merchant class. The long of history of its development and its many transformations will be discussed. These analyses ultimately lead to the design exercise which investigates the machiya type as an intelligent base for a developmental vernacular process within the context of the Japanese urban environment. Therefore, the conclusion is to present, or to infer, the merits of incorporating such a program into a wider extent of the current built environment; poor and affluent, urban and rural. / Master of Architecture