In Japan, over 4000 historic buildings are designated as Important Cultural Properties (ICP). Such designated buildings are generally regarded as important resources in the study of Japanese culture; however,they only tell part of the story when it comes to Japan’s religious and regional history. Many historic buildings with the potential to be important historical materials still remain uninvestigated, and for this reason I have been investigating non-designated historic buildings in the Hyogo and Shiga prefectures. In the course of my work I have encountered a large number of Buddhist temples and Shinto shrines with previously unknown regional characteristics. Through their studies, my colleagues and I have clarified the process of change in religious power from the medieval period to early modern times, revealed that certain buildings were utilized by multiple religions, and made other important discoveries. Through our work, rather than seeking to expand Japan’s roster of World Heritage Sites, we are seeking to elucidate diverse regional histories.