“Tengu-no-mugimeshi” is a microbial aggregate unique to the Asama-Eboshi volcanic region, historically referred to as “edible soil” due to its consumption by people. The variety found in Komoro City has been designated as a Natural Monument by the Japanese government. From the Meiji to Showa periods, Japanese botanists and zoologists demonstrated keen interest in “Tengu-no-mugimeshi,” resulting in several research papers, essays, and reports that remain to this day. In recent years, molecular biological techniques have been employed to analyze microbial communities and isolate key bacterial groups, gradually revealing the nature of “Tengu-no-mugimeshi.” However, its ecology and formation processes remain largely a mystery. This study comprehensively reviews previous biological and geological research on “Tengu-no-mugimeshi,” examining its ecology and formation while discussing its significance as both a cultural heritage and a valuable microbial resource.