We describe the largest group of cave sites in Japan known to date. It includes some 50 sites, located in a gorge within the area of the modern Taishaku National Natural Park. Their characteristics are provided and their relevance to the study of the early stages of the Jomon Period is assessed. The study is based on publications, fi eld reports, and samples of artifacts owned by the museums in the Hiroshima Prefecture. The focus is on cave sites in the Chugoku region, their location, structure, inner space, and utility zones in the adjoining territory. Special attention is paid to the reconstruction of sequence in which parts of the cave space were exploited at different stages of the Jomon Period. Archaeological fi nds are described in detail—stone and bone tools, potsherds, and mollusk shells. Their analysis suggests that the Jomon people who lived in those caves subsisted mostly by hunting and freshwater mollusk collecting. Shells of marine mollusks and tools made of sanukite, which is unavailable in the area, indicate trade relations between cave dwellers and people of the adjoining regions, including the sea coast. A conclusion is made that population growth and greater reliance on hunting and fi shing territories rich in vegetation led to the change in lifestyle and subsistence strategies of the Jomon people.