The caves of Ehime Prefecture are arranged in a band from north-east to south-west. Hiroshi Yamauchi and Akihiko Kashima founded the 媛大学学術探検部 (Ehime University Exploration Department), which does the exploration. In 1972, they divided Ehime Prefecture into seven regions and reported 101 caves. In 1987-1988 Kashima introduced the ordering of caves in Ehime Prefecture by geological zone.