The Gifu Prefecture is located in the center of the mainland Japan, an area which is also called the Japanese Alps. The area is formed by steep mountains with many hot springs, the base of a favourite Japanese pastime: onsen (hot bath). Many limestone patches in the complex and mostly volcanism based geology are the location of karst caves.
One of these places is the famous town Gujo Hachiman. In Japan it is famous for being the place wher plastic food replicas were invented, the ones which are on display at every Japanese restaurant to give an impression what food is sold. They are still produced at the town. More interesting for us is the karst area in the mountains to the south, where over 500 karst caves are known. Three are open to the public, Otaki Shonyudo, Jomon Shonyudo, and Miyama Shonyudo.