An onsen that bubbles up in Tomonoura, a historic port town with a long history dating back to ancient times, located almost in the center of the Seto Inland Sea. This area is associated with Sakamoto Ryoma and is said to have been a model for the setting of Studio Ghibli's film Ponyo on the Cliff by the Sea. The nostalgic scenery of this old-fashioned port town remains intact. The beautiful landscape, which feels like stepping into the world of Ghibli, combined with high-quality hot spring water boasting one of the highest radium contents in Japan, makes it immensely popular with foreign visitors who long for Japan's traditional original landscapes.