Also known as "golden hot water" because of its brownish-brown color that changes when exposed to air, it contains one of the highest levels of hydrogen carbonate in Japan. It is popular among islanders and visitors to Rishiri Island as "hot water for beautiful skin" and "refreshing hot water" because it leaves the skin smooth after bathing. There are also two types of saunas: hot and cold. The water is heated to maintain the proper temperature, and is both free-flowing from the source and circulated and filtered to maintain efficacy, hot spring resources, and sanitary management. The open-air baths with a view of the sun setting over the Sea of Japan and the sky full of stars are also popular.