Japanese natural mineral water soak Or so called onion. It is a popular culture of Japan for over 1,000 years, which today many ryokan. In Japan, this method is used to call customers. The model of the hot springs to impress tourists. With nature is so close to the immersion to enjoy the forest, waterfalls as well as ancient. By simulating old architecture. Japanese style. Because the Japanese believe that the hot water soaked, it will make the blood circulation. The skin is fluffy.