Come and experience Utase Yu bathing (an invigorating water massage) that is rare even for onsens in the Chugoku region, as it uses fresh and cool spring water (approximately 23.5°C) that is dropped from a height onto the bathers below.
The Hiroshima region has many of the so-called simple, weak-radioactive type hot springs with water that include radons, which are believed to have healing properties. The radons start to disperse when they come into contact with air and as this process is greatly accelerated by heat, ideally you should bathe in non-heated radon water. So the Utase Yu at the Yunoyama Onsen Resort is said to be the best way of bathing for simple, weak-radioactive type hot springs. In addition alternating between the cold bath and the heated indoor bath is an effective way of rejuvenating a tired body and mind.
Moreover, when you consider that the Yunoyama Onsen Resort is also an important historical site as it was used for bathing by the Asono family during the Edo period, then it becomes clear why it is considered one of the premier onsen (hot spring) resorts in Hiroshima.