According to local legend, people have been visiting Zao since 110 CE. The hot springs are believed to have been discovered by soldiers who were sent to find cherry blossoms. A local ruler was shot with a poisoned arrow, and as he lay dying, he asked his retainers to bring him a sprig of cherry blossoms so that he could see their beauty one last time. His retainers went into the nearby hills and mountains to search for a cherry tree. Cresting a ridge, one of the retainers was caught off guard by what looked like smoke from the cookfire of an enemy camp. He went to investigate and discovered not a fire but a hot spring with bubbling waters. The retainer brought his lord to the pool and watched in wonder as his master was healed upon entering the water. So goes the story, but whether the life-saving properties of the water are true or not, there is no doubt that Kamiyu public bath is the spring it describes, the source of the hot spring water in Zao.