Every year around the winter solstice, all the onsens in Kinosaki float several citrus fruits called yuzu in their baths. The yuzu fill the bath areas with light aromatic citrus scent. Bathing in the waters with these fruits is believed to ward away any colds for the coming winter.
Citrus Onsen this year will be held all day on (Wednesday) December 21 2016 at five of the seven bathhouses. (*Ichino-yu and Mandara-yu are reguarly closed on Wednesday)