Shobuyu (bathwater with iris petals) (菖蒲湯)

Shobuyu is the bathwater heated with iris roots and leaves in it on Tango no Sekku (Boys' Day) of May 5. It is believed that by taking the bath evil spirits can be driven away. Although shobu (iris) is linked to 'shobu' (win or lose) and 'shobu' (martial spirits), it is originally a medical herb. It is believed that medical herbs have a magical sense and wearing them is good for health as the saying 'fukuyaku' (taking medicine). Most of the dyes such as ai (indigo plant), akane (madder) and kihada (Amur cork tree) are medical herbs. Therefore, shobuyu means taking a hot bath with a medical herb as a folk remedy. And it is an example as that a folk remedy came to be tied up with an annual event. One of the similar example is yuzuyu (a hot citron bath) on winter solstice. In addition, shobuyu is a kigo (season word for haiku, Japanese 17 syllable poem) for summer.