Shobuyu: Sweet Flag Bath for Boys’ Day on May 5

A few days ago, I posted an article about Kashiwa Mochi. “Kashiwa Mochi (柏餅)” is a traditional Japanese sweet for “Tango no Sekku (端午の節句)” or the Boys’ (Children’s) Day on May 5. 

Shobu Yu (菖蒲湯)

The day, May 5 is a national holiday in Japan when we celebrate boys’ healthy growth and wish for their future happiness, and have a traditional custom. The tradition is to have a sweet flag bath or “Shobu Yu (菖蒲湯)”.

The Origin 

Shobuyu Bath

The Japanese tradition of taking a sweet flag bath on May 5 has a long history. It is said that Shobu-yu originated from China, and in the Edo period (1603 – 1868), it became popular among common citizens.

Actually, the word meaning sweet flag in Japanese, “Shobu (菖蒲)” has another Chinese character pronounced in the same way “Shobu (尚武)”, which means to consider Japanese martial arts and military “Budo (武道)” an important thing.

Since “Shobu (菖蒲)” has the same reading as “Shobu (尚武)”, the people at that time began to use the plant for bathing on May 5 in the hope of what the word “尚武” stands for. In fact, since the old days in Japan, the sweet flag, Shobu has been believed to be a medicinal herb for driving away evil spirits.


Shobu Yu Sweet Flag Bath

The preparation of Shobuyu varies depending on each household, but in many cases, simply add sweet flag leaves to a bathtub of hot water.

Health Benefits

The plant, Shobu contains various essential oil components, such as Asarone and eugenol, so from Shobuyu you can expect the effect of relieving nerve pain and backache. What is more, the sweet flag has a distinctive aroma so you will relax during the bath.

(Reference Page: Wikipedia 菖蒲湯 )


Hi, I'm Tomo, a Japanese blogger living in Niigata Prefecture, Japan. For the purpose of enriching your life, I would like to introduce things about Japan on this blog, especially unique Japanese products, cooking recipes, cultures, and facts and trivia.

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