5th of May is Kodomo no Hi (Boys´ Day) in Japan

Juju Kurihara

May 5, 20142 min read

Updated: May 10, 2023

5th of May is Kodomo no hi (こどもの日) in Japan. Parents and the family celebrate healthy growth for their male children. I know it says Kodomo and should be any children but in Japan it means boys. As we have talked some times, there is a girls´ day, which is on the 3rd of March (Momo no Sekku) but it´s not a bank holiday.

Since a little while, you see many Koinobori (鯉のぼり), flying carps everywhere in Japan. But why flying carps?

Let´s start with the origin of this event. Kodomo no hi came from China like many other annual events now celebrated in Japan and it was a ceremony for getting rid of even spirits. Since the rainy season started in May, avoiding illness or disasters were important. So people used irises to exorcise.

Before this event came from China, in Japan May was the most important month for planting rice. It was so sacred, only young virgin girls could plant rice for the ceremony. Then Chinese tradition came. People started purify the girls with irises before entering the rice field.

However when Kamakura period (鎌倉時代, 1185-1333) started, Samurai began to have more power. The sound of iris, shoubu was interpreted as fight (勝負), which has the same sound and the celebration was shifted to boys´ healthy growth.

Why carp? This also comes from Chinese old myth. It´s said that there is a very rapid waterfall in the Yellow River and the carps, which can swim up this waterfall would become a dragon.

In Japan, since carps can live anywhere and have strong vitality, they were symbol of success. People started hanging carps during Edo period (江戸時代, 1603-1868).

My auntie travelled to see my cousin´s son to celebrate Kodomo no hi together. Since 5th of May is during the Golden Week (A week of holidays) in Japan, it´s easier for the families to get together and celebrate this day.

I´ve collected different Koinobori around Japan. Some are hanged over the river, some are on top of the roof and some are hanged from a pole. Some are so big that you can walk inside.

But the most important thing is, all the families wish for their boys to grow healthy.