Edo period

Koinobori (carp streamers) were originally displayed in samurai households during the Boys’ Festival (Tango no Sekku) to pray for children’s health and growth, and their origins date back to the Edo period. While there was already a custom in the Heian period of displaying May dolls and warrior dolls, koinobori only became widespread from the Edo period onward. Entering the Showa period, the custom of displaying koinobori spread even more widely across the country.

Wishing for children's health and growth

The reason we display carp streamers on Children's Day is to pray for children's health and growth. The image of a carp swimming up a waterfall is likened to a child's development and robust vitality, and families put them up as a custom to wish for their children's health and future success.

It depends on the family.

We display carp streamers to wish for children’s healthy growth and to celebrate their safe development. There isn’t a specific age for displaying them; it varies by family and region. The number of days they are displayed also follows local customs.

For the event/festival of Tango no Sekku (the Boys' Festival)

The custom of displaying carp streamers is closely tied to the event held on May 5th known as Tango no Sekku (the Boys’ Festival). Tango no Sekku originated in ancient China and is regarded as a rite to ward off evil spirits and pray for health and protection from illness. After it was adopted in Japan, the practice of displaying carp streamers on this day became a tradition to pray for the health and growth of boys.

You may display it.

Koinobori are traditionally displayed in the lead-up to Tango no Sekku, the Boys’ Festival on May 5, as part of an event meant to pray for children’s healthy growth. Whether you can display them does not depend on the child’s gender. Although Tango no Sekku has been known as a festival for boys, there is absolutely no problem with families who have girls putting up koinobori as well, since the meaning is to wish for children’s health and growth. In recent years, pink koinobori designed for girls have also been sold.

Ward off evil and protect the home

Each of the five colors of the streamers has its own meaning, embodying wishes to protect the family from misfortune and to drive away evil influences from the home. They are said to flutter in the wind to dispel negative energy and serve to safeguard the household.

Dad

The “magoi” in a koinobori is the largest carp streamer and symbolizes the father of the family. In the Edo period, when koinobori became popular, only a single black magoi was displayed, but today koinobori represent the whole family.

Because the image of a carp swimming upstream represents growth and success.

The reason carp streamers (koinobori) are modeled after carp comes from the Chinese legend of “Climbing the Dragon Gate.” In this tale, a carp bravely swims up a river’s rapids and eventually transforms into a dragon. Symbolizing overcoming hardship and achieving success, the story conveys wishes for children’s healthy growth. Inspired by the carp’s image, Japan began displaying koinobori.

A custom unique to Japan.

The origin of the Boys’ Festival (Tango no Sekku) is in China, but the custom of displaying carp streamers (koinobori) is unique to Japan. While various Asian countries have similar customs—albeit in different forms—that pray for children’s health and growth, the koinobori themselves are a distinctly Japanese tradition.

There are no particular rules.

There aren’t any strict rules about how long to display koinobori carp streamers. In many cases, they’re put up before Golden Week and kept up until Children’s Day on May 5, but some regions keep them up longer. In short, it depends on family and local customs, and it isn’t limited strictly to May 5.