In late spring, if you look up at the sky in Japan, you might spot something colorful fluttering in the breeze—koinobori, or carp streamers. These fish-shaped flags are part of a traditional event called Tango no Sekku, or Children’s Day, celebrated on May 5th. Even though the holiday has passed, the image of koinobori dancing in the wind still lingers as a beautiful memory of the season.

Why Carp?

Carp (koi) are known in Japan for their strength and determination—they can swim upstream and even leap up waterfalls. Because of this, they’ve become a symbol of perseverance and success. Koinobori are flown in the hope that children will grow up strong and healthy, just like these spirited fish.

Traditionally, families hang a large black carp for the father, a red one for the mother, and smaller, colorful ones for the children. In modern times, you might see mini versions decorating balconies or even used as festive decorations indoors.

More Than Just Decorations

Children’s Day is about more than just koinobori. Families often display samurai helmets or armor figurines (called Gogatsu Ningyo) and eat special treats like kashiwa mochi (rice cakes wrapped in oak leaves) or chimaki (sweet sticky rice wrapped in bamboo leaves). These traditions are meant to celebrate children’s happiness and health, and to share time together as a family.

In many workplaces and schools, koinobori-themed activities or events are also held, turning the whole season into a joyful, community-focused celebration.

As May comes to a close, the koinobori are taken down until next year—but the image of them flying high above parks and rooftops remains a cheerful reminder of spring’s energy and tradition.