Knowledge about Japan
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In Japan, it is customary for families with boys to decorate carp streamers around May 5th every year.
It is said that Koi Nobori (carp streamers), regardless of the environment, good or bad, were decorated in the hope that they would grow up and achieve success in life.
In the Edo period (1603-), there was a custom in Japan of a samurai family to celebrate the birth of a boy by putting up a horse mark or a banner in front of their entrance.
This spread to the general public, and carp streamers began to be erected, and carp streamers were invented by the common people.