From the end of April to the beginning of May, there is a consecutive holiday period called "Golden Week" in Japan. Today, let's talk a little about the holiday on May 5th, which is known as "Tango no sekku" （Children's Day）
May 5th is traditionally called 'Tango no sekku,' and is also currently called 'Children's Day.' On this day, we celebrate boys' health and growth; while the Girls' Festival is known as Hina-matsuri (literally Doll's Festival) on March 3rd.
Tango no sekku originally started in the Nara period （710-794） at the Imperial Court of Japan, on the day of Tango, which was May 5th of Japan's old lunar calendar and marked the change of seasons, as a habit of taking a Shôbu-yu (bath in which bundles of Japanese iris are floating) and drinking Shôbu-sake (liquor in which an iris leaf is soaked), because it was believed that iris was good for health and had apotropaic effects.
Later, with the rise of the samurai (warrior) class, Tango no sekku came to be celebrated because the Japanese name of iris (Shôbu) is a homophone of their martial (Shôbu) ethos.
Eventually this event became prevalent in townsman society in the middle of the Edo period (1603-1868) as a celebration of the birth and growth of boys, and the custom of displaying a "kabuto" (helmet), which is also a symbol of samurai, has been passed down to modern times.