Kodomo No Hi: A Guide To Children’s Day In Japan

The Koinobori, The Armor & The Food Explained

This Sunday, we're celebrating Children's Day!

Things change quickly in Japan and as soon as Hinamatsuri (Girl’s Day) is over, the country starts preparing for Golden Week — and even more specifically, for Children’s Day. You may have noticed that your neighborhood is more active than usual, gearing up for something special. To the untrained eye, it seems like an odd affair — colorful carp-shaped flags hoisted from balconies and ominous-looking samurai armor adorning family living rooms.

That’s right, May 5th in Japan is Children’s Day. And here’s our guide on how to celebrate it like a local.

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The Origins of Kodomo No Hi

The 5th of May was originally known as Tango no sekku and is the Japanese equivalent of the Double Fifth, a holiday celebrated in many Chinese households around the world. In 1948, the government changed the official name to Children’s Day. However, even though it’s officially known as Children’s Day, most Japanese still consider and celebrate the “double fifth” as Boy’s Day. This seems only fair as Girl’s Day is celebrated on the “double third” (Hinamatsuri) — though Girl’s Day is not an official public holiday. 

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How is Kodomo no Hi celebrated?

Families that have a boy will hoist carp flags outside their homes and you’ll see the same in various public places across the country, too. The carps are the symbol of the holiday.

According to an ancient Chinese legend, a mixed school of fish tried to fight their way up a waterfall called “Ryumon,” or dragon gate. While all the other fish gave up and drifted downstream, the carps persisted, and once inside Dragon Gate, they transformed into dragons. While there are different versions to this age-old tale, the Japanese version ripened into a proverb — koi no taki-nobori. I’m going to go out on a limb and guess that that folk wisdom was shortened into “koinobori,” the modern name for the famous carp flags.  

The annual Children’s Day Festival at Tokyo Tower oversees hundreds of carp flags in celebration of the holiday.

The black carp, the largest one on the koinobori flag, represents the father and is known as the magoi. The red carp represents the mother (higoi), and the last carp (often blue) represents the child (traditionally the son) with an additional carp added for each younger sibling.

The black carp, the largest one on the koinobori flag, represents the father and is known as the magoi.

The Armor And The Beetle

Families celebrating Kodomo no Hi will also decorate their homes with a samurai armor and a helmet miniatures, representing their wishes to raise strong and powerful boys. The armor (yoroi) and helmet (kabuto) form the word yoroikabuto, which you will hear often around this time of the year. 

Those of you studying Japanese may find a useful mnemonic in the word for helmet — kabuto — which sounds an awful lot like the kabutomushi (Japanese stag beetle) and in my eyes bears more than a passing resemblance. The kabuto was the inspiration behind Darth Vader’s helmet and the traditional versions still retain a sense of that menace.

Special Dishes

Traditionally, like most Japanese holidays, there are special foods that go with every occasion, and Children’s Day is no exception. Japanese people cook chimaki for this holiday — a rice cake made out of steamed sticky rice, or mochigome, wrapped in a bamboo leaf, and kashiwamochi — a sweet Japanese treat. Here’s how to try your own.


  • 3 cups of mochigome or glutinous rice (can be purchased at any supermarket). Rinse and leave in colander for 30 min. before cooking.  
  • Cooked pork, 150g (cubed, about 1cm)
  • Dried baby shrimp, 20g (rehydrated and coarsely chopped, keep liquid)
  • Dried shiitake mushroom, 4-5 (rehydrated and cubed, about 1cm, keep liquid)
  • Bamboo shoots, 100g (cubed, about 1cm)
  • Carrot, half (cubed, about 1cm)
  • Shiitake and shrimp liquid, about 3 cups
  • Soy sauce, 1 tbsp
  • Sugar, 1tsp
  • Oyster sauce, 1 tbsp
  • Cooking sake, 2 tbsp
  • Salt, 1/2 tsp
  • Pepper, a pinch
  • Sesame oil, 2tbsp
  • Bamboo leaves, 10 (wiped down with a damp cloth)

In a large pot, heat the sesame oil and cook the rice and all other ingredients (besides the seasonings and liquids) for three minutes. After the rice starts to glisten, add all the seasonings and the liquids to the same pot. Stir constantly until liquid is gone. Be careful not to burn the rice at the bottom. Then wrap the mixture with the bamboo leaves, make triangles and tie with thin bits of the leaves. Steam for 10 minutes on medium heat. Turn off the heat and keep the lid on for an extra 10 minutes before serving.


This Japanese sweet (wagashi) calls for the seasonal kashiwa oak leaf to wrap the rice cakes in. This leaf gives its distinct look and name. The name of the rice cake can vary according to whichever leaf it may be wrapped in. Here’s what you need to cook it: 

  • Jyoshinko (a fine/high grade rice flour, available in any Japanese supermarket), 250g
  • Water, 350cc
  • Koshi an (smooth sweet bean paste) or ogura an (sweet bean paste with whole beans), 300-350g (rolled into balls the size of plums, about 30g each)
  • Kashiwa oak leaf, 10 (washed and dry patted)

In a heatproof glass bowl, add the flour and water. Mix well. Cover with cling film and microwave for five minutes and 30 seconds at 600w.

Knead 15 to 20 times on a large piece of cling film. After kneading, put the dough in a Ziploc bag and chill it on iced water for about 20 minutes. Make sure to not get any water in the bag. After it’s chilled, knead it four to five more times. Then break it up into about 10 pieces (about 50g each). Roll them out so they look like stretched pennies, put the anko onto one end of the oval and fold it over, pinching the edges together. Cover the less attractive side with the kashiwa oak leaf and voila!

Now you’re ready to set the table, raise your koinobori-flag and your glass to all children around Japan. Happy Children’s Day!