Tango no Sekku (端午の節句), also known as Ayame no hi (Iris festival), is one of the five annual ceremonies that were traditionally held at the Japanese imperial court called Gosekku. It is the Japanese version of Double Fifth (5-5) and was celebrated on the fifth day of the fifth moon in the lunar calendar or Chinese calendar. After Japan switched to the Gregorian calendar, the date was moved to May 5th. The festival is still celebrated in China, Taiwan, Hong Kong and Macau as the Duanwu Festival or Tuen Ng Festival (Cantonese), in Korea as the Dano Festival, and Vietnam as the Tết Đoan Ngọ on the traditional lunar calendar date.
Tan (端) means “beginning” and go (午) is a simplified form of ⾺ (horse), referring to the Chinese zodiac name for the fifth lunar month. Days of the week also have zodiac animals. Thus, tango originally meant “the first horse day of the fifth month”. However, go is a homonym for 五 (five) in Japanese, so during the Nara period the meaning shifted to become the fifth day of the fifth month. Sekku means a seasonal festival involving doubles of date and month. There are five sekku, including O-Shogatsu (January 1), Hina Matsuri (March 3), Tanabata (July 7) and Kiku Matsuri (September 9th) along with Tango. Tango no Sekku marks the beginning of summer or the rainy season.
Although it is not known precisely when this day started to be celebrated, it was probably during the reign of the empress Suiko (593BCE –628 CE). In Japan, Tango no Sekku was assigned to the fifth day of the fifth month after the Nara period (8th century CE).
Until recently, Tango no Sekku was known as Boys’ Day (also known as Feast of Banners) while Girls’ Day (Hinamatsuri) was celebrated on March 3. In 1948, the government decreed this day to be a national holiday to celebrate the happiness of all children and to express gratitude toward mothers. It was renamed Kodomo no Hi (Children’s Day) and changed to include both boys and girls. Before this day, families raise the carp-shaped koinobori flags (carp because of the Chinese legend that a carp that swims upstream becomes a dragon, and the way the flags blow in the wind looks like they are swimming). Displays include a flag for each boy (or child), a Kintarō doll usually riding on a large carp, and the traditional Japanese military helmet, kabuto. Kintarō and the kabuto are symbols of a strong and healthy boy.
Kintarō (金太郎) is the childhood name of Sakata no Kintoki who was a hero in the Heian period, a subordinate samurai of Minamoto no Raikou, having been famous for his strength when he was a child. It is said that Kintarō rode a bear, instead of a horse, and played with animals in the mountains when he was a young boy.
Mochi rice cakes wrapped in kashiwa (oak) leaves—kashiwa-mochi (mochi filled with red bean jam) and chimaki (a kind of “sweet rice paste”, wrapped in an iris or bamboo leaf)—are traditionally served on this day. The pounding process of making mochi originates from China, where glutinous rice has been grown and used for thousands of years. According to folklore, the first mochitsuki ceremony occurred after the Kami are said to have descended to Earth, which was following the birth of rice cultivation in Yamato during the Yayoi period (300 BCE – 300 CE). Red rice was the original variation used in the production of mochi. At this time, it was eaten exclusively by the emperor and nobles due to its status as an omen of good fortune. During the Japanese Heian period (794–1192), mochi was used as a “food for the gods” and in religious offerings in Shinto rituals performed by aristocrats. In addition to general good fortune, mochi was also known as a talisman for happy marriages. Here is a modern video of the pounding process as well as making of various styles of mochi: