Kodomo no hi
Kodomo no hi (こどもの日) is a Japanese national holiday which takes place on May 5th. It is a day set aside for to respect children's personalities and to celebrate their happiness.
It was originally called a Tanngo no Sekku, and was at first not held specifically on May 5th. It is said that this date was set after the Nara period.
On this day, families raise the carp-shaped Koinobori flags and display the traditional Japanese helmet, Kabuto. The Kabuto is the symbol of a strong and healthy boy: although it is not exactly said so, Kodomo no hi is generally said to be a "boy's day". (The girl's day is Hinamatsuri.) We also eat mochi wrapped in the leaves of Kashiwa on this day.
It is said that the Tanngo no Sekku was originally started in ancient China. From the beginning of history, May was said to be a month for purification, and many rites that were said to drive away evil spirits were performed in this month.