May 5th is known as Tango no Sekku, more commonly known today as Boy¡¯s Day. It is a day to pray for the healthy growth of boys. People raise koinobori in their yard, eat kashiwa mochi and chimaki, and soak in shoubu bath. This is probably the common way of spending the day.
This tradition came from China, but carried out a little differently. Originally they would hang shoubu and yomogi or put them in baths. The shoubu has a strong fragrance, and it was used to keep evil spirits away. However, since the Edo period, they associated shoubu the flower with the idea of valuing martial arts and military affairs, which is also pronounced ¡°shoubu¡± in Japanese. Therefore they correlated that with hoping for boys¡¯ healthy growth and advancement, and that is how the event changed from chasing away evil to a boys¡¯ celebration. The raising of the koinobori originates from the Chinese legend that a koi swam up the rapid waters of a waterfall known as Touryu. One can see that this koinobori and the armor and helmet decorations all connect to the hope that the boys would survive and prosper through their tough lives.
The kashiwa mochi that people eat on this day is made of anko that is surrounded by mochi that is mixed with joushinko and katakuriko (potato starch) and wrapped with kashiwa (oak) leaf. The oak leaves do not fall until new buds show, and they symbolize that the parents do not die until they have offspring, representing the safety of the family name.
The elegant and aristocratic practice of bathing in shoubu baths evolved, with the rise of bushi, to a realistic event that prays for military success, continuing the family line, and advancing in careers. Either way, the boys today and in the past had to live through hard times that accompanied the era. With that in mind, for parents who have boys, a day to wish for their well being might be more important than you think.