Sekihan: The Japanese Tradition of Eating Red Rice
In celebration of something, Japanese people traditionally prepare glutinous rice (Mochigome) cooked with Azuki red beans, called Sekihan (赤飯: meaning red rice).
The red-colored rice is eaten during celebrations or on auspicious occasions, such as New Year’s Day, Seijin no Hi (成人の日: Coming-of-Age Day), or Children’s Day (こどもの日: May 5).
Sekihan (赤飯): The Meaning of Red Rice in Japan
As for history, it is considered that there was a custom of offering red rice to deities in ancient Japan, and the cooked rice was distributed to people after the offering.
One primary reason why Sekihan is still offered to the deities or gods in Japan is:
people believe the color red has the power of driving away evil spirits, as you can see from Torii, the gate located at the entrance to Shinto shrines.
Also, the red rice has a religious meaning, sometimes prepared for bad news or deceased souls, even though we usually make it for celebrations or festivities.
When eating Sekihan, we sprinkle the sesame salt seasoning Goma-Shio (ごましお) over it, which also has a meaning.
In ancient times, Japanese rice took on a reddish color. But thanks to selective breeding, white rice has been a staple in modern times, and we don’t have natural red rice.
And for that reason, Sekihan is colored with Azuki red beans today. But in a sense, that is deceiving deities.
To deceive translates into Japanese as Gomakasu (誤魔化す), which includes the word Goma (ごま), meaning sesame.
Gomashio is the condiment associated with the phrase Gomakasu (誤魔化す), because of which the sesame salt is a necessity for modern colored Sekihan.
(Reference Page: Wikipedia 赤飯 )