Throwing food is generally considered bad manners. But it is recommended on this particular day in Japan. Only roasted soybeans, not other foods, though. The day is called setsubun, and it’s usually February 3rd, depending on the Lunar calendar. Correctly speaking, the term setsubun (which literally means “seasonal division”) indicates the day before the beginning of each season, so there are four setsubun; Spring Setsubun, Summer Setsubun, Fall Setsubun, and Winter Setsubun. However, in Japan, the term usually refers to the Spring Setsubun, which is New Year’s Eve on the Lunar calendar, and Japanese celebrate the day yearly.
The celebration is accompanied by a special ritual to cleanse away all the evil of the former year in the Lunar calendar and drive away disease-bringing evil spirits for the year to come. This special ritual is called mamemaki (which literally means “bean scattering”). Roasted soybeans are thrown either out the door or at a member of the family wearing a mask of Oni (demon or ogre). The throwers chant “Oni wa soto! Fuku wa uchi!” The meaning of this chanting is something like, “Get out, Demons. Come on in Good Luck.”
The beans are thought to symbolically purify the home by driving away the evil spirits that bring misfortune and illness with them. As a part of bringing good luck in, Japanese customarily eat soybeans, one for each year of one’s life; if you are 27 years old, you eat 27 beans. In some areas, people eat one for each year of one’s life, plus one more for bringing good luck for the year to come; if you are 27, you eat 28 beans. Also, there are some regions where people bite into futomaki (big sushi roll) without cutting at all. They believe that your wish will come true if you bite into the uncut futomaki, called eho-maki. “Roll” symbolizes “rolling good luck in,” and to bite “uncut” represents the fact that your relationship will never be severed.