Ten days have passed since GANTAN (元旦), New Years Day. The round mochi rice cakes, which have been set in the family’s Shinto altar (kami-dana), in the alcove (toko-no-ma) of the Japanese style tatami room, or these days, on a book shelf, dresser, or counter-top, have become hard and dried out, cracked, and maybe even, if you check underneath, moldy. After all this time, they have also been able to absorb plenty of LIFE ENERGY from the Toshi-Gami-Sama (the God of the New Year) to whom these Kagami-Mochi were offered. It is traditionally believed that this energy can be transferred to anyone who ingests these Mirror Rice-Cakes (as literally translated). These days, however, most Japanese who keep the tradition of breaking up these flattish, round mochi cakes by hand or with a mallet, and eating them in O-zoni (soup), or O-Shiruko (a hot, sweet, azuki bean soup) do so out of tradition, and because it is fun and delicious.
Looking closely at this custom also sheds some light on Japanese culture and more importantly, traditional ways of thinking.
These days, the 11th of January has become the standard day on which to do Kagami-Biraki, which translated directly means OPENING THE MIRRORS, though, depending on the region, neighborhood, or household, it can take place on any day in mid-January (in my neighborhood the mochi is eaten on the 16 of January). In fact, originally, the mochi-breaking ceremony was held on the 20th day of the 1st month, until the third Tokugawa Shogun, Iemitsu, passed away on that date, and the day was changed to the 11th.
The round rice cakes were shaped to resemble mirrors because mirrors have been revered in Japan since ancient times and are believed to be receptacles of the gods. You might have seen mirrors set up inside the main halls of a Shinto Shrine. For the New Year, a smaller mochi is usually placed on top of a larger one (on rare occassions there are 3 mochi cakes in a stack !). Sometimes the Kagami-Mochi are further embellished with significant decorations such as a citrus called a daidai (which is a homophone for generation after generation), a spread open folding fan (to symbolize the spreading of your seed), kelp (konbu), which is a near homophone to YOROKOBU (to enjoy). There might also be other plants (all with symbolic meanings) and folded red and white paper (to keep out impurities) used to decorate the mochi.
The reason the hard mochi is broken and not cut is that the SAMURAI avoided using the word CUT, as well as the symbolic action of cutting, especially around New Year’s. Thus a knife is not used, And, even though the Kagami-Mochi is BROKEN, the word WARU (割る), to break, was also avoided (the SAMURAI did their best to avoid being cut or broken!). Instead, an IMI KOTOBA (忌み言葉), a euphemism, is used: hiraku (開く) to open. And thus this custom came to be known as KAGAMI-BIRAKI (鏡開き) the OPENING OF MIRRORS, which sounds very auspicious.
This was originally a custom of the warrior class. But as is so common in Japan, whenever allowed to, the commoners quickly emulated the customs of the higher classes made them their own. among the general populace.
Apparently, during the Edo Period, families of the class however, also placed and left New Year`s rice cakes on their armout and helmets, and in the case of the women- on their mirrors! This custom has not survived
These days Kagami Mochi ceremonies can also be seen at weddings and other happy occasions.
And a recent INNOVATION in Kagami mochi marketing has been to sell them in see-through form- fitting plastic packets so that the rice does not get mouldy. It is opened on the 11th and is as fresh as it was on the day it was made.
If you have been in Japan on the weeks leading up to O-Shogatsu you have surely seen them if you have been to a supermarket or convenience store.
I have also written a Tsukublog article about HANABIRA MOCHI, an unusal Japanese sweet which is eaten at this time of year- especially by practioners of the TEA CEREMONY: