Today, 11th of January is Kagami-biraki (鏡開き) in Japan. It´s the day people break (開く/Hiraku/ open) Kagami-mochi which has been decorated during the New Year.
In the western part of Japan, they do it on the 15th and in Kyoto and surrounding area do it on the 4th of January. There are some differences in the region but 11th is the most common for Kagami-biraki.
In martial arts Dojo they seems to have Kagami-biraki with Hatsu-geiko (first training day). A friend was practicing Aikido and I once went with her because she told me that they would give us Oshiruko (お汁粉). I just went without even knowing what exactly Oshiruko was. I was probably 6 years old and in my house, my parents rarely gave me sweets. Whereas my friend was a daughter of a traditional Japanese sweets shop and was more familiar to sweets.
When we arrived at the Dojo, I was a little scared. There were many kids in Dogi (道着/clothes for martial arts) and practicing. Like any martial arts, practitioners make noise with Kiai (気合い/spirits) but it scared me. I was sitting and watching them in the corner of the Dojo but wanting that to end. I only came to eat Oshiruko.
Oshiruko was Mochi in the sweet Azuki bean soup. You can eat it any time of the year. Usually Mochi is fresh and soft but since Kagami-mochi has been in the air for more than a week, Mochi becomes dry. I guess my first Kagami-biraki in Dojo disappointed me a little.
Why it´s important to eat Kagami-mochi although not as good as fresh Mochi?
Ancient people believed the food once being offered to the God would have a special power and by eating it with the appreciation to the God, they wished for a health during the year.
In my house, the day before my father would told me to bring Kagami-mochi down and to curve the mould off. Usually after nearly two weeks, it was moulded. Since my father is an old-fashion guy, he thought it was OK after getting rid of the mould on the surface. Of course, penicillin saves people, doesn´t it? Our Oshiruko had always sharp point in the taste rather than just sweet. I suppose my not liking blue cheese comes from this experience.
One day in the biology class, the teacher told us that the mould is not only on the surface but its roots take over entire food. Eek, no wonder Kagami-mochi tasted like mould. The first thing I told my father when I returned home was the new knowledge about mould. And since then, we didn´t need to eat moulded Mochi. Thanks teacher.
Usually people just bring down Kagami-mochi and break into pieces before cook. But you can also put them in the water to soften it and make rectangular mochi just like biscuits with a rolling pin. You need to keep them in the water for a few days by changing the water every day. Like this, you can avoid tasteless dry Mochi.
The most important thing when you break Mochi into pieces is never cut it. It reminded Japanese people Seppuku (切腹) in the old time and they believed it as a bad luck.
The common way is to break it with a wooden hammer or do it with your hands.
It doesn´t have to be Oshiruko, you can cook it in a savoury soup, bake or fry. In any way, by eating Kagami-mochi brings you a good health.
Recently many people live alone and don´t have any New Year decorations in the house. Each year less people seem to celebrate Kagami-biraki but it is a Japanese tradition in the New Year. I myself couldn´t do it but something I don´t want to forget either.
More about Japanese New Year