A Local Perspective on Life in Tsukuba, Ibaraki, Japan.

KAGAMI BIRAKI (鏡開き)- Breaking Open the Mirrors – a closer look at how and why the Japanese break open and eat the New Year`s Kagami Mochi rice cakes on January 11th (again)

A Kagami Mochi consisting of three rice cakes, an orange, skewered dried persimons, kelp, and various leaves (sakaki, yuzuriha, and urujiro)


And another KAGAMI MOCHI- in its purest form- two plain mochi rice cakes (at a home in Sasagi, Tsukuba- January 9, 2016)

And another KAGAMI MOCHI- in its purest form- two plain mochi rice cakes (at a home in Sasagi, Tsukuba- January 9, 2021)


By Avi Landau

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, a little moldy. After all this time, (according to traditional beliefs) it has 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 old custom of breaking up these flattish, round mochi cakes by hand or with a mallet, and eating them in O-zoni (soup), or O-Shiruko/Zenzai ( hot, sweet, azuki bean soups) do so out of tradition, and because it is delicious and fun.

Kagami-Mochi in see-through plastic packages on sale before O-Shogatsu. These rice cakes don`t get moldy, they are kept in their packs until they are eating for KAGAMI BIRAKI

Kagami-Mochi at small shrine in Tsukuba

Mochi rice cakes offered at small shrine in Tsukuba

A week after being set out in the open, the rice-cakes often crack – especially in the Kanto Region where the winter air is very dry (at a roadside shrine in Shimana, Tsukuba 2021)

Looking closely at this custom helps shed some light on Japanese culture and 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, this event can take place on any day in mid-January (in my old neighborhood, Hojo, 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.

Small shrine in Tsukuba
Small shrine in Tsukuba


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- representing the Yin and the Yang (on rare occasions 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 and made them their own.

Apparently, during the Edo Period, families of the warrior class also placed and left New Year`s rice cakes on their armor and helmets, and in the case of the women – on their mirrors – though this custom has not survived.

Interestingly, while it is only white rice-cakes that are used for Kagami-mochi, those in the city of Kanazawa, Ishikawa Prefecture (formerly the territory of the Maeda Clan) use festive red and white (KO-HAKU) - no one is sure why, but one guess that it was a little show of rebeliousness during the Tokugawa Family rule of the Edo Period (since the Tokugawa color was white)

Interestingly, while it is only white rice-cakes that are used for Kagami-mochi, those in the city of Kanazawa, Ishikawa Prefecture (formerly the territory of the Maeda Clan) use festive red and white (KO-HAKU) – no one is sure why, but one guess that it was a little show of rebelliousness during the period of Tokugawa Family rule of the Edo Era (since the Tokugawa color was white). I took this photo from the web: blog.goo.ne.jp

These days Kagami Mochi ceremonies can also be seen performed at weddings and on 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 moldy. It is opened on the 11th and is as fresh as it was on the day it was made.

Note how the rice-cakes are encased in plastic – to prevent mold an cracking (at the Kisoji restaurant in Tsukuba, 2021)

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 an article about HANABIRA MOCHI an unusual Japanese sweet which is eaten at this time of year- especially by practitioners of the TEA CEREMONY.



  • Lisa Uzunoe says:

    Hello, I would like to ask where you found this info on the kagami bikari as it is very interesting and would like to be able to share it as a part of our community Mochitsuki festival (Portland,OR). We offer Okagami mochi at our church/shrine and I’m always trying to explain traditions. Thank you!

  • Avi Landau says:

    Hello Lisa, and thank you for reading Tsukublog. I`m glad that you find the articles on Japanese culture interesting and useful.

    The articles you read are created through a long process. They are amalgamation of all the Japanese source materials that I can find on the subjectat the library or in my own book collection. There are
    whole shelves of such books ( on traditional customs) at any library in Japan, and over the years I have read MANY ( if not MOST) of these.

    Then I spend alot of time with each topic asking Japanese people of different ages, from different backgrounds and from different regions about what
    come to their minds when they think about KAGAMI MOCHI etc….

    I hope you keep consulting Tsukublog when you have a question about Japanese culture. I do my best to to give the most comprehesive explanations in short and readable articles.

    All the best to everyone in Portland!

    Avi Landau

  • Christine Parkinson says:

    Dear Avi,
    thank you for an interesting article, as ever. I was fascinated when I read it, as I have heard of the expression ‘kagami biraki’ before, but meaning to break open a barrel of sake as an auspicious way to open an important event.
    I would love to hear more about the sake version of kagami biraki, and also to know whether there are any other forms of ‘opening of mirrors’, apart from with rice cakes or sake?
    kind regards,

  • alice says:

    I really admire you. You have kept on writing for so many years although many have quit blogging. Whether your posts are rewrites or re-posted , there are people who read them. Very informative and there are things which not all Japanese know about. Thanks for the effort in putting up your posts.

  • Avi Landau says:

    Hello Christine and thank you for writing!
    The word BIRAKI (to open), is attached to other nouns besides KAGAMI (which means mirrors). For example there is YAMABIRAKI (山開き) – the opening of a mountain to climbers (the most most famous of these being on July 1st for Mt. Fuji) and UMIBIRAKI (海開き)- the opening of the beach to swimmers in summer, and I will just give one more example, something I wrote about last week- the HABA-BIRAKI- which was the opening of Tsuchiura`s Yachting Club for the first time in the new year.

    This is just what I can think of off-hand, but if some more good ideas come to mind, I will post them as comments here.

    Once again, thanks fpr writing- and hope to here from you again!

  • H M says:

    Hi Avi. Happy New Year! I want to tell you about a regional variation
    o the kagami mochi customs. My hometown is Isahaya in Nagasaki Prefecture. Every year on New Years Day, Each members of my family
    puts their hands together and prays to the rice cakes. After doing so we each, in turn, pick off a tiny bit of the rice with our finger-nails
    and then put it in our mouths and swallow.
    To tell the truth, I don`t know if it`s a local custom or just our family custom. Next time I go back home I will ask my old friends and neighbors about it.

    Thanks for the good post