Japan shares the Asian tradition of rice cakes: glutinous rice that is pounded into a paste and shaped. In Japan, it is called mochi, or more usually the honorific o-mochi.
The tradition of mochimaking, or mochitsuki, has been an important one in Japan, and, is associated mainly with New Year in Japan, when mochi forms one of the most important Japanese foodstuffs of the season, in the form of "kagami-mochi" (lit. "mirror rice cake"), a stack of round or oval rice cakes which are placed on a Shinto shrine (a Shinto shrine always featuring a mirror).
Mochitsuki is a two-person task, one turning the rice between slow rhythmic pounds with a wooden mallet by the other.
Mochi retains its ceremonial role in Japan, but is much more familiar to people as an ordinary snack purchasable at convenience stores, supermarkets and department stores.
There are dozens and dozens of different kinds of mochi available in Japan, featuring numerous different shapes, sizes, fillings, coatings, and consistency.
The o-mochi featured here are basically shiromaru mochi ("round white rice cakes"), the kind used for the New Year kagami mochi referred to above. As you can see in the second photo, they are filled with that most popular of o-mochi fillings, bean paste, or anko.
Note, also, the two different colors of mochi here: white and green. The white mochi is made of rice pounded as is, the green, known as kusamochi "grass rice cake," is colored by adding yomogi (Japanese mugwort) to the mix.
The universal sensation provided by all mochi, whatever the variety, is that distinctive soft, elastic, chewiness—something like a cheekfull of plump, giving, digestible chewing gum that rolls around, rendering your whole mouth slightly helpless feeling, until your top and bottom teeth finally find each other again, and that once pillow-like little packet of pudge is now chomped up and hydrated enough now to swallow in smooth fleshy gobs. Tengoku da yo! ("Heavenly!")
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