Mochi is the traditional Japanese confection or a rice cake, made of glutinous, sticky rice. Respective prefix "o" is often used while speaking about mochi.
Sometimes these balls are dipped into a soy bean powder kinako, or filled with manju, red bean paste. Mochi can also be dipped into a soy sauce and eated with a seaweed, but I never tried that. Often you can see mochi that is served on wooden stick, like a barbeque. (see picture below)
in Japanese family, mochi is made for special occasions such as new years day or someone's birthday, just to mention few. In postwar Japan, during the poor days, mochi was a special delicasy that was rarely available.
Mochi is also a great dessert, especially with Japanese green tea, ocha.
Special packages of mochi can be bought at the railwaystations all over Japan to bring back home as omiyage, a Japanese present.
Another type of Japanese traditional confection is called Wagashi.