The traditional way to make Mochi is as follows. At first, glutenous rice called 'Mochi-gome[糯米（もちごめ）]' is steamed. Then that is pounded with Usu[臼（うす）](mortar) and Kine[杵（きね）](pestle) by two or more persons. One person pounds Mochi-gome, which is put into Usu, with Kine one or several times. After that, another reverses it while sometimes moisturizing with wet hands with water. And Mochi is made by repeating that many times. Making Mochi in this traditinal way is called 'Mochitsuki[餅つき]'.
Kine and Usu
Mochi-tsuki of Nakaya-dō: Nakaya-dō is a Yomogi-mochi shop in Nara and that is famous for a performance of high speed Mochi-tsuki.
Mochi was used as an offering to gods because Japan is a country of rice culture and that is the most important crop. Therefore, Mochi has come to be eaten at the seasonal and celebratory events.
At Shōgatsu[正月（しょうがつ）](Japanese New Year), Mochitsuki is held for making Kagami-mochi[鏡餅（かがみもち）](rice cake for display). Kagami-mochi is an offering and that is displayed in the house during Shōgatsu. And that is taken away on January 11th(or 20th or some day, it depends on the region.) and the Mochi is eaten. That event is called 'Kagami-biaki[鏡開き（かがみびらき）]'.
Mochi has a sticky texture and Mochi is mainly eaten by toasting or boiling. That is used for various dishes. For example, Mochi is eaten as an ingredient of Nabe[鍋（なべ）](pot dishes) and Zōni[雑煮（ぞうに）](soup dish of various ingredients seasoned with soy sauce or Miso[味噌（みそ）]). And a hot sweet, Oshiruko[御汁粉（おしるこ）](Zenzai[善哉（ぜんざい）]) is also popular, that is a soup of Anko[餡子（あんこ）](red bean paste) and Mochi.
Besides them, there are Isobe-mochi[磯部餅（いそべもち）](Mochi seasoned with soy sauce and rolled in seaweed, Nori[海苔（のり）]) , Abekawa-mochi[安倍川餅（あべかわもち）](Mochi coated with sweetened soy bean powder, Kinako[きな粉]) and Zunda-mochi[ずんだ餅](Mochi coated with sweetened and mashed Edamame[枝豆（えだまめ）]).
Kusa-mochi[草餅（くさもち）] is a Mochi pounded with Yomogi[蓬（ヨモギ）](mugwort) and that has an unique smell of Yomogi. Okaki[おかき] is a dried, seasoned and toasted Mochi. That is a kind of Senbei[煎餅（せんべい）](rice cracker).
There are Mochi made from the rice powder. Sakura-mochi[桜餅（さくらもち）] is a sweet made from Mochi-gome powder and that is the Mochi with a filling of Anko wrapped with a leaf of Sakura[桜（さくら）] pickled in salt. Kashiwa-mochi[柏餅（かしわもち）] is a sweet made from non glutinous rice powder and that is the Mochi with a filling of Anko wrapped with a leaf of Kashiwa[柏（かしわ）](oak).
(That is made from non glutinous rice powder and is a specialty of Niigata Prefecture)
Gyūhi[求肥（ぎゅうひ）] is a kneaded Mochi-gome powder with sugar or syrup. Gyūhi is a material of Wagashi[和菓子（わがし）](Japanese sweets) and that is used for various sweets.
(That is a sweetfish-shaped sweet and Gyūhi is used as a filling.)
In addition, the word 'Mochi' is used for some sticky foods. Kuzu-mochi[葛餅（くずもち）] is made from the starch of the root of Kuzu[葛（くず）](arrowroot). Awa-mochi[粟餅（あわもち）] is a food made from pounded Awa[粟（あわ）](foxtail millet).
The shape of Mochi varies with regions. Mainly, square Mochi is eaten in eastern Japan and round Mochi is eaten in western Japan.