Mochi is made by pounding steamed sticky rice with a heavy wooden mallet in a large mortar. Freshly pounded mochi is soft and stretchy in a way packaged mochi never is. At these shops you watch it being pounded and eat it while it is still warm.
Every morning the owner pounds mochi by hand at the shop front, and you eat it inside: try kogashi shoyu mochi, toasted with soy sauce, or a set of several kinds of fresh mochi. It is in Nagoya, a shinkansen stop between Tokyo and Kyoto, near Shiogamaguchi Station on the subway. Open only until early afternoon, and closed on Tuesdays and Wednesdays.
Two craftsmen pound mochi at astonishing speed, shouting in rhythm as one flips the dough between the mallet's blows; videos of it have been watched around the world. Warm mugwort mochi filled with sweet bean paste sells by the piece, for takeaway only. There are no set times, as they pound a new batch whenever the last one sells out; a 5-minute walk from Kintetsu Nara Station.
In a farmhouse built in 1954, you take the mallet yourself and pound the mochi, then eat as much of it as you like while it is warm. It is in the countryside of Fukui city, a 10-minute walk from Echizen-Togo Station, and Fukui is now on the Hokuriku Shinkansen. Mochi pounding is by reservation only, and it is closed on Mondays.