A type of speciality food store that has almost disappeared from the streets of Japan is the kanbutsu-ya (dried-foods store). These days we can get fresh produce all year round, but that wasn't the case before canning and refrigeration became widespread. To cope with the lack of fresh ingredients in winter, especially in colder areas of the country such as the Tohoku region, people turned to foods that were preserved though pickling, salting, fermenting or drying.
There are only a handful of standalone kanbutsyu-ya left, but you can still buy all kinds of traditional dried foods at supermarkets, department store-food halls and by mail order. There are dried-seafood products, dried seaweed (nori, konbu, hijiki and more), dried beans and dried fruits. Dried vegetables in particular have seen a bit of a renaissance in recent years as a healthy and low-calorie way of incorporating more fiber into everyday meals.
The most useful dried food may be mushrooms. Quality dried shiitake mushrooms are so full of flavor that the soaking liquid can be used as a soup stock. The rehydrated mushrooms are great in nimono (simmered dishes), stir-fries and winter hot-pots, as well as in sushi, as part of a roll filling or mixed into chirashizushi.