It is sure that many foreign tourists expect to purchase fine Japanese potteries while staying in Japan. Then, you can find local potteries around Japan. However, there are more famous potteries in western/southern part of Japan than in eastern/northern part.
Probably the reason is that the technique and method of making potteries came from Korea or China, from the west. Also it is very important that the cray for producing the potteries are suitable too.
Although there are stores which sell wide range of potteries, it is better to visit the local pottery stores to buy them. Also there are many workshops which you can visit and make your own pottery.