Much of my knowledge of Japanese ceramics has come from a single website, e-YAKIMONO.NET:
The site is run by Robert Yellin who also hosts the Robert Yellin Yakimono Gallery in Mishima City (Japan). I've found it to be an invaluable mine of information about the history of ceramics in Japan, and about individual potters, their backgrounds, styles and philosophies of working. There are also clear explanations of various traditional terms used, such as the "koudai" or "kodai" which means footring (of a tea bowl). On this page, the Author explains the importance of the kodai to the overall design of a tea bowl and provides images of many different pieces, demonstrating how each potter gradually develops a refined and distinctive way of forming the footring:
Visit the e-Store section of the website, and you'll find an online gallery containing a vast repository of images of works for sale and an archive of sold pieces. The thing I really enjoy about this part of the site is that every ceramic piece has been photographed from multiple angles, so you can really get a good idea of how the pot would feel in the hands. Some of the pieces shown here are truly spectacular works of art and I am often left wishing I could have watched and learned from the artists as they created them.