I forgot to mention. Most of the cups have names carved into the bottom of them. You can see some in the photos. After cleaning, they become harder to see. They will darken as they get used.
Since most of the cups available were very similar, people used to have their names carved into the bottom of the cups, so they would know whose was whose. A lot of collectors here do not want the names in the bottom, but I prefer them because it adds a bit of history to each piece.
The owners would have their names put inside by the local pottery repair-man who would walk down the streets with his boxes of tools offering to repair broken pottery. The names were actually drilled into the bottom of the cups. A drill bit was used to put a series of little holes in the bottom to make up the characters.
Not all marked cups had names in them. Some had images, titles, or tea house names in them. These are less common.