What's interesting is that you can tell how old your piece is by the code on the bottom. For instance this Walker China cup has a code of J-47. This means it was produced in January 1947.
Buffalo China has a unique code of its own, J-12 means that this stack of small diner plates was manufactured around December 1949.
I think my favorite marking would have to be the raised buffalo logo mark, which is most likely from the 50's or 60's.