Q: I bought this chop plate at an antique show and would like to know how old it is and what it's worth. The backstamp says it was made by Edwin M. Knowles China Co. and the shape is called Yorktown. What is the pattern?
A: Edwin M. Knowles China Co. was founded in Chester, W. Va., in 1900. The plant moved to Newell, W. Va., in 1931. It went out of business in 1963, but an overseas company bought rights to use the name and used it on new dishes. Knowles didn't include pattern names in its marks until the late 1940s, but the shape name and a date code were included. The numbers "38-11" in the mark on your plate indicate your Yorktown-shape plate was made in November 1938. The pattern, called "Penthouse," was introduced in about 1936. The value of a chop plate like yours is about $20.