APPRAISER: It's porcelain ... the official mark underneath... GUEST: Mm-hmm. APPRAISER: ...that would indicate this was made for the court. GUEST: Hm. APPRAISER: We call that a reign mark ...

NOVA: And what makes Chinese porcelain so durable ... NOVA: Is it true that porcelain made for export didn't have reign marks and other types of marks? Wu: In general, yes, because export ...