I've searched the web for hours, including a great site http://www.oldandsold.com/pottery/ for pottery marks. Searched every country and never found initial jp. They are stylized cursive, not block. Anyone have any info? Contact crittercountrytrl-dbr@yahoo.com NO SOLICITORS PLEASE.
http://marksfinder.com/category/initials-names/j-initials-names/