Instructions
Research the history of Japanese signatures and marks and familiarize yourself with some basic knowledge to help you make an informed decision on the piece you are looking at.
Purchase a pictorial guide to marks such as Chad Lage's "Pictorial Guide to Pottery and Porcelain Marks," or "Miller's Pottery &Porcelain Marks: Including a Comprehensive Guide to Artists, Makers, Factories and Forms."
Examine the piece closely for all signatures and marks. As well as looking on the bottom of the piece, check for markings inside the piece and within the decoration itself. Twentieth-century mass market pieces commonly feature English words such as "Noritake" and "Nippon" which mean they are from Japan. The word "Nippon" was used until 1921, when the U.S. government insisted that imports for the U.S. market be marked "Japan" instead. The phrases "Occupied Japan" and "Made in Occupied Japan" mean that the pieces were made between 1945 and 1952.
Compare the signature and marking with the many examples in your pictorial guide, or at the website www.gotheborg.com. This is the best way for an amateur to home in on the origin of a piece. You will soon become familiar with some simple marks, such as a mark within a fan which means it is Izumi ware; the image of Mount Fuji and a stream, which means it is Fukagawa ware; and rising sun motifs which date pieces to the late 1940s.
Take a photo of the signature and markings and consult more than one expert, if you want to definitively identify a piece, prior to purchase.