Porcelain manufacturers used a variety of symbols, letters or images to denote their products. Called backstamps, these markings may be found on the bottom of a vase, on the back of a plaque, or on the bottoms of utilitarian items such as bowls, plates, saucers or cups, etc.
There are approximately 359 Nippon back stamps known to date. Most of these are documented in Joan Van Patten's The Collector's Encyclopedia of Nippon books. Go to Nippon Publications for a complete listing of books available.