Instructions
Turn the piece over and inspect the bottom. This is where the NAPCO transfer mark can be found. If you are purchasing online, request a picture of the Napco transfer mark from the seller.
Inspect the sides of the piece. Napco used transfer marks as well as paper labels. A paper label should read, "A Napco Collection," "Napco originals by Giftware," "National Potteries Co., Cleveland, OH, Made in Japan," or "Napcoware, Import Japan."
Identify the Napco sticker or transfer mark. The transfer mark should be under the glaze of the piece and read "NAPCO" or "Napco China." Numbers were also used to identify specific pieces, like an item number. Make sure this item number corresponds to the piece you are seeking.