To provide a card for a game and for a trade by which the content of which can be confirmed not only on a display but also at various kinds of places.

The card for the game and for the trade and its operation system has a means for adding visible or invisible information to a physical card and the electronic card, a means for reading added information and a means for using the read information for the game or trade are provided, consists of hardware and a software system for realizing theses means. The means for adding information to the electronic care is for capsuling processing or information hiding processing by steganography, and the information added to the physical card and the electronic card is linked and utilized.