In poker, baccarat, bridge, blackjack, and other card games, a dealer sets one or more decks of playing cards in a card shoe or the like, and deals cards to game players by drawing them therefrom one by one. In so doing, to ensure the fairness of the games, the cards need to be dealt at random. Therefore, a game host must sufficiently shuffle the playing cards randomly to ensure a random order of arrangement of the playing cards before they are set in the card shoe. The shuffled playing cards used in various card games such as poker, baccarat, bridge or blackjack will ordinarily include 416 cards if eight decks of cards are used.
A conventional card shuffling device for shuffling cards is disclosed in, for example, Patent Literature 1. Each shuffled playing card set is provided after being shuffled with a shuffling apparatus to be arranged in a unique order with a uniquely identifiable shuffled card ID affixed on its packing box or the like as a barcode.
Also, a technique for printing on each card used in a casino or the like the suit (type) and the rank (or number) of the card as a code in order to prevent counterfeiting is disclosed in Patent Literature 2 or the like.
Shuffled playing cards are dealt from a card shoe apparatus to be used in a game, and the code of each card dealt that represents its rank is read by the card shoe apparatus. In recent years, technology for counterfeiting cards has greatly advanced, and accordingly, illegal counterfeiting of cards with such code attached is no longer impossible. In a case where card itself is not falsified, a card which has regular code (qualified code) is illegally obtained. In such a case, before using the card for the game, this card can be mixed into a predetermined position among the shuffled playing cards. Further, in such a case, the falsified shuffled playing cards which is intentionally ordered can be wholly replaced for regular cards (8 decks of cards).