Abstract: Playing cards that include a machine-readable bar code in the form of a number of mutually parallel and juxtaposed bars, wherein the code is adapted to be read by light sensitive detectors. Each playing card includes at least one six-position binary code in which a bar is either present or absent at each of the six positions. The code includes a reference code in the form of an additional bar in at least one further position adjacent to the six-position binary code. The reference code is positioned for detection by a light sensitive detector. The binary code is intended to be read by means of the light sensitive detectors when the existence of the reference code is detected.

Abstract: A device for registering and presenting bidding in a game of bridge comprises a computer unit (1-5) which includes at least one bid-entering keyboard (2-5), elements for comparing the entered bid with bids permitted by the rules of bridge, elements for preventing impermissible bids being presented, elements (1) for registering entered bids, and elements for presenting or displaying the entered bid.