A game playing system includes a use permission tag provided for use in a game disk for a user of a game, a disk drive, and a reproduction device for reproducing the game. The disk drive reads out a disk ID from the game disk. When the game is to be played, the reproduction device conveys the disk ID and a player ID to the use permission tag. The use permission tag stores the terms of use of the game and determines whether a combination of the disk ID and the player ID conveyed from the reproduction device fulfills the terms of use or not.