Abstract: The invention relates to a board game to test the deductive reasoning and logical thinking of two or three players. Each player is chosen in turn as code-maker and for each game selects, for example, five key playing pieces each displaying two characteristics, one of, say, shape and the other of, say, color. The other player(s) attempt to break the code by identifying the selected pieces by a process of logical deduction, involving the presentation of test playing pieces of both characteristics for checking by the code-maker.