Secret Rule

About

Secret Rule is a concept rooted in game design and inductive reasoning. The term originates from Eleusis, a shedding-type card game invented by Robert Abbott in 1956. In this game, one player establishes a secret rule that determines which cards can be played on top of others, while remaining players use inductive logic to discover the rule through gameplay. The game was first published by Martin Gardner in his Mathematical Games column in Scientific American magazine in June 1959, with a revised version appearing in Gardner's July 1977 column. Eleusis is often regarded as an analogy to the problems of scientific method, as players must observe patterns and form hypotheses to uncover the hidden rule. Similar games featuring secret rule discovery include Mao, Penultima, and the commercially produced Zendo, where a designated Master or spectators declare plays legal or illegal based on predetermined rules that players must decipher inductively.