Zendo

Zendo turns the scientific method into an elegant game of colorful shapes and secret logic. One player acts as Moderator and selects a hidden rule from the included cards. The other players are Students trying to discover it. The Moderator begins with two structures—traditionally called koans—marking one as following the rule and the other as not. On a turn a Student builds a new arrangement from crystalline pieces in three colors and three shapes, then either asks the Moderator to mark it or predicts how it will be classified. Correct predictions earn guessing stones, which may be spent to propose the complete rule. The challenge is not simply spotting a pattern but designing experiments that separate competing explanations. A structure with one carefully changed feature can reveal more than a spectacular pile of pieces. The Moderator never hints, rewards elegance, or changes the rule; every answer is just reliable evidence. Forty rule cards generate hundreds of possibilities across several difficulty levels, and experienced groups can invent their own. Zendo works competitively, cooperatively, and as a teaching model for hypothesis testing. The first Student to state the secret rule precisely wins.