In Zendo, one player is the Master and the remaining players are Students. Gameplay centers around the creation of certain objects called koans. In general, koans can be made up of all kinds of things from drawings of shapes to stacks of Legos. Starting out, let’s take our koans to be integers.

At the start of the game the Master comes up with a secret rule for koans to satisfy. Koans satisfy this secret rule if and only if thy have the Buddha-nature. The goal of the Students is to determine the secret rule.

Gameplay is as follows.

  • At the start of the game the Master comes up with a secret rule and presents a koan which satisfies the rule and a koan which does not satisfy the rule.
  • Each round a new Student creates another koan and declares whether the round is Master or Mundo.
    1. If the round is a Master round, then the Master says whether or not the koan has the Buddha nature.
    2. If the round is a Mundo round, all of the students vote simultaneously on whether or not they think the koan has the Buddha nature. Voting can be done by counting to three and each student simultaneously holding up one or two fingers; one saying it has the Buddha nature and two saying it does not. The Master then reveals whether the koan has the Buddha nature and Students who guessed right all get a guessing stone.
  • At the end of a round, a student may use one of their guessing stones to guess the secret rule. The Master must then either supply an example koan which has the Buddha nature but does not satisfy the guessed rule, or else a koan which satisfies the secret rule but does not have the Buddha nature. If no such example exists, then the guessed rule must be equivalent to the secret rule and the game ends. The student who guessed correctly now becomes the Master.