Zendo is a game of inductive logic designed by Kory Heath in which one player (the "Master") creates a rule for structures ("koans") to follow, and the other players (the "Students") try to discover it by building and studying various koans which follow or break the rule. The first student to correctly state the rule wins. Zendo can be compared to the card game Eleusis and the chess variant Penultima in which players attempt to discover inductively a secret rule thought of by one or more players (called "God" or "Nature" in Eleusis and "Spectators" in Penultima) who declare plays legal or illegal on the basis of their rules. It can also be compared to Petals Around the Rose, a similar inductive reasoning puzzle where the "secret rule" is always the same. The game can be played with any set of colorful playing pieces, and has been sold with a set of 60 Icehouse pyramids in red, yellow, green, and blue, 60 glass stones and a small deck of cards containing simple rules for beginners. The Icehouse pieces were replaced in the second edition with blocks, single size pyramids and wedges. Origami pyramids are a common choice of playing piece. History The rules were published in 2001 after more than a year of playtests and changes. In 2004, the Zendo boxed set won Best Abstract Board Game of 2003 at the Origins Awards. In 2005, the set won the Mensa Select Game Award. Zendo is also published in Looney Labs' Playing with Pyramids, a book of rules and strategies for a dozen popular games playable with Icehouse pieces. In December 2017, the company reissued Zendo game separate from the Looney pyramids line for the first time. The Icehouse pyramids were replaced by blocks, single size pyramids and wedges. Buddhist terminology were also removed from the instructions. In August 2018, Zendo Rules Expansion #1 was released, adding 10 rule cards to the game. Gameplay Within Zendo, most players are known as Students, who will build structures of pieces known as koans. Before play, one player (known as the Master) will invent a secret Rule, such as "a koan has the Buddha-nature if and only if it contains one or more green pieces". The Master then builds two koans - one which follows the rule and one which does not. These are marked with a white and black stone respectively. Students then