|Age range||All ages|
|Setup time||< 5 minutes|
|Playing time||5–30 minutes|
|Skill(s) required||Inductive reasoning
Within Zendo, most players are known as Students. Students will build structures, known as koans. Before play, one player (known as the Master) will invent a Rule. After each Student's turn, the Master will determine whether that Student's koan follows or breaks the Rule (also stylized as: "possesses or lacks the Buddha-nature", in fitting with the game's philosophical theme). Students will take turns building koans. After each koan is completed, a student may choose one of two options:
- Ask the Master whether the koan has the Buddha-nature, or:
- Attempt to guess the Rule.
Students may choose only one option. The first student to correctly state the rule wins that round and becomes the new Master. There are no losers.
To play Zendo, some set of colorful playing pieces are required. Origami pyramids are a common piece, since they are quick and easy for one person to make.
The rules were published in 2001 after more than a year of playtests and changes. A boxed set of the game was released by Looney Labs at the 2003 Origins Game Fair but is now out of print. The set contained 60 Icehouse pieces in red, yellow, green, and blue, 60 glass stones and a small deck of cards containing simple rules for beginners. 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.
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.
Philosophy of play
Although it is possible to 'win' Zendo by correctly stating a rule, there are no losers. Every player benefits from observing and following play. Furthermore, Masters may 'win' as well, by choosing a challenging, yet simple Rule.
Pieces tend to be objects with multiple discrete distinguishing attributes; for example, dozens of Icehouse pieces, or (open-bottomed) origami pyramids of different sizes and colors. Using these, it is possible to create many different parts inside a koan. A partial list of koan attributes is below.
- Size of pieces
- Color of pieces
- Number of pieces
- Relative orientation ("pointing at another piece/parallel to another piece") of pieces
- Groundedness (pieces supported entirely by other pieces are not "grounded") of pieces
- Zendo won the 2003 Origins Award for "Abstract Board Game".
- Zendo was named one of the 2005 Mensa Select games by American Mensa.
- "Game Review: Zendo". Critical Hits. 16 Nov 2005. Retrieved 9 Sep 2015.
- Petty, Mike (3 Jul 2015). "The Fun and Beauty of Game Design: An Interview with Kory Heath.". Fair Play Games. Retrieved 9 Sep 2015.
- "fogus: Games of Interest: Zendo". Snapbuzz.org. Retrieved 9 Sep 2015.
- Heath, Kory (8 September 2004). "Zendo—Design History". Retrieved 2010-02-23.
- "Origins Award Winners for 2003". ICv2. June 28, 2004. Retrieved June 8, 2015.
- Arneson, Erik. "Mensa Select Award Winners". About.com. Retrieved June 12, 2015.