Kickstarter edition shipped last week, and mine arrived on Monday, in time to prep for Tuesday's Game Night.
Hanabi is generally a well received game in my circles, so I introduced the group to Zendo. We played a couple rounds, using white and black pyramids for grading and Kickstarter green pyramids for guessing.
I started people off gently with a simple "must contain a large pyramid." That went well, maybe a bit too fast at two full goes around the table. Someone else volunteered to be a Zen master. I warned them not to get too clever as rules get harder quite quickly. In retrospect, I kind of figured out his rule ('even number of pips') a bit too fast because it's one a friend of mine uses as a teaching rule.
A third player volunteered to be Zen Master and, based on how quickly the last one was solved, decided to overcorrect. His rule, "more large blue pyramids than large reds" was quite hard, and we started running out of pyramids and marking stones. One online reviewer marks "more blue than any other pyramid" as a 3 out of 9, so this was at least a doubling of difficulty. Compounding the difficulty was that I only own PA, so we were limited to 5 trios of the four colors, and tearing old koans down.
I'm curious how more experienced Zendo players would rate that last rule, as it felt like a five or higher.
I <3 game systems: Cards, Dominoes, Piecepack, Pyramids, Decktet, Chesskers, Bead Games, etc.
Save MonopolyMan for last, his fight takes forever!
TLR Sounds pretty hard - but I'm a noob.
I've never actually played Zendo, but I am familiar enough with it to get the idea. So take that into consideration with my thoughts.
I'd say that last rule was more than twice as difficult as the "more blues" rule. Three or even 4 times more difficult.
First, You've got to break down the rule.
There are 5 components to this rule.
More (than) = 1
Large (first one) = 2
Blue = 3
Large (second one) = 4
Red = 5
Compare that to the sample 3 out of 9 rule.
More (than) = 1
Blue = 2
Each factor doesn't add to the complexity - it multiples or even exponentially increases the complexity.
The rule from your last player requires the isolation of two types of pieces, each type has two features... Not to mention having to figure out the relationship between them.
I can't say where I would put that on a "Blank out of 9" scale (having seen only one sample point, I have no sense of scale or ratio to work with) but it would be far higher than the example you gave.
I could see that taking a lot of time to work out.
Brighton and Hove
I'm an experienced Zendo player (I've lost count over the last decade how many games), and I'd consider that rule to be awkward as well as hard.
Especially with [only] 5 trios, any rule that requires a specific piece will have the problem of very quickly running out of that piece. In this case to actually have a koan that invokes the entirety of the rule (and not just "AKHTBN iff it contains at least one large blue", which I'd probably guess early, and is a fairly simple rule) requires at least 2 of a piece which you only have five of. I've run less restrictive versions of the same style of rule, eg "AKHTBN iff it contains more blue than red pieces", but try not to require pieces which are very limited in quantity because they run out. Specifying two particular pieces makes this hard for both working out what they are, and then building enough examples to work out the rule.
There is another factor that determines how easy or hard a rule is, which is counter examples. The master can be building counter examples which either lead players to the solution... or not. A passable example is limiting the number of either white or black marked koans to very few. I played a game not two days ago where I made a very simple rule pass around 17 turns (a reasonable length game for us) by only making black marked counter examples for the first 15 of those turns. So we had ~25 koans on the table, 20 were marked black. The moment I caved and started making helpful counter examples, they got it very quickly.