🎱Gollum's Lair: the cursed coins

Today's riddle falls into the "mechanical trials and tricks" category, this means that you can use them in your RPG sessions by recreating the situation described and inviting the players to have their PCs solve the riddle.

You will find later the solution to the enigma of last week.
The quickest to solve it was Fulvio Nicolamaria, who also added interesting details. Well done!

Go now and discover this week's riddle and then comment, write o contact me to give your solution!

Riddles in literature

Knight and Knaves is a very specific typology of puzzles which provides for the existence of two categories of characters, i Knights (knights) and i Knaves (infantrymen or villains). When a riddle of type Knight and Knaves one is always described situation in which i Knight are the ones who always say the truth and Knaves those that they lie always. Depending on peculiar situation where the solver is located, the puzzle has a always different solution.

The phrase Knight and Knaves it was minted in 1978 da Raymond Smullyan when he published the book that made him famous, entitled: "What Is the Name of This Book?". The book is a collection of over 200 puzzles, riddles and reasoning challenges that delve into paradoxes of logic and go to touch mathematical theories and even philosophical disciplines.

Gollum's Lair: the cursed coins — A portrait of Raymon Smullyan

Raymond Smullyan was a professor of philosophy al Lehman College and CUNY Graduate Center, in New York and also taught at theIndiana University.
In addition to a philosopher, Smullyan was astronomer, mathematical, magician and even an excellent one pianist.
Yes is off on February 6, 2017 at the ripe old age of almost 98 years but most likely it didn't affect him that much, after all it was he who said: "Why should I worry about dying?" He will never happen to me in my life! ».

It is said of him that one day he entered in the classroom and showed the students a coin that he had in his fingers. He told the students, "Either I have a coin in my fingers or 2 plus 2 is 5." It was obvious to everyone that, since he was holding a coin, he had said the truth. But suddenly, with a sleight of hand, he did to disappear the coin.

The audience immediately understood it joke of which he had been a victim. Showing the coin between his fingers, Smullyan had proved the truth of your claim based on the first alternative. But when the coin was disappeared, the first alternative had fallen and the truth of the statement now had to rest upon second alternative: therefore, Smullyan had proved that 2 plus 2 is 5.

The puzzles of the type Knight and Knaves have numerous implications in paradox theories related to epistemic logic including Fitch’s paradox of knowability. This is not the place to go into philosophical dissertations, we prefer to return immediately to our riddles.

one of the examples most famous of the use of the typology Knights and Knaves it's right in the movie Labirinth, which we talked about in last week's article. The most interesting of the puzzles of this type is undoubtedly the one that was published in 1996 da The Harvard Review of Philosophy and before that, in Italy, from The Republic in 1992 with the title of "The hardest riddle in the world". The text reads like this:

Three divine oracles are called Truthful, Mendaceous and Unpredictable.
True always tells the truth, Mendace always tells the false while Unpredictable decides whether to be sincere or not in a completely casual way.
The objective of the game is to determine the respective identities of the oracles by asking them three questions that can be answered with a "yes" or a "no".
Each question must be posed to only one of the oracles, who, while understanding the español, will always answer in their own language with the words "da" or "ja". It is not known which of these terms corresponds to "yes" and which to "no".

It is all too easy to go looking for the solution of "The hardest riddle in the world" sifting through the web, we invite you to look for a solution yourself. Always if you think you can do it yourself ...

Puzzle categories

For convenience I have divided the riddles into three categories and every week I will indicate to you which of these categories belongs the riddle that I propose to you:

Textual riddles

In this category you will find more riddles classical, those that can be proposed by an enemy orally or that the characters can find writings on a door, on an ancient table, on a tombstone and so on. Normally the solution one is represented password or from one phrase.

Mathematical puzzles

The puzzles based on numerical calculations e mathematical operations. To fix them, most of the time, you will need to set up and fix an equation or a system of equations. Some of them can be solved by doing calculations in mind, but the difficulty increases if you don't have pen and paper.

Encrypted and encrypted codes

It is testi e passwords hidden in other texts by means of encrypted keys or gimmicks that require a intuitive approach to find a complete meaning to a seemingly meaningless set of letters and numbers and to succeed in read between the lines".

Mechanical tests and pitfalls

Puzzles of this particular type can be inserted into an adventure by tying them tightly to objects that the master can have the PCs or situations they can run into. During the game, it will not be necessary to read the riddle text but simply describe the situation, far find objects and provide the characters with a strong motivation to solve the problem.

The solution to last week's riddle

The text of the riddle can be found here.

Solution: Nobody knocks on the door of what they think is their room. There is something wrong, just enough to worry the woman who comes out for help.

This week's riddle

THE CURSED COINS

Category: mechanical tests and pitfalls

difficulty: difficult

Text:

After defeating the keeper of a dungeon, the PCs find the much coveted treasure. There are in front of them ten chests each filled with thousands of gold coins. The heroes however had previously been warned that the coins contained in one of those chests are false. As if that weren't enough, it's all about money accursed: taking them out of the dungeon would bring unimaginable misfortunes to those who dared to do so.

In a corner of the room there is one balance with related weights. The scale can give us a value extremely accurate of the weight placed on it.

Knowing that a cursed coin weighs exactly one gram less of a authentic, and that a genuine coin weighs exactly 10 grams, how they can locate the treasure chest of cursed coins using the scales once?