What are the Riddle Rules?

Question

In J. R. R. Tolkien's The Hobbit, while Bilbo is in the cave and has the ring, he and Gollum end up asking each other riddles. After the exchange, Gollum or Bilbo mentions some riddle rules. These rules, as far as I can remember, are not previously brought up in the book.

What was the name of the riddle rules referenced and, if they're available, what are the rules?

Answer 1

We don't really know, as they're not mentioned.

We don't know all of the rules, because they're never really mentioned - this is the only time AFAIK, and they don't really say much:

"Both wrong," cried Bilbo very much relieved; and he jumped at once to his feet, put his back to the wall, and held out his little sword. He knew, of course, that the riddle-game was sacred and of immense antiquity, and even wicked creatures were afraid to cheat when they played it. But he felt he could not trust this slimy thing to keep any promise at a pinch. Any excuse would do for him to slide out of it. And after all that last question had not been a genuine riddle according to the ancient laws.
_{The Hobbit, chapter 5}

However, we can take a guess as to what the one that he broke here is:

Each riddle must have a clearly correct answer.

Bilbo's question wasn't a riddle, as it could have lots of answers, and cannot be proved. (This is actually sort of like what we do on Puzzling - riddles that don't have an answer that can be proved to fit all of the lines are closed.)

Answer 2

In addition to Mithrandir's answer, I think that the more significant rule Bilbo broke was that his "riddle" was more of a question whose answer could not be deduced. In essence, the rule is that the answer to the riddle that is asked must be able to be deduced from the actual riddle itself. In Bilbo's case, the answer to his riddle of "what's in my pocket?" is based on simply pure luck, and thus, the answer can't be deduced from the riddle.

Answer 3

It's worth noting that Tolkien based all of his riddles in style, and some of them in actual wording, on classical "old literary" riddles. As mentioned in the answer to Who wrote Tolkien's riddles?:

As for the Riddles: they are 'all my own work' except for 'Thirty White Horses' which is traditional, and 'No-legs'. The remainder, though their style and method is that of old literary (but not 'folk-lore') riddles, have no models as far as I am aware, save only the egg-riddle which is a reduction to a couplet (my own) of a longer literary riddle which appears in some 'Nursery Rhyme' books, notably American ones.

_{-- Tolkien's Letters, Letter #110}

So the theme is very much that of old, classical riddles, and thus it seems unlikely that there was any hard-and-fast ruleset as such. In ancient times people were generally less concerned with restricting themselves with multiple rules (we can see this also in the use of language, e.g. the way there were no standard English spelling rules until several hundred years ago, but I digress). To make the game fair and fun, it was enough for the riddle to be uniquely solvable - i.e. there's a solution which is deducible from the riddle as stated and which is the only word fitting it.

These are basically the same criteria as described by Mithrandir, fi12, and TML in their answers, but I can back them up as 'the' criteria for a solid classical riddle with citations from some of the internet's top experts on riddling, namely those at Puzzling SE:

• a "solid" Riddle should have one and only one interpretation which coherently addresses each line/clue contained in the Riddle.

• However hard the riddle a supermajority of fluent English (or whatever your target language may be) speakers must, when presented with the solution, consider it the only correct one.

• The idea is to use as many different figurative or metaphoric descriptions as are necessary to ensure that the intersection of their interpretations is a single word or phrase.

The idea is always the same. Stylistic additions such as rhyme, rhythm, twists of meaning, and even metaphor are optional. The only real rule - insofar as there are any "rules" at all - is that the riddle should be uniquely solvable from the information provided, i.e. from the statement of the riddle itself. (And if they aren't, they'll be closed on Puzzling :-) )

Answer 4

Wikipedia has a somewhat decent account of riddles as a game. While the riddles in The Hobbit are generally considered reflective of those found in The Exeter Book, that book does not define any system of "rules."

Answer 5

I think it's important to note that one of the most important "Rules" must be "the asker must propose the riddle and it must be accepted by the askee". This is the only reason Bilbo's "riddle" worked, as it was not a traditional riddle and would otherwise be considered cheating. Though there could be many answers, Gollum accepted the riddle by stating that he must be given three guesses, which Bilbo accepted.