History Main / KnightsAndKnaves

* Also subverted in an episode of ''WesternAnimation/SamuraiJack''. A two-headed creature poses this riddle to Jack, claiming that one of his heads is magic, and if he chooses to be swallowed by it, he will be granted a wish, while if he is swallowed by the other head he will simply be eaten. One head always lies, and the other always tells the truth. Jack solves the riddle using the "If I asked the other one which was correct..." solution, [[spoiler:but it turns out that it was all just a trick by the creature to get idiots to willingly feed themselves to it. [[SnapBack We're not shown how Jack escaped this situation]], but given Jack is [[JustEatHim still alive when he arrives in their stomach]], he probably cut his way out]].

* ''Series/MastersOfTheAir'': During the flight from England on their way to bomb Regensburg, Blakely (the pilot) quizzes his crew with the riddle to pass the time during the mission, rejecting all of their suggested answers as incorrect. After the mission goes disastrously for their bomb group, Blakely brings up the riddle again while asking Crosby (the navigator) which way they should fly while seeking out safety at a distant airfield in Algeria. If Crosby gives the right answer, they make it to safety. The wrong answer, they risk crashing in the North African desert. After Crosby is proven correct, he finally presses Blakely about the riddle:

--->'''Blakely''': [[spoiler: [[SubvertedTrope I was hoping you'd tell me.]]]]

* Subverted in the MiniSeries ''Series/The10thKingdom'', where the main protagonist Virginia and her father Tony have come from our world to the land where the classic fairytales took place. Two doors to safety or death are guarded by a talking frog who offers one question, but claims to always lie (which would make it unsolvable as a logic problem since the rules themselves are in doubt). By now Tony has had it with this kind of problem.

* Subverted in the MiniSeries ''Series/The10thKingdom''. Two doors to safety or death are guarded by a talking frog who offers one question, but claims to always lie (which would make it unsolvable as a logic problem since the rules themselves are in doubt). By now the father of the protagonist Virginia has had it with this kind of puzzle.

* One of the most difficult variants is [[https://en.wikipedia.org/wiki/The_Hardest_Logic_Puzzle_Ever The Hardest Logic Puzzle in the World]] by George Boolos, which is of course directly taken from RaymondSmullyan's work.
-->Three gods A, B, and C are called, in no particular order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a completely random matter. Your task is to determine the identities of A, B, and C by asking three yes-no questions; each question must be put to exactly one god. The gods understand English, but will answer all questions in their own language, in which the words for yes and no are da and ja, in some order. You do not know which word means which.

* ''Film/{{Labyrinth}}'': The LicensedGame for the UsefulNotes/Commodore64 includes the scene as described in the Film folder; but as the engine was too limited to let you ask specific questions, the solution is different. The player must open each door and see which path has the sign saying "[[NeonSignHideout To the Castle]]" and which says "[[ThisWayToCertainDeath To Certain Death]]." The real danger is assuming that [[OutGambitted something so obvious must be a trick]] and falling to your doom.

* Subverted in ''Anime/YuGiOh'' During the Duelist Kingdom arc, the Meikyu Brothers confront Yugi and Jounouchi/Joey with this puzzle. Jounouchi thinks he's solved the riddle, seeing that he's heard it before, but Yugi correctly guesses that the brothers' description of the puzzle is in fact part of it, and that ''both'' the brothers are lying about the whole puzzle (they both say that one ''always'' lies and one ''always'' tells the truth, which is impossible because someone who ''always'' lies would be unable to give an honest description of the puzzle, and thus could ''never'' agree with someone who always tells the truth), and outwits them his own way. They're cheaters, anyway. Whenever a person asks his question and chooses a door, they always claim the opposite door is the right one. Yugi [[BeatThemAtTheirOwnGame tricks them]] by making them think he's choosing one door via ExactWords, waiting for their answer, and revealing he chose the other one. [[spoiler:[[ShaggyDogStory Both doors lead to the exact same place anyway]]]].

* The ''AudioPlay/BigFinishDoctorWho'' audio drama ''The Pyramid of Sutekh'', a sequel to "Pyramids of Mars", above, also features the puzzle. Franchise/BerniceSummerfield was not impressed, first saying "Oh, good! Robot mummies who've read ''Literature/AliceInWonderland''", then "Oh, please! Is there anyone who ''doesn't'' know this yet? As an archaeologist of repute, I'm insulted that I'm even expected to play along with this!" An outside force then [[CuttingTheKnot blew a hole in the wall]], saving her from having to deal with the "cliché of Horus". While the actual puzzle is avoided, one of the robots takes to following her around trying to understand things and help. At least, that's what it ''says''. It turns out [[spoiler:to be the lying guardian, something Benny only realises after she's become desperate enough to take its advice at face value. When she discovers she's done exactly the wrong thing, the robot tells her "I am ... not sorry."]]

* Attempted on ''[[https://https://www.youtube.com/shorts/q4aUU9u2CvE Game Changer]]'' until the guards confuse themselves. They give the hero a river-crossing puzzle to pass the time while they try to sort it out amongst themselves.

* ''TabletopGame/PerplexCity'' has a version with seven speakers, at least three of whom are knights and three of whom are knaves.

* ''Literature/{{Hilda}}'': Hilda faces a riddle like this in ''Hilda and the Hidden People'', with two water spirits as the liar and truth-teller respectively. She has to figure out which of two caves is the one the Elf Prime Minister resides in, with the other supposedly housing a flesh-eating troll, by asking the two water spirits only a single question.

* A variation in one of the junior ''TabletopGame/{{Clue}}'' books, where one of [[AbsentMindedProfessor Professor Plum]]'s inventions causes [[GrandeDame Mrs. Peacock]] to [[CloningBlues get cloned]]. The catch is that her clones are aware they're clones, violently homicidal (well, moreso than usual), and uncontrollable liars, but none of the other guests nor Mr. Boddy himself realize this until the last page. They keep asking "Which of you is the real Mrs. Peacock?", which only leads to the inevitable answer of "I am!" from all of the Peacocks present. The book asks the reader to supply the answer to find the real (presumably truth-telling) Mrs. Peacock--the solution being simply to ask a purely factual question such as "What is two plus two?" and presumably dispose of the clones who started spouting mathematical nonsense.

* Played straight in the ''ComicBook/SonicTheHedgehogArchie In Your Face'' special; the Freedom Fighters are faced with a giant, two-headed dragon who offers this sort of riddle. Sally does the standard, "Ask one head what the other will say" answer, which works.

* ''Film/{{Labyrinth}}'': The LicensedGame for the Commodore 64 includes the scene as described in the Film folder; but as the engine was too limited to let you ask specific questions, the solution is different. The player must open each door and see which path has the sign saying "[[NeonSignHideout To the Castle]]" and which says "[[ThisWayToCertainDeath To Certain Death]]." The real danger is assuming that [[OutGambitted something so obvious must be a trick]] and falling to your doom.

* In Episode 327 of ''Webcomic/TheOrderOfTheStick'', this is the [[http://www.giantitp.com/comics/oots0327.html Test of the Mind]] the Order goes through to get to the Oracle of Sunken Valley (which prompts Roy to remark "that's the last nail in the coffin for the hope that these Tests would be even remotely original"). Haley solves it by [[CuttingTheKnot shooting one of the guards]], then noting that the guard she shot is screaming "you shot me!" while the other guard insists "she totally didn't shoot you". The next time Haley passes through, the guards remember her and hastily direct her to the correct path before she can do anything. Haley doesn't understand why, because the Oracle's [[LaserGuidedAmnesia memory charm]] means nobody remembers anything that happens in the valley ''except'' for the answer he gives them.