History ChekhovsClassroom / Literature

* Hermione does this in nearly every ''Literature/HarryPotter'' book (especially the seventh), because she was the only one paying attention in class when the relevant magic was discussed. Also used when Harry gave Ron the bezoar after he drank the poisoned mead given to them by Professor Slughorn.
** This sort of thing is even done across ''books''. In the fourth book, Dumbledore casually mentions a room filled with chamber pots that he found when he desperately needed a bathroom, and then was unable to ever find again. In book 5, the room is formally introduced as the Room of Requirement, and ends up being an integral part of the story in every remaining book in the series.
** And in the very first book, Snape quizzes Harry, and one of the questions is about bezoars. In book six, it's used to save Ron's life, although Harry re-learns about it from Snape in a roundabout way.
** [[RunningGag "Has]] ''[[RunningGag no-one]]'' read [[{{Doorstopper}} "Hogwarts: A History"]]?
** Divination class is very much a Chekhov's Classroom. Most of the class believes that it's ridiculous fakery, but looking at the predictions made with knowledge of how the books turn out reveals a surprising amount of {{Foreshadowing}}.

* Modern pulp author Creator/MatthewReilly uses this to a ''ridiculous'' degree. Two examples:
** In ''Literature/TempleMatthewReilly'', there's a throwaway sentence from the protagonist about how he'll need to change his PIN after reading a story in the paper about how most people use their birth dates as pass codes. Guess how he defuses the superweapon his brother worked on? Guess again, it wasn't his birthday. But that example was used as a starting point. [[spoiler:His brother always used Elvis' army serial number as his PIN. The Nazi scientist used his supposed date of execution.]]
** In ''Literature/Area7'', a precocious youth found in the middle of a government base delivers a buttload of the kind of trivia kids that age accumulate and share at any opportunity, including how komodo dragons are sensitive to changes in the Earth's magnetic field. So there's a scene where the main character has to fight off ''komodo dragons'' in a watery pit with his magnetic grappling hook.
* Subverted and lampshaded in ''Literature/TheHitchhikersGuideToTheGalaxy1''.
-->'''Arthur:''' You know, it's at times like this, when I'm trapped in a Vogon airlock with a man from Betelgeuse and about to die of asphyxiation in deep space, that I really wish I'd listened to what my mother told me when I was young.\\
'''Ford:''' Why, what did she tell you?\\
'''Arthur:''' I don't know, I didn't listen.
* ''Literature/{{Knightmare}}''
** In the Stranger Matter book, the protagonist remembers a comic his friend told him about in where crossbow being the only weapon to pierce the bad guy's armor. He later uses a crossbow to pierce the evil knight's armor and kill him.

* In one of the Literature/AmericanGirl solve-it-yourself mystery books, Molly and her English houseguest Emily discuss [[SeparatedByACommonLanguage the differences between American and British English]], including how the word "queue" (pronounced the same way as "cue") means "line" in England. Later Emily ends up performing awkwardly in a school show and ends up about ready to cry when the teacher scolds her; Molly jumps in and explains that when the teacher told Emily to wait for her cue to go on stage, Emily looked for a line that didn't exist and as such, her performance got thrown off.
* In ''Literature/{{Shatterbelt}}'', Mr. Bailey teaches Tracy a bit about geomorphology, showing her a map of South Australia with the fault lines marked in. "There are lots of faults near Adelaide. A whole string of them. A shatterbelt." Thus foreshadowing [[spoiler:the earthquake that's about to hit their town.]]
* In ''Literature/PrincessAcademy'', several of the lessons the girls (especially Miri) learn end up becoming important.
** After learning about economics, Miri realizes that the traders who buy from their village have been ripping them off for years, and helps them to negotiate better deals.
** Another lesson they're taught is a set of rules for diplomacy and negotiation. When they get into a massive fight with their teacher, Miri has the idea that they can use those strategies to negotiate a more favorable arrangement. The teacher is so impressed by their handling of the situation that she accepts their offer on the spot.

* A downplayed example in ''Literature/ColdDays'': Harry is stated to have used the cue "Fuego" for his fire spell because of the Spanish lesson he took that day.
* Played with in ''Literature/{{Animorphs}}'': Ax, being the TokenNonHuman, is often their only source of information on alien species, technology, or physics, but half the time he wasn't paying attention in class on the day that subject was taught. Since none of the other Animorphs know ''anything'' about aliens to begin with, it's still better than nothing.
* In ''[[Literature/Eclipse2007 Eclipse]]'', Jacob's family tells a story about how a woman helped distract a vampire by cutting herself, which Bella does in the final battle. Also, Jasper warns everyone not to let a vampire grab you under any circumstances. [[spoiler: Jacob forgets this and is nearly broken in half with a BearHug]].

* Hermione does this in pretty much every ''Literature/HarryPotter'' book (especially the seventh), because she was the only one paying attention in class when the relevant magic was discussed. Also used when Harry gave Ron the bezoar after he drank the poisoned mead given to them by Professor Slughorn.

* In the Strange Matter book ''Literature/{{Knightmare}}'', the protagonist remembers a comic his friend told him about in where crossbow being the only weapon to pierce the bad guy's armor. He later uses a crossbow to pierce the evil knight's armor and kill him.

** In ''Literature/{{Temple|MatthewReilly}}'', there's a throwaway sentence from the protagonist about how he'll need to change his PIN after reading a story in the paper about how most people use their birth dates as pass codes. Guess how he defuses the superweapon his brother worked on? Guess again, it wasn't his birthday. But that example was used as a starting point. [[spoiler:His brother always used Elvis' army serial number as his PIN. The Nazi scientist used his supposed date of execution.]]

** In ''Literature/{{Temple}}'', there's a throwaway sentence from the protagonist about how he'll need to change his PIN after reading a story in the paper about how most people use their birth dates as pass codes. Guess how he defuses the superweapon his brother worked on? Guess again, it wasn't his birthday. But that example was used as a starting point. [[spoiler:His brother always used Elvis' army serial number as his PIN. The Nazi scientist used his supposed date of execution.]]

** In ''Literature/{{Temple}}'', there's a throwaway sentence from the protagonist about how he'll need to change his PIN after reading a story in the paper about how most people use their birth dates as pass codes. Guess how he defuses the superweapon his brother worked on? Guess again, it wasn't his birthday. But that example was used as a starting point. [[spoiler:His brother always used Elvis' army serial number as his PIN. The {{Nazi}} scientist used his supposed date of execution.]]

* Hermione constantly saves the day in ''Literature/HarryPotter'' because she was the only one paying attention in class when the relevant magic was discussed.

* Hermione does this in pretty much every ''Literature/HarryPotter'' book. Especially the seventh. Also used when Harry gave Ron the bezoar after he drank the poisoned mead given to them by Professor Slughorn.

** In ''Literature/{{Temple}}'', there's a throwaway sentence from the protagonist about how he'll need to change his PIN number after reading a story in the paper about how most people use their birth dates as pass codes. Guess how he defuses the superweapon his brother worked on? Guess again, it wasn't his birthday. But that example was used as a starting point. [[spoiler:His brother always used Elvis' army serial number as his PIN. The {{Nazi}} scientist used his supposed date of execution.]]

-->'''Arthur:''' You know, it's times like this I wish I'd listened to my mother.\\
'''Ford:''' Why, what did she say?\\
'''Arthur:''' I don't know, I wasn't listening!

* Modern pulp author MatthewReilly uses this to a ''ridiculous'' degree. Two examples:

** In ''{{Temple}}'', there's a throwaway sentence from the protagonist about how he'll need to change his PIN number after reading a story in the paper about how most people use their birth dates as pass codes. Guess how he defuses the superweapon his brother worked on?
*** Guess again, it wasn't his birthday. But that example was used as a starting point. [[spoiler:His brother always used Elvis' army serial number as his PIN. The {{Nazi}} scientist used his supposed date of execution.]]
** In ''{{Area 7}}'', a precocious youth found in the middle of a government base delivers a buttload of the kind of trivia kids that age accumulate and share at any opportunity, including how komodo dragons are sensitive to changes in the Earth's magnetic field. So there's a scene where the main character has to fight off ''komodo dragons'' in a watery pit with his magnetic grappling hook.

-->'''Arthur''': You know, it's times like this I wish I'd listened to my mother.\\
'''Ford''': Why, what did she say?\\
'''Arthur''': I don't know, I wasn't listening!

* In DanBrown's ''AngelsAndDemons'', an early discussion of how well an ImprovisedParachute can work saves Robert Langdon's life when he jumps from an exploded helicopter with a window cover. This is also lampshaded at the time the discussion takes place.

-->Arthur: You know, it's times like this I wish I'd listened to my mother.
-->Ford: Why, what did she say?
-->Arthur: I don't know, I wasn't listening!

* In the Strange Matter book 'Knightmare', the protagonist remembers a comic his friend told him about in where crossbow being the only weapon to pierce the bad guy's armor. He later uses a crossbow to evil the pierce the evil knight's armor and kill him.

*** And in the very first book, Snape quizzes Harry, and one of the questions is about bezoars. In book six, it's used to save Ron's life, although Harry re-learns about it from Snape in a roundabout way.

* In DanBrown's ''AngelsAndDemons'', an early discussion of how much a small flat object can slow down a falling person saves Robert Langdon's life when he uses a window cover to slow his fall from an exploded helicopter. This is also lampshaded at the time the discussion takes place.

* Subverted and lampshaded in ''TheHitchhikersGuideToTheGalaxy''.