Just about every minor object, detail, and character introduced early in the story becomes significant later on, more often than is healthy for the reader's mind. Almost everything explicitly discussed in dialogue returns later in the saga — or even in a completely separate saga — to turn the plot around.
Chekov's Gun
- In Red and Blue arc, it was mentioned in the very first chapter that Blue just got back from studying overseas. It's revealed in the GSC arc that the one training him was Chuck.
- One of the first item-instances include a Moon Stone that Red obtained in the early chapters. It would come into play when it's used to evolve Green's Clefairy into Clefable in the Silph Co. HQ.
- Koga's Arbok gets cut in half. It turns out in the next arc that it was able to grow its limbs back, which helps against Agatha. Its dismembered tail also comes into play, serving as a decoy against her Gengar.
- Lt. Surge's lightning-proof gloves was something that Red happened to take along with his Thunder Badge, but it allowed Red to defeat Giovanni near the end of the arc by supercharging Pika while still inside the ball.
- Another thing that was implied was that Pika can recognize trainers by their smell, as with Green disguised as Sabrina. Both of these are then used against it by Super Nerd Miles, who managed to create a suit that has the same insulating properties and mimics Red's scent from scraps of Red's glove he found.
- The two feathers adorning Yellow’s hat (given by Green) seem like a cool decoration…until it turns out to have been the Rainbow Wing and Silver Wing that’s required to access the warped space within time.
- What makes it even better is how Yellow used the power previously when freeing the Legendary Beasts from the Burned Tower.
- In the same arc, Green’s Blastoise is shown to have a limited supply of water for propulsion. In the GSC arc, Sabrina tells Red that the spring on Mt. Silver contains flammable gas, with Morty later observing that Entei’s flame can melt the Masked Man’s ice.
- Combine all of this together, and it turns out that Red filled Blastoise with Mt. Silver spring, which allows them to spread Entei’s flame throughout the forest and free the crew from Pryce’s ice.
- In her battle against Lance, Yellow's arm is injured by a bubble beam, requiring a cast from her Caterpie. This cast is untangled in the final battle, where the Kanto trio are able to send their Pokémon's energy through the string to aid her.
- Gold was seen listening to a song about a Lapras in the first chapter of the arc. In the final chapter, the song is revealed to have been made by Professor Oak and his friends to cheer Pryce up on the loss of his Lapras.
- Gold learns Silver's name through his glove he took from him (like how Red learned of Green's name), as Silver wrote his name there. In the FRLG arc, it turns out to have been because Giovanni initialed his belongings due to Silver's habit of losing things.
- The final one in the arc comes in the form of a Pokégear that Erika gives to Red just in case. While it doesn't contribute to the final battle, it sets up the awkward love triangle scene when Misty decides to call Erika.
- Mr. Briney shows Ruby a drawing of an ancient fish Pokémon that can dive to the unreachable depths, which Ruby just passed it up as ugly. Later, Ruby sees Sapphire with that very same Pokémon, Relicanth, where what he learned from Mr. Briney allows them to use it to reach the Seafloor Cavern.
- One would hardly think much of Courtney's bubble gum-chewing habits...except that she would later use it to send her memory firelighter to Ruby when trapped in the Cave of Origin.
- 2 things return from Mauville City. First is the New Mauville, which the underground city becomes handy in evacuating the citizens of Hoenn when Groudon and Kyogre clash. Second one is a generator that can absorb and release electricity from Electric-type Pokémon, which the Trick Master repurposes it to be airborne. By combining its power with Plusle and Minum, Sapphire and Wallace are able to break through the barrier surrounding Sootopolis City.
- Sapphire picks up a shard of the Grand Meteor after Team Aqua admins made their escape in Mt. Chimney, which ends up serving as a lynchpin in removing the Red and Blue Orb from Team Magma and Aqua leaders.
- Another item Sapphire had was a letter from Mr. Stone to Steven. Turns out it held the final clue in unsealing the Legendary titans.
- When Ruby first meets Wallace, he's so fixated on him that he doesn't notice his Mumu's cue on a cigarette fire, and leaves his Feebas out when challenging Wallace. This is later used by Wallace as evidence that he's selfish and doesn't trust his Pokémon.
- Ruby tells Sapphire in Fortree City that he'll eventually be going back to Johto. This is what pushes Sapphire to make the confession to him before it's too late.
- Gold's fake Guile armor seemed to be a weird plan that went nowhere. However, Archie later mistakes it for his real set of armor, leading to his doom. Gold jumps on this as well.
- A minor example are Ball Capsule and stickers that the Solaceon News Press gives to Platinum. This comes into play when they're in Solaceon Ruins and are separated from their Fire Type Pokémon, where the special effect from the stickers serves as a source of light.
- Another thing that happened in Solaceon News Press was that they took photos of the Sinnoh Trio without permission, where the news would even reach Canalave City where Platinum's father is at. This is averted however as he and Prof. Rowan decline to check out the newspaper, leading them to miss the fact that Platinum's traveling with the wrong people.
- When Diamond steals Cyrus' camera on Celestic Town, Cyrus unearths an Iron Ball in the process of trying to get it back. The trio picks it up, where this item is then used against Fantina in her Gym Battle.
- Cynthia is given the ancient scripture by her grandma to decipher it. Good thing she accompanies the Sinnoh Trio to the Spear Pillar, as Platinum is able to decipher it and find a way to stop Cyrus’s control.
- Riley decides to keep the Galactic Drone that he and Dia shot down at Iron Island, which allows him to track down its true owner, Sird. In the following arc, it leads him, Platinum, and the others at Battle Frontier to the site of the final battle when it's repaired by Thorton.
- After the final battle at Sinjoh Ruins, Giratina opens a portal to the Distortion World to return, which then allowed Archie and Maxie to return to the real world.
- The very beginning of Black and White shows the starters fighting while Professor Juniper is talking on the phone, following with those same starters delivered to the protagonist. This is later used against her by N to support his claim of how they treat Pokémon like tools.
- Whitley briefly mentions that her hobbies include stargazing, which Blake remembers this and later gives her a telescope to get close to her.
- When first meeting X and co., Clemont mentions that anything caught on Aipom Arm's camera can be viewed from his glasses or camera. X finds his glasses in Lavarre City, which lets him know that he's at Geosenge Town.
- In the early chapters for ORAS arc, Steven reveals that Mega Evolution can only be maintained during Pokémon battles. Giovanni comes back to this fact to deduce that the meteor must have a Pokémon in it, that is, Deoxys.
- When Ruby first encounters the Draconid people, it's revealed that Dragon-type Pokémon leave vapor trails that can only be seen by the Draconids. Later in the Meteor Village, Ruby remembers this fact and asks the village elder where Rayquaza went, where she showed that she saw a trail of cloud heading to Johto.
- The Draconids also asked Ruby if Zinnia had a scroll with her, which he replied she did not. Ruby makes good use of this exchange by stealing a scroll from her when he meets her again in Sea Mauville.
- When Sun feels unworthy to deliver the berry to Tapu Bulu, Moon then decide to offer it with him as a promise to fight off the danger in Alola. This leads the guardian deities to choose the two to bond with Solgaleo and Lunala.
- After fusing with Nihilego, Lusamine mentions that the Ultra Beast is especially attracted to those with anxiety and worry. At the end of the arc, Faba is dragged off to Ultra Space by a horde of them due to panicking while corned by Sun’s Cent.
- When trying to stop Mother Beast Lusamine by shooting her Beast Ball, Moon is blinded by a light and misses. That ball is later found by Sun in Mount Lanakila and is used to capture Ultra Necrozma.
- Soudo and Sonia were treasure hunting in Turffield, with Sonia even telling Nessa that they've found something. It turns out to be an Expert Belt, which lets Soudo finish off Opal's Alcremie some time later.
- Throughout the arc, Henry and Casey travel in a trailer house driven by Professor Magnolia. This then comes handy during the Darkest Day, when most of the Gym Challengers and Gym Leaders are in Wyndon and are unable to use the monorail and the Flying Taxi.
- When there is an explosion in Hammerlocke, Raihan enters the Energy Plant through an access hatch. He later tries to use it to have him, Sonia, Leon, and Nessa enter the plant again, but it turns out to now be blocked off.
Chekhov's Army
- Even nameless characters would appear some chapters later as either an ally or a throwaway gag.
- The first, rather minor example is when the “good” gym leaders Red met, i.e. Brock, Misty, and Erika help take care of the Rocket grunts in Saffron City.
- The next example occurs in the GSC arc, where the Pokémon Fan Club chairman rallies all the minor characters that appeared throughout the first 3 arc to aid in the battle against the Masked Man.
- The crowning example is the BW arc, where all the minor characters Black met throughout the arc all show up to keep the Seven Sages at bay, in place of Gym Leaders doing it in Pokémon Black and White.
Chekhov's Boomerang
- And chances are, some characters may return unexpectedly or some items become relevant again.
- Lance turns out to be the guy instructing Silver, Ruby summons Celebi in the RS saga, "Guile Hideout" turns out to be Archie, and the whole Emerald saga was a ploy to change the previous chapter's protagonists back to normal from being petrified.
- On the object end of things, there’s the Grand Meteor taken to extremes. Not to mention the aforementioned shard, it turns out to have contained the lifeform that would later become Deoxys, and the meteor in ORAS arc turns out to have been the very same meteor but is now many times bigger.
- Green's Silph Scope was first used in Red and Blue arc and wouldn’t be used again until the ''FireRed and LeafGreen'' arc, with even Silver using one.
- Blaine's forced bond with Mewtwo would stay with him for long, which led to it being Mewtwo's Achilles' Heel in Yellow arc and his need to cure the condition led him bonding with Entei. Finally, in the XY arc it lets him use Mega Evolution twice with Mewtwo.
- Another thing returning in ''FireRed and LeafGreen'' arc also includes Giovanni's statue.
- Lorelei's Voodoo Doll powers in the Yellow arc have repercussions for both Red and Sabrina, which it prevents the former from becoming a Gym Leader in the next arc. Sird is also afflicted by this, where it seemingly led to her arriving at Spear Pillar late and having to wear warmth supporters like Jupiter.
- Blue found a book in the Viridian Gym called "Mysteries of the Earth", which was handy in training his Rhydon to fight Chuck. His Rhydon would also go on to save Silver and Giovanni from the burning wreckage in FRLG arc. Lastly, the book shows how to evolve Rhydon in the HGSS arc, something that wasn't revealed in the games until two generations after GSC.
- There was a series of monthly type magazine shown in Mt. Silver training chapter, which makes a reappearance in the XY arc.
- In the ORAS arc, Courtney’s memory firelighter was what led Ruby to learn about and look for Zinnia, while Blaise still had hold of the orbs tracker, leading him to team up with Amber.
- The last one in the RS arc is the unfinished artificial orb to control Rayquaza. Having been briefly mentioned in that arc, it's what led Emerald to create a new image for himself, and Ruby even speculated that it was what allowed Emerald to calm hundreds of rental Pokémon. It finally becomes complete in ORAS arc, allowing Ruby and Sapphire to control Rayquaza.
- The Red and Blue orbs also don't lose in that department. Having been shattered by Celebi, they still remain relevant in the next arc as the Ruby and the Sapphire that lets Deoxys access its Hoenn forms. And in the ORAS arc, they revert back to their old forms which are required for Primal Reversion.
Chekhov's Classroom
- Pearl is told by the Fan Club President that in order to prepare for Platinum's first Super Contest performance, each member of the Sinnoh Trio must do one different part. Much later on in the story, Pearl notices the ribbon that Platinum's Empoleon won and remembers the President's words. He then declares that each of them must go to and protect one different lake, marking the first time in their journey together that the three of them would have to travel alone.
Chekhov's Gag
- At the beginning of the GSC arc, Gold intentionally gives Facial Composite Failure the wrong description for Silver's wanted poster so that he would be the only one to go after him. At the end of the arc, this intentional mismatch would be what prevents Blue from apprehending Silver for his crime.
Chekhov's Gunman
- Almost every minor characters and even Pokémon introduced in the series becomes important later on. Some of them even become main characters.
- The Gyarados that Red saved Misty from comes back to save him from a Dragonite in Route 19, and Misty even gives it to him in exchange for his Crabby.
- The girl Red saved from a rampaging wild Dratini in the RGB arc was actually Yellow. Would have been more obvious if not for the hat...though we're not told whether Red knows Yellow's that same girl or not.
- The fisherman that appeared in the Indigo Plateau turns out to be Yellow's uncle.
- Crystal catches a horde of Remoraid just before entering Whirl Islands, which end up saving Gold along with a Mantine in their fight against Lugia.
- The little kid in a silhouette that appeared at the epilogue of GSC arc is revealed to be Emerald.
- Another major one is the female scientist who was working on constructing the Green Orb, who was only shown in flashbacks. It turns out she's Platinum's mother.
- Roark said that he was busy digging the cave with his grandfather, the Underground Man. While barely mentioned, the Underground Man later serves a crucial point near the end of the arc by using the Explorer's Kit to take the gym leaders to Mt. Coronet.
- Regigigas, savior of Platinum, Candice, and Maylene, and also savior of the space-time continuum.
- Blake decides to get an Escavalier in the Abyssal Ruins. It lets him win against Colress in their final battle.
- There was a girl in Team Aqua with glasses and braided hairs appearing now and then...turns out she was Zinnia undercover.
- Sun's grandfather was shown very briefly at the very beginning of the arc. Turns out he passed away and was the whole cause behind Sun's goal to raise money.
Chekhov's Skill:
- Blue's Porygon. When he and Yellow were fighting off wild Mankey it was shown to be able to travel through electrical systems. Later on in the FRLG arc it did it again to destroy the supercomputer that was holding Prof. Oak captive.
- Gold's prowess with a pool cue in his introductory scene is used a handful of times throughout the series and allows him to get the drop on the masked man in their showdown.
- Before a Gym battle Platinum will typically learn a new skill, which she will then have to use in said Gym Battle to beat the Leader. One notable example is her roulette skill from Veilstone Game Corner, which proves pivotal in defeating Maylene and even helps her out in Battle Arcade.
- The most recent example are the Pledge moves. First used by Black and Cheren in the Cold Storage, it wouldn't be used again until the next arc, by 3 sets of Unova Starters in a way reminiscent of the Emerald arc finale.
- Similar to Platinum, Soudo trains with Marvin before a Gym Battle, which proves useful in him defeating the Gym Leader. Such examples include Twiggy's boomerang-like sticks against Nessa or Tearie's water bombs against Opal.
