In Chinese and Japanese law, one needs a stamp to "sign" documents in one's name—"signatures" as Europeans know them are an impossibility as written Chinese doesn't have an alphabet. Also called a "chop", one's stamp must to be registered with the authorities before it is officially recognized. These stamps, referred to (by the Japanese) as hanko, or inkan, are used with red ink to mark a document.
The inability to locate one's inkan can be a delaying action to build tension or comedy, as appropriate. Alternatively, a person can accidentally stamp a document far more easily than they might sign one, leading to unintended results.
The practice was once common among European nobility and royalty (who at some points in history could have been illiterate, so could not literally sign documents, and as such needed some other way to give them their "seal of approval"), specifically through the use of signet rings to impress a personal seal into wax bindings on messages. (Wearing your personal seal on a ring also prevents the usual application of this trope, conveniently enough.)
- Hand Maid May: Kazuya Saotome receives a package from the Cyberdyne Company, he needs to go look for his seal. When he turns around, however, the delivery person is nowhere to be found.
- Please Teacher!: Kei Kusanagi is filling out forms to officially marry Mizuho, ostensibly to protect themselves from reprisals from his school. He is very hesitant about whether this is right to do, but a distraction takes the decision out of his hands, causing him to accidentally put his stamp on the paper.
- Excel Saga: The Cold Opening for every episode, often has a scene of Rikdo Koshi's personal seal being used to signify his 'approval' of the contents of the episode, whether this is a Dating Sim, action movie, science-fiction movie, or whatever Nabeshin and company came up for that week.
- It also features probably the most over-the-top usage of a stamp in anime: in one of the openings, we see a huge meteorite destroying an entire city and carving an enormous crater... and the meteorite turns out to be a building-sized version of Rikdo Koshi's stamp.
- Another episode has the production crew forge the stamp so they can do an episode that Koshi didn't approve.
- Despite driving like a maniac for her driving tests, Natsumi in You're Under Arrest! gets a driving licence anyway, since the examiner passed out during the test, conveniently letting the stamp fall on the requisite box on the form.
- Zeniba's golden seal in Spirited Away turns out to be a major plot point, and in one DVD special the English staff talk about the addition of the word "golden" to keep the mostly young audience from mistaking it for the other type of seal that barks and dives underwater, viewers being morons and all that.
- And since the seal is in essence Zeniba's name, her sister's theft of it is not just robbery, but an attempt to gain magical power over her.
- A package being delivered, and the subsequent search for the seal, takes the place of the opening sequence in the first episode of Seven of Seven. It also allows us to see the deliveryman get totally freaked out, and prove that voice actors can count to seven and deliver Title Drops at the same time.
- In one episode of Occult Academy, Maya refuses to approve Fumiaki's proposal to allow Mikaze's shop to sell bread at the school. In fact, she throws her official seal at his head hard enough to leave a mark and enough ink for him to transfer to the paper.
- In the movie "A Taxing Woman" tax evaders use all sorts tricks to hide the extra personal seals associated with their hidden bank accounts.
- Adron's personal seal is an important plot point in The Phoenix Guards.
- An example of the western version appears in Dan Brown's novel Deception Point. Evil Conservative Senator Sedgewick Sexton places self adhesive wax seals on manila envelopes which contain "evidence" that the president was behind a vast conspiracy to...make it look like aliens exist to
make himself even more insufferableimpress the journalists he plans to hand them out to.
- In Dune, the signet ring of House Atreides is brought up in multiple places. It is one of the things that Yueh makes sure heir Paul Atreides has with him when he's sent into hiding, and is considered to be of equal or greater importance than the launch and arming codes to House Atreides atomic weapons.
- I, Claudius brings us this in Ancient Rome. Gnaeus Calpurnius Piso has been receiving letters from Livia, with her late husband Augustus' Imperial Seal on them. She still has free use of that seal, and notes with annoyance that Tiberius (with good reason) never shares his seal with her.
- The Prince and the Pauper. The prince hides the Great Seal of England before "temporarily" swapping clothes with a Street Urchin.
- Another Ancient Rome example, from Chelsea Quinn Yarbro's Blood Games: Petronius asks that his seal ring be destroyed (with him watching) before he commits suicide, fearing that Nero would use it to forge evidence and invalidate his will.
- Discworld: In the events of Making Money, it is revealed that Lord Vetinari's signet ring is made of a special metal, possibly an alloy, that has the unique property of absorbing light and turning it into an intense heat. He stores it in a little wooden box when not stamping paperwork with it. While one of the villains who is obsessed with imitating him has an exact replica of the ring made and wears it all the time under a glove and since it's too small for him his finger turns gangrenous, fortunately Moist talks him into stepping outside into the sunlight without the glove, so the heat is intense enough to amputate and cauterize.
- Several show up in James Clavell's Asian Saga:
- Dirk Struan's chop is seen, and is stated to read "Green-eyed devil, dagger of the sea.", referencing his nature as a foreigner, a seaman and a man not to be crossed, as well as a Pun on his name.
- A sub-plot in Noble House involves Paul Choy stealing his father's chop to perform a business deal he knows to be profitable and good for his family, but his very traditional and conservative father disapproves of.
- In Trelane's backstory in the Mage Storms Trilogy, he once made a perfect copy of the Emperor's personal seal, and stored it in a booby-trapped desk. He would eventually use it to forge orders to allow him to strip an Imperial supply depot of everything his men could carry while the Gate remained stable after the Storms made communication and transportation with the Empire highly unreliable, allowing them to secure the resources needed to survive the winter.
- The Beverly Hillbillies: In "Jed, Incorporated", a running gag has Miss Hathaway use her notary seal to "mistakenly crinkle" corporate documents (or, so saith the hillbillies).
- Attila. When Flavius Aetius is restored to power by the mother of the Emperor, he insists she give him her seal to let others know that he's acting on her authority and is not still in disgrace. He then arranges for an assassin to kill the Emperor, using the seal to convince the assassin that she's arranged it, and even giving him the seal as a "Get out of Jail Free" Card in case he's captured. Aetius then kills the assassin just as he's about to strike, earning the Emperor's gratitude and sowing distrust when he finds his mother's seal on the assassin's body.
- The significance of the physical object is hard to overstate. In real life, local managers have stolen entire companies by making off with the chop.
- The custom is maintained in Western nations by the seals associated with most public offices, and notaries public in several jurisdictions have stamps and seals with their name and date of affirmation.
- For a while during the 18th century the Swedish monarchy had a personal stamp (created because it saved on time when there were too many things that legally required the king's signature). The use of it ended after the parliament confiscated it when the king refused to sign laws (it was an attempted ploy to claw back powers), declared that the previous acceptance of the stamping meant that constitutionally speaking the stamp could fill the legal role of the king, and used it to stamp laws themselves.
- In the events surrounding the conquest of Sweden by the Danish king Christian II in 1520, a number of Swedish notables were "asked" to sign and seal a document supporting Christian's claim to the throne. According to legend, bishop Wender Brask placed a note reading "Härtill är jag nödd och tvungen" ("Unto this I am forced and compelled") under the wax when putting on his seal. When Gustaf I Vasa drove the Danes out and began hunting down Christian's supporters, Brask broke his seal and displayed the note, which lead the king to pardon him for his involvement. How much of this is true and how much is legend is up for debate, but the document exists, Brask's seal is missing from it, and we know from other sources that Brask survived Gustaf's extremely thorough purges.
- Using a Private Cryptographic Key to electronically sign documents can be seen as the modern equivalent of this.