A character is being threatened with violence, and tries to tough-talk his way out. Only, he can't legitimately claim to know karate or anything remotely scary, so he threatens the opponent with some random foreign-sounding words as a bluff, hoping the enemy will be too dumb to understand. The most common variant involves origami, the Japanese term for paper folding art, but just about any foreign word will do.
In fiction, this actually tends to work at least half the time, with the opponent backing away nervously, or at least hesitating long enough for the Big Damn Heroes to arrive. This can easily be subverted, however, if the opponent actually turns out to know what origami/Hitachi/Pachirisu actually is.
Compare/Contrast My Hovercraft Is Full of Eels, As Long as It Sounds Foreign, I Know Kung-Faux. If the character actually does have a black belt in origami, it's Martial Arts and Crafts and/or Paper Master. Pity the opponent who mistakes either one for this trope.
- In an issue of Spider-Man 2099, Spidey warns an attacking samurai assassin: "I know karate, kung fu... and several other dangerous words."
- Variant: in Mafalda, Manolito describes how samurai stab themselves with their own swords "and make the Ikebana". Once Mafalda disses him off saying that is a flower arrangement, he tries to save himself with "It's the funeral, stupid!".
- Knights of the Dinner Table: During a Hacknoia campaign, Bob maxes out his character's skill in Tai Chi — thinking that it is a kickass martial art — because it is cheap. It is only after he gets into a fight that Sara explains that it is a form of moving mediation.
- The Trope Namer - In Recess: School's Out, TJ yells this at the Mooks dragging him off from his escaping friends.
- In Ella Enchanted, Ella encounters Mooks bullying the elf Slannen. After he (semi-unintentionally) orders her to help him, she threatens the Mooks with origami. Unfortunately, one of them actually knows what that is.
- In Teenage Mutant Ninja Turtles III when the Turtles get sent back to feudal Japan, Donatello greets someone by saying 'Konichi wa Wasabi' which Raph immediately lampshades by confusedly asking 'Hello Mustard?'
- In Transformers, when being taken in for questioning, one of the characters claims that he has a black belt in karaoke.
- In the Doctor Who New Adventures novel Transit, the Doctor gets past some Japanese Mooks by using the court dialect of the Japanese royal family. They recognised it, but didn't understand it, which was just as well, since he said "Make way, for I am the official keeper of the Emperor's penguins and his majesty's laundry basket is on fire."
- The Captain's Daughter, a Star Trek Expanded Universe novel by Peter David, has the same line as Spidey 2099 almost word-for-word. (Not a big surprise, as David was the co-creator and writer of Spiderman 2099.)
- In one of Beverly Cleary's Ramona books, one of Ramona's classmates wants to "prove" that he mastered karate over the summer on the first day of school, so he jumps in front of her and shouts "Ho-ha!" (instead of "Hai-ya!")
- In book two of The Trials of Apollo, Calypso attempts to scare away Commodus' Mooks by pretending to curse them. Apollo notes that her chant is really a recipe for waffles.
- The exact line is used in Only Fools and Horses "Cash and Curry" by Del, as he attempts to bluff an ability in martial arts.
- At one point in Friends, Ross insists that he knows a martial arts technique called "Unagi." Rachel and Phoebe, however, know what the word actually means and spend much of the episode after making jokes about it.
- Inverted in a How I Met Your Mother episode. Ted knows that his girlfriend practices "krav maga" but assumes that it's something like yoga. He finds out that it's a fighting style the hard way.
- On one episode of The Slammer the Governor employs a robot warder called Wardrobe 2000 who is expert in "karate, jujitsu and the macarena".
- In an episode of Passions Luis and Sheridan walk in on Julian and Rebecca in a compromising position. Julian claims to be showing Rebecca an origami move. Luis snarkily responds, "Yeah, I heard you had a black belt in origami."
- Patsy from Camp Lazlo claims to have a black belt in bok choy.
- The origami version appears in the Animated Adaptation series of The Faraway Tree.
- In one Dexter's Laboratory episode, Dexter lost the ability to speak anything except the phrase "omelette du fromage" and used it to ace tests, scare away bullies, seduce women, win gameshows, create world peace, and release a solo album, among other things. Though his scaring away the bullies is probably the most straightforward use of the trope. Incidentally, at the end of the episode, his new phrase, while working with everything else, did not count as his lab password. He's left crying on the floor when it self-destructed.
- A Scooby-Doo, Where Are You! episode has Shaggy trying to bluff a Chinese ghost by saying "I know Judo, Chop Suey and Chinese checkers!"
- There was one episode of The Simpsons when Homer was trying to bluff his way into getting a veteran's discount by pretending to have served in Vietnam. He shouted several Asian words (up to and including Margaret Cho) as reference to specific battles he was supposedly involved with.