There's an ancient Japanese legend that states if someone folds a senbazuru — an arrangement of a thousand origami cranes tied together — a crane will come to them and grant them a single wish, such as long life or recovery from serious illness or injury. They are also a popular wedding gift (symbolizing a wish for a long and happy marriage), due to the immense time involved.
In modern times it has grown to be been used as a symbol for world peace, spawning from the story of Sadako Sasaki, a girl who died of leukemia from the Hiroshima bombing in World War II. More information from The Other Wiki.
There is something similar called Senninbari. Senninbari was a strip of white cloth, approximately one meter in length, decorated with 1000 stitches in red thread from 1000 women, used as an amulet given to soldiers on their way to war as a part of the Shinto culture of Imperial Japan. The belts were believed to confer courage, good luck and immunity from injury (especially bullets) upon their wearers. See this entry in The Other Wiki for more, though really the fact that today the Kaiju Defense Force uses kevlar ballistic armor like everybody else (not to mention the fact that it's a defense force and not an actual army anymore) should tell you just about everything you really need to know.
This is not to be confused with the Yasunari Kawabata novel "Thousand Cranes", the title of which refers to a certain handkerchief pattern.
- Wrigley's Extra chewing gum released an ad in the fall of 2013, showing a father folding tiny origami cranes for his daughter out of Gum wrappers. The final scene is of the family loading the car with the daughter's belongings as she is moving out, presumbly after college. A small box falls from the top of a stack and lots (maybe not a thousand) of tiny silver gum-wrapper cranes spill out of it. The tagline is "Sometimes the little things last the longest. Give Extra, get Extra."
- In Kodomo no Jikan, after Rin's Ill Girl mother Aki began to falter in health, Rin started making cranes day after day in an attempt to keep her alive, and Aki was covered in them when she finally died. Worse still, in Chapter 70 she states that she felt that the reason Aki died is that she couldn't complete all thousand.
- In Code Geass, Nunnally gets taught Origami by Sayoko and tells Lelouch about the Thousand Origami Cranes. In the Grand Finale, C.C. carries an origami crane with her as she starts Walking the Earth after Zero Requiem. This actually created the Epileptic Tree that the emblem of the Black Knights, Lelouch's La Résistance, is meant to be a paper crane viewed from the front — representing his promise to make the world a better place for Nunnally.
- In an episode of Ghost in the Shell: Stand Alone Complex Second Gig, Major Kusanagi hears a curious story. The boy later known as Hideo Kuze was injured in a plane crash and mostly paralyzed except for his left hand, which he would use to endlessly fold paper cranes in hopes that the girl next to him would recover from her injuries, but she took a turn for the worse and was taken away. He was later visited by a girl with a cyber-body who suggested that he should have his own body replaced. He said he'd do it if she could prove to him that such a body could fold paper cranes just as well as he could now. No matter how she tried she just couldn't. In spite of this, he did later get a mechanical body. The Major seems to find the story familiar, and at the end we see that she has folded a paper crane with one hand...
- A touching variation in Azumanga Daioh: The girls are taking their college entrance exams, and Osaka, being Osaka, suggests they try to perfectly break apart a pair of chopsticks for good luck. Chiyo—who doesn't have to worry about exams herself because she's going to the US—later buys several hundred chopsticks and splits them one by one while the others take their exams in order to wish them luck.
- In Flame of Recca, Saicho, who has the ability to control paper, is given a thousand paper cranes that he uses for his ultimate attack against Recca.
- After the latest in a long line of traumatic experiences, Shadow Star's Shrinking Violet Akira Sakura cut school for weeks and holed herself up in her room. When her friend Shiina (and... acquaintance Sudo) came to see her, they find she's (apparently) been spending her time trying to make a thousand paper cranes, one for each of the soldiers Satomi previously killed.
- In Big Windup!, the cheer team for the protagonist's teams opponents in the baseball tournament made them 1000 Origami cranes to wish them good luck in the tournament. After they lose, they give the cranes to the Nishiura team.
- Folding paper cranes shows up as a somewhat fitting remuneration in the second season of Darker Than Black.
- Another variation: In Barefoot Gen, Gen and his brother Shinji decide to make "a thousand-stitches belt" and go to town to ask people to contribute stitches. The belt is meant to be a gift to their oldest brother, who's going off to fight in the war soon (this is also Truth in Television, see the "Real Life" folder below and the trope description above).
- Played for laughs in Kaguya-sama: Love is War spin-off series We Want to Talk About Kaguya, where Erika folds 1000 cranes for Kaguya's health when she's out sick for two days with a fever. Of course, Kaguya had already gotten better by the time she finished and Karen wouldn't allow her to give them too her personally on the grounds that it would be creepy, so they just hang them in their club room instead.
- This is the main hinge of Caterpillar Girl And Bad Texter Boy, where a wish will be granted if someone writes it on a piece of paper, folds it into a crane and leaves it as an offering to a small shrine in the forest. This is how Suzume became a giant caterpillar and the first place Akane starts looking for to restore Suzume to human form.
- The story of Sadako Sasaki is referenced in the 1993 Mushi Productions anime film Tsuru ni Notte: Tomoko no Boken (On a Paper Crane: Tomoko's Adventure), about a girl named Tomoko (played by Kotono Mitsuishi) who visits the Hiroshima Peace Memorial Park, where a monument to Sadako stands, and befriends Sadako's spirit.
- Haruhi Suzumiya combines this with If I Had a Nickel in Kyon: Big Damn Hero:
"If I had a paper crane for all of the things that Kyon's done for me, I'd have a wish by now!"
- In Come Find Me, Again, we have Satsuki, after being hospitalized, being mentioned to have folded origami cranes at the end of chapter five. It was also mentioned that she wrote little notes on them.
- Similarly, in an otherwise unrelated fic, titled Paper Cranes, we have an Ill Girl Satsuki being mentioned to have done this in letters dated "June 3rd" and "October 15th" that Ryuuko addresses to her.
- Cinders and Ashes: the Chronicles of Kamen Rider Dante establishes Kotoha as an Ill Girl through a hospital visit where Honoka quickly notices two dozen or so paper cranes and puts two and two together.
- In i am sam, the titular hero is a mentally challenged single father who has lost custody over his 7 year old daughter Lucy. He builds a wall of origami figures in his apartment, supposedly hoping for the legend to come true to get him his daughter back. It seems to come true, at least partially, as the ending suggests that custody for Lucy is shared between him and the foster family.
- As mentioned in the trope description, this is a major part of Sadako and the Thousand Paper Cranes. Based on a True Story, Sadako, born in Hiroshima two years before the atom bombs fell, contracts leukemia and attempts to fold 1000 paper cranes because of the legend that doing so will grant her one wish. She dies with only 644 completed, but her classmates finish the rest and she is buried with them. According to Sadako's brother, however, it is untrue that Sadako died without meeting her goal, and she actually managed to fold around 1400.
- In Extras, the fourth and final book in Scott Westerfeld's Uglies series, this seems to have become a rite of passage for 15-year-old girls in the futuristic Japanese setting. There's also a trend of mailing one's thousand cranes to a favorite male celebrity; protagonist Aya's famous brother has an apartment full of them.
- Sulu folds a thousand cranes while in Starfleet Academy, as he relates in The Kobayashi Maru. He learns from it that it's not about the wish - it's about the effort you are willing to put into the wish.
- Used in a season 4 episode of Eureka in the same manner as the JSA astronaut example given in the Real Life section. Several Astraeis candidates are sealed in a small room together and tasked with each folding 1000 cranes in order to test their ability to do complex repetitive tasks. They're also given an extra person posing as a stowaway that they need to prove they can deal with sharing limited space and resources with.
- In Heroes, Hiro proves to Charlie he has the power to freeze time by filling a room with 1000 Origami Cranes - and it's also a way of saying his intentions, because he's working against time to prevent her death.
- The Mentalist: Patrick Jane is accomplished at origami. He gifted Lisbon with a jumping origami frog as a peace offering in "Pilot". In the seventh-season episode "Nothing But Blue Skies", he slipped an origami crane into her pocket.
- Katamari Damacy: One level in We ♥ Katamari requires you to roll up a thousand cranes to help a boy whose sick friend is in the hospital. The closer you get to the full 1000 cranes, the better your score.
- In Mega Man Battle Network 3, there are 1000 (unseen) origami cranes in a room of the hospital. You need to take one in order to advance the plot.
- The opening of a case in L.A. Noire shows a man in a dark room folding origami cranes amongst many others. Later on, Phelps makes reference to this particular legend when he sees the room.
- At the end of Solatorobo, the kids at Red's old orphanage decide to try folding a thousand paper cranes, and Red agrees to get some help. He then revisits every major location in the game and convinces everyone, including the new leader of the Kurvaz, to make as many cranes as they can and send them to the orphanage.
- In Disgaea 3: Absence of Justice, the apply named Asuka Cranekick is known to enjoy folding paper cranes. She even once promised to Almaz, who is covering the fact that he is slowly dying by pretending to be sick that she will fold thousand paper cranes to them so that they can rest in peace. She even suffered from demon leukemia, and would have suffered from it even to this date if Raspberyl hadn't donated bone-marrow for her.
- In Persona 4, the Player Character can spend time in his room folding cranes, which increases his Understanding statistic. Unlike other jobs this can be done during spare time, doesn't bring money, but once the set's complete it gives an item. How long it takes to do so depends on which choices are made and whether they work out well - generally, one choice gives you the standard progress, while another can either make the PC work faster or slow down.
- In Fire Emblem Fates, the supports between Princess Hinoka and Hayato involves her teaching him to fold cranes.
- Played for Drama in Paper Mario: The Origami King: King Olly is hoping to fold 1000 cranes so he can make a wish to eradicate all the Toads because the Toad who created him scribbled on his paper which he took as a great insult, and all Toads look alike, so he was seeing the face of the guy he hated everywhere he went. By the end of the game, he's folded 999 cranes, and plans to fold Mario into the 1000th. After he is defeated and learns that the "scribble" was actually a message from his creator hoping he would be a kind and wise king, he suffers My God, What Have I Done? and requests that Olivia fold him into the 1000th crane and make a wish. She does and makes a wish to undo all of his creations, which unfortunately includes herself.
- The title of an episode of Lime-iro Senkitan. When Sophia is in the nurse's office with her mental state regressed, Momen and the girls offer to do something for her, and come to this conclusion. Sarasa has the most trouble with it.
- In Hanna Is Not a Boy's Name, a paper crane appears before [...] as a sort of spiritual guide. According to Hanna, the guide takes on the form of something with emotional significance for each individual, but since [...] doesn't remember anything about his life before he died, whatever meaning it had for him is more or less gone. Hanna decides that's too depressing, so he starts folding 1,000 cranes to grant a wish, "so it can mean something again." (Touchingly enough, fans of the series have started folding their own cranes to help out. You can find their progress on their DeviantArt group page.)
- Folder from the Whateley Universe has folded several sets of a thousand paper cranes (his power is folding anything). He finds it relaxing.
- The most famous attempt and (sad) subversion: Hiroshima bombing victim Sadako Sasaki, who reached one thousand and continued to fold more up 'til her death. (Which is only one version of the story — another states that she completed 644 before she could not continue, and her friends finished the thousand.)
- Perplex City had a card entitled "Sadako Sasaki" based on this.
- Don't forget the band Hiroshima's touching song Thousand Cranes, dedicated to Sadako. The song even urges people to 'send her your thousand cranes' to 'show her we do care.'
- Sadako's story inspired the Children's Peace Monument; to this day people send folded paper cranes in honor of those who died of the bombs of Hiroshima and Nagasaki, and to heal the world of wars. Several temples in Japan also have eternal flames burning with Senbazuru displayed nearby for the same reason.
- Folding a thousand origami cranes is one of the possible testing procedures for would-be JSA astronauts, which author Mary Roach observed while researching Packing For Mars. By setting a narrow time limit for a complex and repetitive task, observing the candidates' work, and then examining their finished cranes for consistency over time, the Japanese Space Agency's psychologists can assess applicants' ability to handle the kinds of stress, boredom, and meticulous detail-work that is common on ISS space missions.