Thousand Origami Cranes

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.

This is not to be confused with the Yasunari Kawabata novel "Thousand Cranes", the title of which refers to a certain handkerchief pattern.

Anime and Manga

 * Pictured above: 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.
 * In Code Geass, Nunnally gets taught Origami by Sayoko and tells Lelouch about the Thousand Origami Cranes.
 * Also note that Lelouch's sigil when he uses his geass has a flying crane shape and his goal of creating a peaceful world for Nunally. This is reinforced by the later metaphor of geass = wishes.
 * In an episode of Ghost in The Shell Stand Alone Complex Second Gig, Major Kusanagi hears a curious story. The boy 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, Narutaru'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 Ookiku Furikabutte, 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..
 * Folding paper cranes shows up as a somewhat fitting renumeration 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.

Literature

 * Folder from the Whateley Universe has folded several sets of a thousand paper cranes (his power is folding anything). He finds it relaxing.

Live Action TV

 * 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.

Video Games

 * One level in Katamari Damacy requires you to roll up a thousand cranes to help a boy whose sick friend is in the hospital.
 * 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 LA 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.

Visual Novels

 * 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.

Webcomics

 * In Hanna Is Not a Boys 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 Deviant ART group page.)

Real Life

 * 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 Senbadsuru displayed nearby for the same reason.
 * Sadly, not everyone agrees with the legend of a thousand cranes. The Book Of Ratings has this to say about them.