Koi-nobori (carp streamer) (鯉幟)
Koi-nobori was originally a Japanese custom that started among samurai families in the Edo period. It's a flag made of paper, fabric and nonwoven fabric with a carp design on it, whereby a streamer swings in the wind in the shape of a carp, and it's decorated in the yard to wish for a male child's success on a rainy day during the rainy season until May 5 (old lunar calendar) of the Boys' Festival. It is also called Satsuki-nobori. It is currently decorated until May 5 of the Gregorian calendar (the solar calendar), and is used as a seasonal word of summer.
The season of decoration has changed, however, so the image became 'it is to be streamed under the blue sky on a sunny day during the late spring.'
Summary
On the historical event according to "Gokanjo" (History of the Later Han Dynasty), one of 24 dynastic histories of Chinese official history, a lot of fish tried to swim up a waterfall called Ryumon in the rapid stream of the Yellow River, but only carp could wax on and thus became dragons. Based on that, toryumon (gateway) became a symbol of success in life.
It was originally magoi (black carp) only, but since the Meiji period magoi and higoi (red carp) have been hoisted in pairs. However, since the Showa period the one with kogoi (blue carp) has been mainstream in representing the family. However, only the black-and-blue combination was seen transiently.
More colorful kogoi, such as green and orange, have recently become popular, and some households hoist carps for all family members, including girls. The increase in kogoi depicted in warm colors is a response to such demand.
It is common to have a rotating sphere and kagodama (round ornament), to put a windmill below that with a streamer having five colors or a carp design on the top, and to hoist magoi, higoi and others in the order of size.
In urban environments, due to the housing conditions after the 1980s (a drop in single-family homes with gardens but increased collective housing such as apartments) and the declining birthrate, one would see far fewer koi-nobori hoisted high up in the gardens of private residences, as once described in children's songs.
On an expressway, it is often the case that the streamers used to indicate wind velocity and direction are replaced with koi-nobori during the period of April and May.
Also, there has been a case in which certain gender-free debaters criticized koi-nobori as a symbol of the feudalistic family system, so some autonomous bodies have instructed that koi-nobori should be hung up horizontally instead of vertically so as not to recall rank within the family, thus encouraging a society of gender equality.
However, the criticism of koi-nobori from the gender-free standpoint was countered by Tokyo Governor Shintaro ISHIHARA of the Tokyo Metropolitan Assembly (the second regular meeting in 2004), who said 'it is an extreme and bizarre allegation that even denies traditional culture.'
Process of origin
As it is said that 'a typical person from Edo is the streamer of carp in May'; and although koi-nobori (鯉幟) is called 'nobori' (幟) (flag), it's a streamer whose shape mimics a fish.
Koi-nobori was originally a custom that started among the families of affluent common people in the middle of the Edo period, as did Kadomatsu (New Year's pine decoration) and Hina-ningyo (a doll displayed at the Girls' Festival).
Because iris is used to drive away evil spirits during the Boys' Festival, it's also called 'Iris Festival.'
By bringing 菖蒲 (pronounced "shobu") (iris) and '尚武' (pronounced "shobu") (martial spirit) together, it became the annual event in which to pray for a male child's success and longer fortune of war among samurai families.
On this day, samurai families would take ancestral armor and kabuto (helmets) to the inner parlor (also for the purpose of airing them) and place decorated hatasashi-mono (battle flags) in the hallway; and the family heads would give instructions to their children.
On the other hand, merchant families, who were seen as being of lower social rank despite their considerable economic power, hired the creation of replicas of luxury arms against the samurai, as well as beautifully decorated five-color streamers instead of nobori, according to illustrations on kibyoshi (an illustrated book of popular fiction whose cover is yellow).
Furthermore, some households might have felt that decorating streamers only was insipid, so they started drawing carps on the streamers based on the origin of 'Ryumon.'
The fish-shaped koi-nobori is derived from that.
Major events
There are events associated with koi-nobori in many parts of Japan.
Kazo City, Saitama Prefecture, which has been at the pinnacle of koi-nobori production since the prewar period, gained fame in February 1988 when it created the world's longest koi-nobori, measuring 100 meters in length and weighing 350 kg. It introduced Kazo City to the outside world as Kazo's koi-nobori with the top production of koi-nobori. It showed its brave figure at the riverbed of the Tone-gawa River at the Public Peace Festival, which takes place in the city each May.
At Tsuetate-onsen Hot Spring in Oguni-machi, Kumamoto Prefecture, 3,500 koi-nobori are hoisted.
In Ino-cho, Agawa-gun, Kochi Prefecture, which is active in the production of Japanese paper, koi-nobori made with Japanese paper that does not rip when dampened is released into the Niyodo-gawa River, so on boat tours one can see koi-nobori swimming in the river.
200 koi-nobori swimming over the breadth of the river are lit up from water between O-hashi Bridge and Umeno-hashi Bridge on the Asano-gawa River, which runs through Kanazawa City, Ishikawa Prefecture.
In the Otani area of Suzu City, Ishikawa Prefecture, multitudes of decorated koi-nobori span the Otani-gawa River at the beginning of May.
In Tokawa, Shimanto-cho, Takaoka-gun, Kochi Prefecture, which is midway along the Shimanto-gawa River, the Kawa-watashi (passing over a river) of 500 koi-nobori takes place from the end of April to the beginning of May, and this place is known as its origin.
(Since 1974)
In Tatebayashi City, Gunma Prefecture, the hometown festival of the world's best koi-nobori takes place from the end of March to the middle of May. More than 5,000 koi-nobori are hoisted in four places at the Tsuruuda-gawa River, Morinji-gawa River, Kondo-numa Pond and Tsutsujigaoka Park Inn. The number was registered with the Guinness World Records organization in 2005.
School songs and children's songs
Koi-nobori is mentioned in some school songs and children's songs.
Lyrics: Kume HIGASHI; music: "Koi-nobori," composed by Rentaro TAKI
Lyricist unknown; music: "Koi-nobori," composed in 1914 by Ryutaro HIROTA
Lyrics: Miyako KONDO; music: "Koi-nobori," composed in 1931, composer unknown
Particularly, the third one in the spoken version and the second one in the literary version are famous.
Others
Koi-nobori is used in and out of season as one of the cheering goods for professional baseball's Hiroshima Toyo Carp.
As a short physical display, it's sometimes referred to as 'human koi-nobori' or 'koi-nobori' in holding the pole that stands vertically and elevating the body parallel to the ground. This is also referred to as a human flag in Japan, but that isn't a standardized term. It requires a strong grip, brute strength, and muscular abdominals and trunk, and the degree of difficulty is high. The common English term for this is "human flag."