Illustrated Japanese Culture

Koinobori: carp that catch the wind

鯉のぼり

Koinobori are hollow carp-shaped streamers displayed around 5 May, carrying wishes for children to grow well. Wind enters their open mouths and fills their flexible bodies, making the fish appear to swim.

Colored carp streamers below a fukinagashi; Kintarō appears on the black carp.

5 MayAssociated with Tango no Sekku and Children’s Day.

Open-endedAir passes through a flexible fish-shaped tube.

Changing formsMaterials, colours and displays have changed over time.

Why the fish “swims”

A windsock, not a stuffed fish

The mouth is held open, while the narrower tail also has an opening. Moving air fills the flexible body and makes it flutter. Without enough wind it hangs down.

Read the parts of a display

A familiar pole arrangement has a top ball and arrow-wheel, a striped fukinagashi streamer, and carp of different sizes and colours. The ribbon-like fukinagashi is not another fish. The Japan Doll Association connects its five colours with the five phases and explains the arrow forms as protective symbols. Arrangements vary.

Why a carp—and why a banner?

Hiroshige, Suidō Bridge and Surugadai, 1857: carp streamers and upright banners share the skyline.

A carp that becomes a dragon

The Chinese story of a carp ascending a waterfall and becoming a dragon supplied an image of striving and success. It became a subject in Japanese art associated with the fifth-month festival.

Warrior banners and townspeople’s carp

Edo townspeople developed carp-shaped streamers in relation to the warrior custom of displaying banners for Tango no Sekku. Hiroshige’s 1857 view of Suidō Bridge and Surugadai shows carp streamers alongside upright banners. A description of paper carp also appears in the 1838 Tōto saijiki. These records show an established custom.

From paper to cloth

A hand-painted paper carp, 3.2 metres long, at the Japan Toy Museum.

Large fish could be made from paper

Early carp streamers were made from paper. The Japan Toy Museum preserves an undated, hand-painted washi carp 3.2 metres long. Paper examples can also carry figures such as the legendary strong child Kintarō.

An undated photograph of carp-streamer making in Kazo: artisans paint the spread-out fabric.

Cotton and synthetic fabrics

Cotton examples appeared in the Meiji period; cotton and synthetic fabrics expanded after the war, with nylon and polyester common today. These materials did not replace one another everywhere at a single moment. In Kazo, lantern and umbrella makers began carp-streamer production as a sideline in early Meiji times; orders redirected after the 1923 earthquake helped it become a specialised trade.

The colours did not always mean the same family

Black and red carp made around 1949, each 5.8 metres long. Museum of Ehime History and Culture.

From one black carp to pairs

A single black carp was common in Edo displays. Black-and-red pairs became more widespread from later Meiji into Taishō times. A surviving pair made around 1949 in Yawatahama, now in Ehime’s history museum, has two fish each 5.8 metres long. The supports used to hold them out in the museum are display equipment, not their usual outdoor structure.

Red once meant the child

A familiar children’s song from the 1930s describes the black carp as the father and the red carp as a child. A later common reading makes red the mother and smaller blue or other coloured fish the children. Additional colours were appearing during 1955–64; they were not simply invented for the Tokyo Olympics. Family readings and colour choices developed over time.

Tango customs · Historically associated with boys
Children’s Day, 1948 · Children more broadly

Children’s Day is a separate historical change

The 1948 public-holiday law established Children’s Day on 5 May, with respect for children, their happiness and gratitude to mothers in its purpose. The older Tango customs were especially associated with boys; the public holiday concerns children more broadly. The law did not prescribe the colours or family roles of carp streamers.

From a household pole to a public display

Make room for the fish

Large garden poles, smaller balcony sets and indoor ornaments serve different spaces. An indoor version need not inflate in the wind. Size and setting help explain why a modern decoration may look quite different from the enormous outdoor fish in an Edo print.

Carp streamers across the river at Tōkawa, Shimanto: a recent view of the event.

Across the Shimanto River

Tōkawa in present-day Shimanto Town began stringing carp across the river in 1974. The practice grew from a local initiative involving children and a sports association. River-wide installations turn separate household streamers into a shared seasonal view.

Kazo’s first-generation giant carp, 100 metres long.

A hundred-metre carp in Kazo

Kazo’s first giant carp was made in 1988 and, after adjustments, had its first official flight at the city’s peace festival in 1989. Its length was 100 metres. This is a deliberately exceptional festival object, not the normal size of a household koinobori.

Nonwoven paper carp in the Niyodo River, pictured on Ino’s May 2025 town bulletin.

Fish displayed in the water

In Ino, special carp made with local nonwoven material are displayed in the Niyodo River itself. Their material makes a different kind of installation possible: the fish move with the river water rather than the wind.

The blue-carp memorial project in Higashimatsushima, from a Miyagi prefectural bulletin published in May 2019.

Blue carp in remembrance

The Blue Koinobori Project in Higashimatsushima commemorates children who died in the 2011 disaster. Here a colour takes on meaning through a particular community project. Blue carp elsewhere should not automatically be read as memorials.

Festival carp · Wishes for children
Around Ōi Shrine · Carp treated as sacred; no carp streamers
Commercial fish windsocks · Shop promotion

A local custom of leaving carp unraised

Around Ōi Shrine in Kameoka, carp are regarded as messengers of the deity. Local custom is to avoid eating carp and to leave koinobori unraised. The shrine’s tradition is one example of how observance differs by place.

Fish for shopfronts and events

Manufacturers also make fish-shaped streamers depicting mackerel, tuna, sea bream and pufferfish. Fish markets and shops use them for promotion and events, giving the wind-filled form a purpose beyond the seasonal carp display.

What can you now explain?

How does a koinobori inflate?

Air enters the open mouth and passes through the flexible body toward its smaller, open tail.

Is the striped streamer another carp?

No. It is a fukinagashi, a separate ribbon-like part of many displays.

Why is the carp an auspicious choice?

The carp-ascending-a-waterfall legend connects it with effort and success.

What does Hiroshige’s 1857 print show?

Carp streamers and upright banners together in an Edo cityscape; it is evidence of an existing custom, not its invention date.

Were carp streamers always synthetic cloth?

No. Paper examples came earlier; cotton and later synthetic fabrics became widespread.

Has the red carp always meant the mother?

No. The 1930s song describes it as a child; family interpretations changed.

Did the Children’s Day law set the colours?

No. It established the public holiday, not streamer colour rules.

Are the river and giant-carp displays unchanged ancient customs?

No. The examples here have specific modern histories: Tōkawa from 1974, and Kazo’s first giant made in 1988 and officially flown in 1989.

Does every blue carp commemorate the disaster?

No. That meaning belongs to the Higashimatsushima memorial project and its context.

Do all communities follow the same display custom?

No. Around Ōi Shrine in Kameoka, carp are treated as divine messengers, and local custom is not to raise koinobori.

Sources and images