In Japan, black carp were known for their courage and strength, and streamers and banners depicting these carp were used as symbols by samurai warriors. The streamers or ‘windsocks’ are known as Koinobori, while the carp are known as koi.
Today Koinobori are used on Children’s Day, 5 May. A pole is planted with a colourful streamer above, a black carp streamer below, representing the father, and then a red carp streamer for the mother, with smaller and different coloured streamers representing the children. Initially Children’s Day was known as Tango no sekku, or Boy’s Day, and was only to honour sons. It used to be celebrated according to the lunar calendar, but was fixed on 5 May, after Japan began using the lunar calendar. Girl’s Day was on 3 March. But in 1948, Boys Day was renamed Children’s Day, celebrating the happiness of both boys and girls, and 5 May became a national holiday. Apart from carp streamers, a kintaro doll too is depicted, riding on a carp. Kintaro is a folk hero, a child with superhuman strength. One of Kintaro’s fictional exploits, was the capture of a black carp.
In the Edo period , black carp were were popular with great artists who often depicted them in paintings or woodblocks.
Black carp have been selectively bred to create ‘brocade carp’. Selective breeding actually started in Japan in the 1820s, but today this has been refined, and these coloured carp are kept in ornamental ponds. White and red, known as Kohaku, are the most popular. Decorative carp are now avavilable across the world.
Masuji Ibuse [1898-1993], famous for his novel Black Rain, on the aftermath of the bombing of Hiroshima, also wrote The Carp, a story of friendship. Crazy Iris [Kakitsubata] is another of his works on Hiroshima, a species of Iris distorted by radiation.