Renku (連句 "linked verses" ), or haikai no renga (俳諧の連歌, "comic linked verse"), is a Japanese form of popular collaborative linked verse poetry. It is a development of the older Japanese poetic tradition of ushin renga, or orthodox collaborative linked verse. At renku gatherings participating poets take turns providing alternating verses of 17 and 14 morae. Initially haikai no renga distinguished itself through vulgarity and coarseness of wit, before growing into a legitimate artistic tradition, and eventually giving birth to the haiku form of Japanese poetry. The term renku gained currency after 1904, when Kyoshi Takahama started to use it.
Traditional renga was a group activity in which each participant displayed his wit by spontaneously composing a verse in response to the verse that came before; the more interesting the relationship between the two verses the more impressive the poet’s ability. The links between verses could range from vulgar to artistic, but as renga was taken up by skilled poets and developed into a set form, the vulgarity of its early days came to be ignored.
Haikai no renga, in response to the stale set forms that preceded it, embraced this vulgar attitude and was typified by contempt for traditional poetic and cultural ideas, and by the rough, uncultured language that it used. The haikai spirit, as it came to be called, embraced the natural humor that came from the combination of disparate elements. To that end haikai poets would often combine elements of traditional poems with new ones they created. A well-known example of this early attitude is the opening couplet, possibly by Yamazaki Sōkan (1464–1552), from his Inutsukubashū (犬筑波集, "Mongrel Renga Collection").
He was given the following prompt:
- kasumi no koromo suso wa nurekeri
- The robe of haze is wet at its hem
to which he responded:
- saohime no haru tachi nagara shito o shite
- Princess Sao of spring pissed as she started
This poem clearly derives its humor from shock value. Never before in Japanese culture had anyone dared to talk of the goddess of spring in such a manner. Taking an ostensibly traditional and poetic prompt and injecting vulgar humor while maintaining the connection of the damp hems and the spring mists was exactly the sort of thing that early haikai poets were known for.
A comparable, though less evolved, tradition of 'linked verse' (lién jù, written with the same characters as 'renku') evolved in Chin-dynasty China, and it has been argued that this Chinese form influenced Japanese renga during its formative period.
Formats used in renku 
Below is a list of the formats most commonly used in writing renku
|Name of format||Number
|Number of kaishi
|Originator||Date of origin|
|Kasen (poetic geniuses)||36||2||4||unknown||1423|
|Han-kasen (half-kasen)||18||1||2||unknown||17th century|
- Crowley, Cheryl, translator of Horikiri Minoru. "Exploring Bashō's World of Poetic Expression: Soundscape Haiku" in Kerkham, Eleanor, editor. Matsuo Bashō's Poetic Spaces: Exploring Haikai Intersections. Palgrave Macmillan, 2006. ISBN 9781403972583 p159
- Sato, Hiroaki. One Hundred Frogs: from renga to haiku to English, Weatherhill 1983, ISBN 0-8348-0176-0 p.53
- Keene, Donald 1999. World Within Walls: A History of Japanese Literature, Vol. 2 New York: Columbia University Press. p16
- Reckert, Stephen, Beyond Chrysanthemums: Perspectives on Poetry East and West, Oxford University Press, 1993, ISBN 0-19-815165-9, p.43
- Sato, 1983, p.11
See also 
- Renga - the earlier collaborative poetry from which renku evolved
- Renshi, modern development of renga and renku
- Collaborative poetry
- Kigo - a season word or phrase used in many renku verses
- Matsuo Bashō - the 17th-century Japanese poet who brought renku to a pinnacle of artistic achievement
- Winter Days - a 2003 animated film, based on one of the renku in the collection of the same name by the 17th-century Japanese poet Bashō
- Haikai - the genre which encompasses renku and related forms such as haiku, senryū, haiga and haibun
- List of Japanese poetry anthologies