Senryū

Senryū (川柳^?, literally 'river willow') is a Japanese form of short poetry similar to haiku in construction: three lines with 17 morae (or "on", often translated as syllables, but see the article on onji for distinctions). Senryū tend to be about human foibles while haiku tend to be about nature, and senryū are often cynical or darkly humorous while haiku are more serious. Unlike haiku, senryū do not include a kireji (cutting word), and do not generally include a kigo, or season word.

Senryū is named after Edo period haikai poet Senryū Karai (柄井川柳, 1718-1790), whose collection Haifūyanagidaru (誹風柳多留^?) launched the genre into the public consciousness. A typical example from the collection:

泥棒を dorobō o
捕えてみれば toraete mireba
我が子なり wagako nari

When I catch,
The robber,
my own son

This senryū, which can also be translated "Catching him / you see the robber / is your son," is not so much a personal experience of the author as an example of a type of situation (provided by a short comment called a maeku or fore-verse, which usually prefaces a number of examples) and/or a brief or witty rendition of an incident from history or the arts (plays, songs, tales, poetry, etc.). In this case, there was a historical incident of legendary proportion.

...
Wikipedia