Senryu is similar to a haiku, but focuses more on human nature in a humorous or satirical way.
Haibun is autobiographical prose with haiku, where the poem links to the prose, but at the same time shifts away from it, adding another layer of reflection.
Rengay is a six-verse poem, written by two or three writers, with a set pattern of three-line and two-line haiku. All six poems have at least one unifying theme. A theme is the most important characteristic of rengay.