Evolved from hokku, the opening stanza of collaborative linked verse (renga and renku), elevated as standalone poetry by Matsuo Bashō (1644–1694) and renamed haiku by Masaoka Shiki (1867–1902).
Traditional Japanese haiku consist of 17 sound units (on, or morae) in three phrases of 5, 7, and 5 on, traditionally printed as a single vertical line in Japanese.
Pairs a seasonal reference word (kigo, drawn from a saijiki almanac) with a cutting word (kireji) that punctuates rhythm and juxtaposes two images.