Haiku is a type of short-form poetry that originated in Japan. Traditional Japanese haiku consist of three phrases composed of 17 morae in a 5, 7, 5 pattern that include a kireji or "cutting word" and a kigo or seasonal reference. However, haiku by classical Japanese poets, such as Matsuo Bashō, also deviate from the 17-on pattern and sometimes do not contain a kireji. Similar poems that do not adhere to these rules are generally classified as senryū.