Haiku
Haiku, is a form of Japanese poetry, consisting of 17 moras (or on), in three phrases of 5, 7, and 5 moras respectively. Although haiku are often stated to have 17 syllables, this is inaccurate as syllables and moras are not the same. Haiku... typically contain a kigo (seasonal reference), and a kireji (cutting word). In Japanese, haiku are traditionally printed in a single vertical line and tend to take aspects of the natural world as their subject matter, while haiku in English often appear in three lines to parallel the three phrases of Japanese haiku and may deal with any subject matter. Previously called hokku, haiku was given its current name by the Japanese writer Masaoka Shiki at the end of the 19th century.
In contrast to English verse typically characterized by meter, Japanese verse counts sound units (moras), known as "on". Traditional haiku consist of 17 on, in three phrases of five, seven, and five on, respectively.
Although the word "on" is often translated as "syllable", in fact one on is counted for a short syllable, an additional one for an elongated vowel, diphthong, or doubled consonant, and one more for an "n" at the end of a syllable. Thus, the word "haibun", though counted as two syllables in English, is counted as four on in Japanese (ha-i-bu-n). This is illustrated by the Issa haiku below, which contains 17 on but only 15 syllables. In addition, some sounds, such as "kyo" can be perceived as two syllables in English but as a single on in Japanese. A word that illustrates both these issues is "Tokyo" , which is perceived as having three syllables in English (To-ky-o) but four moras in Japanese (To-u-kyo-u).
The word onji ("sound symbol") is sometimes used in referring to Japanese sound units in Englishalthough this word is no longer current in Japanese. In Japanese, each on corresponds to a kana character (or sometimes digraph) and hence ji (or "character") is also sometimes used as the count unit.
In 1973, the Haiku Society of America noted that the then norm for writers of haiku in English was to use 17 syllables, but they also noted a trend toward shorter haiku.] This trend is borne out by the winter 2010 edition of Frogpond, which contains haiku with an average of 10.5 syllables, varying from six at the shortest to 15 at the longest.