Haiku

is a type of Japanese poetry. Previously called hokku, haiku was given its current name by the Japanese writer Masaoka Shiki at the end of the 19th century.
The traditional hokku usually was written in six verses or more or less 5, 7, 5 syllables and they had to follow (on-ji). The Japanese word cow, meaning "sound", corresponds to a mora, a phonetic unit similar but not identical to the syllable of a language such as English. A haiku has a special season word (the kigo) to represent the season in which the poem is set, or a reference to the natural world.
Haiku usually breaks in three parts, called kireji, normally placed at the end of the first five or second seven morae. In Japanese, there are actual kireji words. In English, kireji is often replaced with commas, hyphens, elipses, or breaks in the haiku. Japanese haiku are normally written in one line, while English language haiku are traditionally separated into three lines.
In Japanese, nouns do not have different singular and plural forms, so "haiku" is used as both a singular and plural noun in English as well.
Examples
Japanese hokku and haiku are traditionally printed in one vertical line.
An example of classic hokku by poet Basho:
Gu Chi yaWa Fei Ip muShui noYin
Furu ike ya kawazu tobikomu mizu no oto
An old pond
When the frogs jump in
The sound of water
Another haiku by Basho:
Chu shigureYuan moXiao Suo wohoshigeYe
Hatsu shigure saru mo komino wo hoshige nari
The first cold shower;
Even the monkey seems to want
A little coat of straw.
(Coats and straw hats were normally used in Japan to protect from rain at the time)
Famous writers
Pre-Shiki period (hokku)
Matsuo Basho (1644-1694)
Onitsura (1661-1738)
Yosa Buson (1716-1783)
Kobayashi Issa (1763-1827)
Shiki and later (haiku)
Masaoka Shiki (1867-1902)
Kawahigashi Hekigoto (1873-1937)
Takahama Kyoshi (1874-1959)
Taneda Santoka (1882-1940)
Iida Dakotsu (1885-1962)
Nakamura Kusatao (1901-1983)
Non-Japanese poets
All of the poets below have some haiku. However, only Hackett and Virgilio are known for writing haiku. Richard Wright wrote some 4000 haiku in the last eighteen months of his life. Amiri Baraka recently wrote a collection of what he calls "low coup." This is his own version of haiku. Poet Sonia Sanchez is also known for putting together haiku and the blues musical genre.
Jake Dalton
W. H. Auden
Amiri Baraka
Jorge Luis Borges
Billy Collins
Cid Corman
Allen Ginsberg
Nicolas Grenier
James W. Hackett
Dag Hammarskjold
Jack Kerouac
Lenard D. Moore
Octavio Paz
Jose Juan Tablada
Raymond Roseliep
Kenneth Rexroth
Sonia Sanchez
Edith Shiffert
Gary Snyder
Jose Juan Tablada
Nick-Kizzy-Virgilio
Gerald Vizenor
Richard Wright
Jane Reichold
Christos Dimitroulopoulos
Other websites
Haiku for You
"Aha! poetry" : Website with essays on and examples of haiku and related forms
"Daily Haiku by Wisteria Press": Website offering a free daily haiku via email
Haiku Society of America
Wonder Haiku Worlds: A community portal for haiku and related forms
In the moonlight a worm... : Ideas for teaching haiku writing that go beyond the syllable rule
Haiku for People - Haiku definitions and samples, online since 1995
Shiki Haikusphere and NOBO list
Spanish Haikus
"Young Leaves": Website of the Yuki Teikei Haiku Society showing the use of Japanese traditions in English-language haiku
"Versions" : International community of haiku and tanka translators
Haiku Society
Haiku poems at Irreferencias (spanish)
Random Haiku - random haikus with an API for your blog, myspace, Facebook profile
Hokku
Page on Yone Noguchi and hokku at Ehime University
David Coomler's blog with essays and information on hokku
Japanese literature
Poetry forms