Hokku is the opening stanza of a Japanese orthodox collaborative linked poem, renga, or of its later derivative, renku. From the time of Matsuo Bashō, the hokku began to appear as an independent poem, and was also incorporated in haibun. In the late 19th century, Masaoka Shiki renamed the standalone hokku as "haiku", and the latter term is now generally applied retrospectively to all hokkuappearing independently of renku or renga, irrespective of when they were written. The term hokku continues to be used in its original sense, as the opening verse of a linked poem.
Content
Within the traditions of renga and renku, the hokku, as the opening verse of the poem, has always held a special position. It was traditional for the most honoured guest at the poetry-writing session to be invited to compose it, and he would be expected to offer praise to his host and/or deprecate himself, while superficially referring to current surroundings and season..
Form
Typically, a hokku is 17 moras in length, composed of three metrical units of 5, 7 and 5 morae respectively. Alone among the verses of a poem, the hokku includes a kireji or "cutting-word" that appears at the end of one of its three metrical units. Like all of the other stanzas, a Japanese hokku is traditionally written in a single vertical line.
Paralleling the development of haiku in English, poets writing renku in English nowadays seldom adhere to a 5-7-5 syllable format for the hokku, or other chōku, of their poem. The salutative requirement of the traditional hokku is often disregarded, but the hokku is still typically required to include a kigo, and to reflect the poet's current environment.
Example
Bashō composed the following hokku in 1689 during his journey through Oku, while writing renku in the house of a station master in Sukagawa at the entrance to Michinoku, in present-day Fukushima: Hearing the rice-planting songs in the fields, Bashō composed a poem that complimented the hoston the elegance of his home and region—which he associated with the historical "beginnings" of fūryū or poetic art—while suggesting his joy and gratitude at being able to compose linked verse or "poetry" for the "first time" in the Interior.