Kireji

Kireji (切れ字, lit. "cutting word"^?) is the term for a special category of words used in certain types of Japanese traditional poetry. It is regarded as a requirement in traditional haiku, as well as in the hokku, or opening verse, of both classical renga and its derivative renku (haikai no renga). There is no exact equivalent of kireji in English, and its function can be difficult to define. It is said to supply structural support to the verse. When placed at the end of a verse, it provides a dignified ending, concluding the verse with a heightened sense of closure. Used in the middle of a verse, it briefly cuts the stream of thought, indicating that the verse consists of two thoughts half independent of each other. In such a position, it indicates a pause, both rhythmically and grammatically, and may lend an emotional flavour to the phrase preceding it.

Classical renga developed a tradition of 18 kireji, which were adopted by haikai, thence used for both renku and haiku, the most common of which are listed below:

Hokku and haiku consist of 17 Japanese syllables, or on (a phonetic unit identical to the mora), in three metrical phrases of 5, 7, and 5 on respectively. A kireji is typically positioned at the end of one of these three phrases. When it is placed at the end of the final phrase (i.e. the end of the verse), the kireji draws the reader back to the beginning, initiating a circular pattern. A large number of hokku, including many of those by Bashō, end with either -keri, an exclamatory auxiliary verb, or the exclamatory particle kana, both of which initiate such a circular pattern. Placed elsewhere in the verse, a kireji performs the paradoxical function of both cutting and joining; it not only cuts the ku into two parts, but also establishes a correspondence between the two images it separates, implying that the latter represents the poetic essence (本意 hon'i) of the former, creating two centres and often generating an implicit comparison, equation, or contrast between the two separate elements

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