This brief techical description is derived from a posting by Denis Garrison, on July 6, 2001, to the WHC Shortverses list.

      This new form, this haiku analogue, is named the "crystalline" because the core value of the form is the highly condensed and concrete imagery of the couplet, transparent in its accessibility. On the first level, the technical criteria are really very simple. I have said of crystallines that writing them is like weight-lifting: technically simple, but hard to do well.

      The hard part, the fun part, the real art, is developing a good ear for a euphonious verse. Nothing works here except practice. Of course, for those of you who are already accomplished poets and have highly developed ears for a pleasingly modulated line, the challenge may be simply in fitting a lovely line to this strict form. When all the technique is second-nature, and the knack of writing in the haiku tradition, but in natural English diction, is yours, I expect and hope you will see crystallines as a viable western analogue of the classical haiku. Here is a simple listing of technical criteria:

      - A crystalline is a couplet, either regular (8/9 or 9/8 syllables) or irregular (5/12 to 12/5 syllables maximum range).

      - The couplet may be rhymed or unrhymed; in any case, do not force rhymes.

      - The couplet should consist in one or two sentences with normative initial capitalization and terminal punctuation.

      - The couplet must have exactly seventeen syllables, with deference granted the poet for dialectical variations.

      - An essential is natural English diction, carefully modulated for euphony.

      - The function of kireji (cutting words) is served by the line break.

      - Use of kigo (seasonwords, keywords, etc.) is encouraged but is not prerequisite.

      - Traditional English poetic devices (e.g., metaphor, simile, alliteration, assonance, consonance, onomatopoeia, allusion, rhyme) are permissible.

      - The harmony or beauty of sound, i.e., euphony, is more important than strict metrics. Skillful word selection to modify the rhythmic pattern, i.e., modulation, is highly desirable.

      - Crystallines may be linked by one poet or by more than one poet.

      - The fundamental difference from traditional haiku is that, while traditional haiku value direct observation with the greatest possible degree of non-subjectivity, subjectivity is permissible in a crystalline. The poet's response to the object and the poet's thoughts and feelings are admissible.

      - The haiku traditions of natural subjects and of objective imagery / the "objective correlative" are highly valued, albeit not enforced.