Parallelism emphasizing thesis or antithesis is frequently found but is not an obligatory feature.

[1] Gushi poems first really began to emerge as a poetic form in the second century CE.

[2] In its subsequent history, a revival during the Tang dynasty produced an additional period of flourishing for this form of poetry.

[3] These nineteen poems are generally characterized as rhymed verse, in the five-character line, unregulated style.

In the Tang dynasty, with the development of the new style poetry (jintishi), also known as regulated verse, the term gushi was applied to poetry which did not necessarily keep under restriction the length of the poem nor to fulfill requirements for verbal or tonal parallelisms: in the freer gushi form of verse, often various rules were pointedly violated, such as by the use of unusual rhyme schemes or conspicuous avoidance of verbal parallelism.