Metre (poetry) of over some two-and-a-half millennia. Beginning with the earlier recorded forms: the Classic of Poetry tends toward couplets of four-character lines, grouped in rhymed quatrains; and, the Chuci follows this to some extent, but moves toward variations in line length. Han Dynasty poetry tended towards the variable line-length forms of the folk ballads and the Music Bureau yuefu. Jian'an poetry, Six Dynasties poetry, and Tang Dynasty poetry tend towards a poetic metre based on fixed-length lines of five, seven, (or, more rarely six) characters/verbal units tended to predominate, generally in couplet/quatrain-based forms, of various total verse lengths. The Song poetry
Decasyllabic quatrain decasyllabic quatrain contains a stiffness that can not be overcome: You can not vary your stops, as in blank verse or the Spenserian, there is not room enough: and the recurrent divisions necessatated by the stanza lack at once the conciseness and the continuity of the couplet, the variety and amplitude of the rhyme-royal, octave, or Spenserian itself. In his essay on "Annus Mirabilis", A. W. Ward suggests that the decasyllabic quatrain used by Davenant and Dryden, with its insistence on providing each quatrain with the "completeness" given by the final period, causes the verse to strike the reader as