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
Accentual-syllabic verse Accentual-syllabic verse Accentual-syllabic verse is an extension of accentual verse which fixes both the number of stresses and syllables within a line or stanza. Accentual-syllabic verse is highly regular and therefore easily scannable. Usually, either one metrical foot, or a specific pattern of metrical feet, is used throughout the entire poem; thus we can talk about a poem being in, for example, iambic pentameter. Poets naturally vary the rhythm of their lines, using devices such as inversion, elision, masculine and feminine endings, the caesura, using secondary stress, the addition of extra-metrical syllables, or the omission of syllables, the substitution of