The number of words in a metrical poem is uniform, and each sentence is five or seven words, which are called five-word metrical poem and seven-word metrical poem respectively. The five laws stipulate that every sentence has five words, and the first word is forty words; Seven laws stipulate seven words for each sentence and fifty-six words for the whole sentence. There are also six-character sentences, all of which begin with 48 characters. They are called six-character poems, and there are few handed down works.
Rhyme is a genre of China's traditional poetry, which belongs to the category of modern poetry. Named for its strict metrical requirements. Metric poems originated from Shen Yue and other new-style poems that emphasized the antithesis of metrical poems in the Southern Dynasties, and further developed and stereotyped in the early Tang Dynasty and Song Dynasty, and prevailed in the Tang and Song Dynasties. Rhyme has strict rules in word, rhyme, even tone and antithesis. Its common types are five-character poems and seven-character poems.