Quatrains, also called truncated sentences, broken sentences and quatrains, are short and pithy. It is a popular genre of Chinese poetry in the Tang Dynasty and belongs to a form of modern poetry. The word quatrains first appeared in the Qi and Liang Dynasties in the Southern Dynasties. There are four five-character and four-sentence poems in Chen's Poem on Yutai. I don't know the author's name, and the topic is "Ancient Jueju". At this time, quatrains refer to small poems with five words, four sentences and two rhymes, and do not require balance and harmony. Jue means "cut off", and the ancients used four poems with four quatrains to complete an ideological concept. There are two types of quatrains: quatrains and archaic styles. Rhythm only needs to be refined after the rise of rhythmic poetry. Ancient times existed long before the appearance of metrical poems.
The metrical requirements of metrical poems are various. First of all, the number of words in a poem is required to be uniform. Each poem has five words, six words or seven words, which are called five laws, six laws and seven laws for short, among which six laws are rare. Secondly, there are different restrictions on the number of poems, and the usual metrical poems stipulate eight sentences each. If there are only six sentences, it is called a small law or a three-rhyme poem; A metrical poem with more than eight sentences, that is, more than ten sentences, is called a unique law or a long law. The third is the specific dual requirements. Usually eight sentences are used to complete a poem, and every two sentences are connected into a couplet, which counts as four sentences. According to the structure of the old rhyme writing, it is customary to call the first couplet a title, the second couplet a parallel poem, the third couplet a neck couplet and the fourth couplet a sentence. The two couplets in the middle of each song, that is, the upper and lower sentences of parallel couplets and neck couplets, must be antithetical sentences. Except for the first two couplets, exclusion is not external, and the couplets in the middle must be dual. The infinitesimal duality requires a wide range, or one or two pairs, or two or three pairs, or only two pairs require dual sentences. The fourth is to strictly demand rhyme and meter. Take the commonly used five laws and seven laws as examples. The first is rhyme, which requires the whole poem to rhyme, and the rhyme is limited; The second, fourth, sixth and eighth sentences rhyme, and the first sentence can be taken or not. Most of the first sentences of the five laws don't rhyme, and most of the first sentences of the seven laws rhyme. There are rhymes, some people think that rhymes should belong to the ancient style. Second is the tone. Ancient Chinese is divided into four tones. The tone of poetry is flat and flat, and the above three tones are the same, which is called "promoting sound" Every sentence in metrical poems is flat and even, while the flat and even words in the upper and lower sentences are opposite, and there are two types of flat and even words.