Quatrains are the shortest form of poetry in China literature. The five-character quatrain (hereinafter referred to as the five-character quatrain) has only 20 words, and the seven-character quatrain (hereinafter referred to as the seven-character quatrain) has only 28 words. Although there are not many words in quatrains, like metrical poems, words and other literary forms, they have left many classic works that have been sung through the ages.

The quatrains have the following characteristics in form:

1, definitely. Five verses are five words per sentence, and seven verses are seven words per sentence.

2. Fixed words. Five musts and seven musts are four sentences in each capital letter.

3. Rhyme. The second sentence of the quatrain and the last sentence of the fourth sentence must rhyme, and the last word of the first sentence can rhyme but not rhyme. The rhyme feet of metrical quatrains (hereinafter referred to as metrical quatrains) must be flat, and the rhyme feet of archaic quatrains (hereinafter referred to as archaic quatrains) can be flat or rhyming.

4. Law. The law must follow the rules of metrical rules, but it was not necessary in ancient times.