Why write eight-character couplets?

In traditional culture, couplets are generally odd numbers, and it is ok to use eight words for couplets. As long as the words are harmonious, the rhythm is harmonious and the meaning of couplets is positive.

Couplets require that the number of words in the upper and lower couplets should be equal, the phrases should be the same, the parts of speech should be the same, and the grammatical structure of the corresponding sentences should be the same as much as possible, and even words should be in tune. Words with repeated meanings are called "crossing hands" in the terminology of couplets, which is taboo-after all, the number of words in couplets is limited, and pen and ink must not be wasted.

Couplets are antithetical sentences written on paper or cloth or engraved on bamboo, wood or columns. It is a unique art form of Chinese language, which is concise and profound, neat and even, with the same number of words and the same structure