What are the requirements for writing couplets?

The basic requirements of couplets are: equal number of words, cohesion from top to bottom, phonology and relative part of speech matching.

1, the upper part and the lower part have the same number of words. There are many forms of couplets, such as positive, negative, flowing, couplet and definite sentence, but the invariable rule is that the number of words in the upper and lower couplets is equal. For example, the first part: Wan Daoxiang Guangteng Concubine, and the second part: Jiuzhong Spring Scenery Yinghuatang. You can see that the number of words in couplets is equal.

2. The upper part and the lower part should be connected up and down. The upper and lower couplets are connected with each other and have similar contents, but they cannot be repeated. For example, the first part: Castle Peak will not be painted for a thousand years, and the second part: flowing stringed guqin.