When did the Spring Festival couplets begin?

The knowledge about posting Spring Festival couplets is as follows:

1, the word at the end of the uplink should be "Cue". It is the "three tones" or "four tones" in modern Chinese. The sound of "Xu" gives the impression that the words have not been finished. The word at the end of the next couplet should be "Ping". It is the "one sound" or "two sounds" in modern Chinese. The sound of "ping" gives people the feeling that words are finished.

2. The number of words in Spring Festival couplets should be equal and the sentences should be consistent. In addition to deliberately leaving the position of a word to achieve a certain effect, the number of words in the upper and lower parts must be the same.

According to historical records, Zhu Yuanzhang of Ming Taizu loves couplets. He not only writes by himself, but also often encourages his officials to write.

4. After the Spring Festival couplets are pasted, they will be ignored, and the Spring Festival couplets will be hit by wind and rain and naturally fall off. Or see the Spring Festival couplets ruined by wind and rain, just take them off.

5. Because Spring Festival couplets are divided into upper couplets and lower couplets based on "pairs", they should be posted from right to left, the upper couplets should be posted from right, and the lower couplets should not be posted downward. The reason for posting this way is that the straight writing is from right to left, so reading couplets is also from right to left.