It is said that spring couplets originated from Tao Fu (some say its "peach wood charms," another says it's a regular board made of cherry wood, even others say it's written or carved on walnuts wood board!) with door gods painted on wood charms in earlier times.
As for the origination date, some people say it's during the Five Dynasties (907-960), the Emperor Meng Chang inscribed an inspiring couplet on a peach slat. But other says, during the Tang Dynasty, the use of tao fu has gradually disappeared and was replaced by two rows of corresponding couplets each written on a piece of red rectangular paper. Others hold that during Song dynasty, people started to use red paper for New Year couplets.
But all agree that Spring Couplets are mounted on either side of the door, and GRADUALLY evolved into today's popular custom of displaying spring couplets and propitious words, which has some connections with the couplets in meaning, across the lintel at the top.
In China, scholars would set up the tools and compose auspicious couplets for friends, relatives, and the publics. Spring Couplets are written on red paper, because red is a very lucky colour for the Chinese, it frightens off the New Year monster 'Nian' who arrives at this time of year and destroys crops and homes. "Nian" has three weaknesses: it was frightened by noise, sunshine, and the colour red. So villagers built fires, set off firecrackers, and painted the doors to their houses red and placed red couplets beside the doors. Red to the Chinese also represents good fortune, fame and riches.
A couplet is made up of two lines of verse which are called the "head" and "tail", which should correspond with each other phonologically and syntactically word for word and phrase for phrase. In the past time, children would be given this kind of test or practice.
Chinese people have a lot of different kinds of spring couplets. For businessmen, they will have special words for earning more money, and gain good reputation around the world. For usual families, they would get some for good fortune and luck.
Others reflect more recent concerns. For example, the CCTV New Year Gala usually promotes couplets reflecting current political themes in mainland China.
In the past, when the Son of Heaven, or Emperor died, for a whole year it is illegal to renew red spring couplets, together with other prohibitions, no marriage, no congratulations of childbirth which means no red eggs for the lucky parents, no joyous feast and merrymakings of all kinds, no gaudy head ornaments for women who are