Sheng in Chinese is "birth" and xiao is "resernblance". To discuss about the Sheng Xiao of Chinese, it is better to say something about the chronological years recorded by Stems and Branches in the Chinese lunar calendar. As we know, the lunar calendar was already perfect over 3000 years ago during Xia Dynasty, so it was also called "Xia Calendar". In Xia Calendar, the chronoloical years were recorded on the basis of Stems and Branches, that is, on combining in successionone Heavenly Stem and one Earthly Branch The Heavenly Stems are10, namely Jia, Yi, Bing, Ding, Wu Ji Geng Xin Ren and Gui, and the Earthly Branches are 12, that is Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai.Combining one heavenly Stem with one Earthly Branch in succession will give Jia Zi, Yi Chou, Bing Yin-and so on to the sixtieth one, Gui Hai, to make up a set, which is generally known as "sixty Jia Zi". These are then matched to the chronological years, with 60 years as a cycle, and similar to years,months, and branches, so the records in the calendar on this basis would be very clear and in a goog order. The Chinese ancesters emphasized the unity of heaven and man. Human beings and all life in the nature were thought to be naturally associated, the universe was co-existing with us. and everything around was combined with us as unity. Hence, 12 animals were used to match 12 Earthly Branches, such as, Zi is rat, Chou is Ox...... In calculating years. for example,
any years with "Chen". such as Jia Chen, Bing Chen and so on, will be called the dragon years, and those born in the dragon years will belong to the Dragon. Later, the year one is born is thought to be related to his behavior, which will resemble that of the animal of the Earthly Branched, for example, those born in dragon years will resemble dragon.....
The 12 Sheng Xiao are then Zi Rat, Chou Ox, Yin Tiger, Mao Rabbit, Chen Dragon, Si Snake, Wu Horse, Wei Goat, Shen Monkey, You Chicken, Xu Dog and Hai Pig.