What is Chinese era? Chinese era, also known as Stems-and Branches, is a cyclic numeral system of 60 combinations of the two basic cycles， the ten Heavenly Stems and the twelve Earthly Branches. The ten Heavenly Stems and the twelve Earthly Branches are sequenced and combined by a certain order. Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren and Gui are called the ten Heavenly Stems. Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai are called the twelve Earthly Branches. The ten Heavenly Stems is the result of the five elements of Yin and Yang that we are familiar with. The twelve Earthly Branches are the twelve zodiac signs that we are familiar with.
Heavenly Stems and Earthly Branches are abbreviated as the Stems-and-Branches, originated from Chinese ancestors’ observations of celestial phenomena in ancient China. As early as about 2700B.C.，the ancestor of the Chinese nation, Yellow Emperor(Huangdi) sent Da Nao Shi to create a calendar system. Da Nao Shi explored the rule of changes between heaven and earth as well as that of the four seasons. Then he created ten heavenly stems and twelve earthly branches to make combinations representing a sexagenary cycle. It appears as a means of designating days in the first Chinese written texts.
A year can be represented by the composition of the two characters, one from the heavenly set and one from the other. That is believed to be the start of the stem-branch calendar. The invention of the Chinese era has a far-reaching impact. Up to now, it is widely applied in calendar, divination, calculation, naming and other aspects in China.
