The Chinese era is the symbol that the Chinese calendar uses for recording and naming years. The ten Heavenly Stems are: jia, yi, bing, ding, wu, ji, geng, xin, ren, gui. The twelve Earthly Branches are: zi, chou, yin, mou, chen, si, wu, wei, shen, you, xu, hai. After observing the lunar month, the ancients found that the moon always waxes and wanes roughly 12 times a year, and two lunar months account for about 60 days. So the order of the ten Heavenly Stems and the order of the twelve Earthly Branches are properly matched in turn. In terms of recording date, 60 years is considered to be a full time cycle. The Chinese ear chronology was first invented in ancient times and is still in use now. According to the chronology of the “ten Heavenly Stems”, 2011 is the year of “the seventh of the ten Heavenly Stems” and “the fifth of the twelve Earthly Branches”.