The Twelve animals ("twelve birth emblems" or colloquially "twelve signs of belonging") representing the twelve Earthly Branches are, in order, the rat, ox, tiger, rabbit, dragon, snake, horse, sheep (or goat), monkey, rooster, dog, and pig (or boar).

In correlative thinking, the twelve years of the Jupiter cycle also identify the twelve months of the year, twelve animals (mnemonics for the system), directions, seasons, months, and Chinese hour in the form of double-hours. When a Branch is used for a double hour, the listed periods are meant. When used for an exact time of a day, it is the center of the period. For instance, 午 (the Horse) means noon or a period from 11am to 1pm.

Within the Heavenly Stems system the year is advanced up by one per year, cycling back to year one after the last (year ten). Similarly the Earthly Branches also advances by one per year, cyclically. Since the numbers 10 (Heavenly Stems) and 12 (Earthly Branches) have a common factor of 2, only 1/2 of the 120 possible stem-branch combinations actually occur. The resulting 60-year cycle takes the name jiǎzǐ (甲子) after the first year in the cycle, being the Heavenly Stem of jiǎ and Earthly Branch of zǐ. The term "jiǎzǐ" is used figuratively to mean "a full lifespan"—one who has lived more than a jiǎzǐ is obviously blessed. (Compare the Biblical "three-score years and ten.")

Around the Han Dynasty, the stem-branch cycle began to be used to mark years. The 60-year system cycles continuously, and determines the animal or sign under which a person is born. These cycles were not named, and were used in conjunction with regnal names declared by the Emperor. For example: 康熙壬寅 (Kāngxī rényín) (1662 AD) is the first 壬寅 (rényín) year during the reign of 康熙 (Kāngxī), regnal name of an emperor of the Qing Dynasty

The months and hours can also be denoted using Heavenly Stems and Earthly Branches, though they are commonly addressed using Chinese numerals instead.

From 1949 to 2009, China has experienced 60 years, which is called a Jiazi (甲子).Besides, this year is the year of Ox which represents energy and good luck. Therefore, we wish our motherland prosperous forever!

By Yan Fei