Nomenclature of Chinese Calendar

The years are named by a cycle of 10 Heavenly Stems and a cycle of 12 Earthly Branches. Each year is named by a pair of one stem and one branch called a Stem-Branch (ganzhi). The Heavenly Stems are associated with Yin Yang and the Five Elements. Recent 10-year periods began in 1984, 1994, 2004, etc. Earthly Branches are associated with the Twelve Animals. Recent 12-year periods began in 1984, 1996, etc.

The 60-year cycle formed by combining the two cycles is known as a jiazi. It is not 120 because half of the combinations are unused. Jiǎzǐ is named after the first year in the 60-year cycle which is called jiazi. Some figures of speech use "jiazi" to mean "a full lifespan"—one who has lived more than a jiǎzǐ is obviously blessed. (Compare the Biblical "three-score years and ten.")

This 60-year cycle is insufficient for historical references. During the Imperial period, the Nian Hao (Era name of an emperor) was placed in front of the year name for distinction. Example:(kangxirenyin) (1662 AD) is the first(renyin) year during the reign of kangxi. Using a particular emperor's nian hao was implicit recognition of the legitimacy of that emperor which could be very politically significant in cases of disputed succession or revolt. In addition, it also made it difficult for Chinese historians to avoid taking sides over which dynasty was more legitimate in talking about earlier periods in which China was divided.

The months, days, and hours can also be denoted using Heavenly Stems and Earthly Branches, though they are commonly addressed using Chinese numerals instead. Together, four Stem-Branch pairs form the Eight Characters (bazi) used in Chinese astrology.

There is a distinction between a solar year and a lunar year in the Chinese calendar because the calendar is lunisolar. A lunar year (nian) is from one Chinese new year to the next. A solar year (sui) is either the period between one "start of spring" and the next or the period between two winter solstices (see Jiéqì section). A lunar year is exclusively used for dates, whereas a solar year, especially that between winter solstices, is used to number.