Celestial stem

Celestial stem (Chinese: 天干; pinyin: tiāngān) is an ancient Chinese cyclic character numeral system: Jia (甲), Yi (乙), Bing (丙), Ding (丁), Wu (戊), Ji (己), Geng (庚), Xin (辛), Ren (壬), Gui (癸). They were first used for dates in the Shang Dynasty, and are now used with the twelve Earthly Branches in the Sexagesimal cycle in the Chinese calendar and in Chinese astrology. They are associated with the concepts of yin and yang and the Five Elements.

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Origin

The Shang people had a myth in which there were ten suns, each of which appears in order in a ten-day cycle (旬; xǔn). The Heavenly Stems were the names of the ten suns. The kings of the Shang had characters of the Stems in their given names. Some historians think the ruling class of the Shang had ten clans, but it is not clear whether their society reflected the myth or vice versa. The association to Yin Yang and the Five Elements occurred later, after the collapse of the Shang Dynasty.

The literal meaning of the characters was roughly as follows:^[1]

Current usage

The Stems are still commonly used nowadays in China in counting systems similar to the way the alphabet is used in English, namely,

• Students' grades: with an additional Yōu (優 "Excellence") before Jiǎ.
• Names in legal documents and contracts where English speakers would use A, B, C, etc.
• Choices on multiple choice exams, surveys, etc.
• Naming of organic chemicals (e.g. methanol: 甲醇 jiǎchún; ethanol: 乙醇 yǐchún)
• Naming of diseases (Hepatitis A: 甲型肝炎 jiǎxíng gānyán; Hepatitis B: 乙型肝炎 yǐxíng gānyán)
• Naming of sports leagues (Serie A: 意甲 yìjiǎ)
• Vitamins' names (although currently, in this case, the ABC system is more popular)
• Naming characters entertaining a dialogue in a short text (甲 speaks first, 乙 answers)

Korea and Japan also use heavenly stems on legal documents in this way. In Korea, letters gap (甲) and eul (乙) are consistently used to denote the larger and the smaller contractor (respectively) in a legal contract, and are sometimes used as synonyms for such; such usage is common among Korean IT folks.

See also

• Chinese numerals

Notes

1. ^ William McNaughton. Reading and Writing Chinese. Tokyo: Charles E. Tuttle, 1979.