The 10 Heavenly Stems

The Ten Heavenly or Celestial Stems (天干) are the elements of 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), Kui (癸).

They are associated with the concepts of Yin and Yang and the Five Elements. They have either Yin or Yang properties as well as elemental property of the Five elements.The heavenly stems are the prevailing energy (Qi) or surface Qi.

The 10 heavenly stems are some of the oldest Chinese characters known.  Their first recorded use seems to be during the 商 Shāng dynasty, around 1500 BC, where they appeared on oracle bones.  These ‘oracle bones’ were usually the scapula of oxen or tortoise plastrons that were drilled with small holes then subjected to fire to form many tiny cracks, the relative auspiciousness (or inauspiciousness) of which could be read by a skilled diviner.

The philosophy of the heavenly stems was developed over time and recorded in ancient classical texts.  They were adopted to describe the circulation of the Qi of the five elements in the sky. 

Evolution of the stems continued and scholars classified the odd numbered as yang, the even as yin. 

Odd number : Jia (甲), Bing (丙), Wu (戊), Geng (庚), Ren (壬) are classified as Yang

Even number : Yi (乙), Ding (丁), Ji (己), Xin (辛), Kui (癸) are classified as Yin

They then combined with the earthly branches (yin to yin and yang to yang) to make up the earthly branches (干支 Gānzhī or 甲子 Jiǎzǐ - named after 1st combination) the ‘60 binomials’. 

In BaZi reading (子平Zǐpíng method), the heavenly stems represent the upper layers of interpretation of a chart. They are external perceptions of a person in terms of character, personality or outlook in life. They are insights into a person’s character, potential and destiny by their appearance in a BaZi Chart.