The stem-branch calendar system is a unique way of recording time in ancient China. Why does it form a 60-year cycle? Let's uncover this mystery together.

Rules of Stem-Branch Pairing

The stem-branch calendar system pairs heavenly stems with earthly branches, following the principle that yang matches yang and yin matches yin. This means that only stems and branches of the same nature can be combined, resulting in combinations like Jia Zi and Yi Chou, but not "Jia Chou" or "Yi Yin."

Why a 60-Year Cycle?

There are ten heavenly stems and twelve earthly branches. When paired according to their yin-yang attributes, each stem can only combine with half of the branches, reducing the number of possible combinations to 60. Therefore, the stem-branch calendar system forms a 60-year cycle, with each specific combination appearing once every 60 years.

History and Influence of the Stem-Branch Calendar

The stem-branch calendar system originated during the era of the Yellow Emperor, but it began to be used in the early Western Han Dynasty and became an official method of recording time during the Eastern Han Dynasty. It was not only used for recording historical events but also influenced Chinese culture and daily life, including fields such as agriculture, medicine, and fortune-telling. Through the stem-branch calendar system, we can understand how the ancients combined the theories of yin-yang and the five elements with astronomical observations to create an accurate and culturally significant system of time recording.

The 60-year cycle of the stem-branch calendar system demonstrates the wisdom of ancient Chinese people and allows us today to better understand and appreciate China's rich history and cultural heritage.