Heavenly Stems and Earthly Branches(天干地支):
In Chinese, it is pronounced as: tiān gān dì zhī，Written as:

Heavenly Stems and Earthly Branches is an ancient Chinese method used for reckoning years, months, days, and hours. It consists of two parts: the Heavenly Stems and the Earthly Branches, together forming a cycle of 60 combinations known as the “Sixty Jiazi.” There are ten Heavenly Stems and twelve Earthly Branches. They are as follows:
Heavenly Stems: Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui.
Earthly Branches: Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai.
Pronunciations of Heavenly Stems and Earthly Branches in Chinese:
Heavenly Stems: Jia (jiǎ), Yi (yǐ), Bing (bǐng), Ding (dīng), Wu (wù), Ji (jǐ), Geng (gēng), Xin (xīn), Ren (rén), Gui (guǐ).
Earthly Branches: Zi (zǐ), Chou (chǒu), Yin (yín), Mao (mǎo), Chen (chén), Si (sì), Wu (wǔ), Wei (wèi), Shen (shēn), You (yǒu), Xu (xū), Hai (hài).
Heavenly Stems and Earthly Branches are not only a method of calendrical notation but also carry the ancient Chinese understanding of the cosmic and terrestrial laws. The Heavenly Stems represent the “Way of Heaven,” while the Earthly Branches represent the “Way of Earth.” Together, they elucidate the principles governing the cosmos and human affairs. The combination of the Heavenly Stems and Earthly Branches forms sixty basic units used to mark years, months, days, and hours, reflecting ancient China’s understanding and application of space and time.