Wuxu: wù xū.
Heavenly stems and earthly branches are simply called stems and branches. A, B, B, Ding, Wu, Ji, Geng, Xin, Ren and Gui are collectively called the Ten Heavenly Stems; Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai are called the Ten Heavenly Stems. Two earthly branches. The composition of the heavenly stems and earthly branches formed the ancient calendar. In folklore, it is believed that the heavenly stems correspond to some omens. The ten stems and twelve branches are matched in sequence to form sixty basic units, which also form a set of stem and branch disciplines. Judging from the oracle bone inscriptions unearthed at the Yin Ruins, the Heavenly Stems and Earthly Branches are mainly used in Chinese folk to record dates, divination, and record events. Later, they were also used in fields such as Feng Shui and numerology. The calendar in which the stems and branches are used to record years, months, days, and hours is called the Ganzhi Calendar.