Chinese use 10 Celestial Stems 天干[tiān gān] and 12 Terrestrial Branches 地支[dì zhī] to name, count and record the year, the month, the day, and the hour of time. The ancient Chinese believed that the earth was separated from heaven (sky), and then there are people. The heaven is to the earth as the trunk to the branch. Therefore, they took celestial stem and terrestrial branch in terms to count, symbolizes, and record the time. 天干地支[tiān gān dì zhī] can be abbreviated to "Stem and Branch" 干支[gān zhī]. Today, 干支[gān zhī] is still used in calendars, fortune-telling, sacrificial ceremony, counting, name giving, etc.
