the ten Heavenly Stems (甲 jiǎ, 乙 yǐ, 丙 bǐng, 丁 dīng, 戊 wù, 己 jǐ, 庚 gēng, 辛 xīn, 壬 rén, 癸 guǐ), used cyclically in the traditional Chinese calendar and as ordinal numbers

古代人用十天干和十二地支来记录日期。