But people couldn't be so casual for important matters, like weddings, funerals, and ground-breaking, or for determining a time of birth (which was essential for a correct horoscope reading). They had to know the exact time of day.
日出而作，日入而息的平常日子也罷了，遇到需要算時辰的大事，像是婚喪、開工、動土，以及計算出生嬰兒的生辰八字，可就不能馬馬虎虎。