he time the beginning of a calendar year was about one or two months after the winter solstice. Take a particular winter solstice as a reference time. Let N be the number of years between this winter solstice and the superior epoch, <span class="nowrap">R<sub>0</sub></span> be the number of years between the reference year and the previous ji&#462; z&#464; year, <span class="nowrap">r<sub>1</sub></span> be the number of days between this winter solstice and midnight on the previous ji&#462; z&#464; day, and