更点制出现的年代较早,但是明确见诸历法者,似以唐初《戊寅元历》与《麟德历》为嚆矢。《戊寅元历》最后附录的“二十四气日出入时刻表”中,给出了各气昼、夜漏刻的长度以及相应的更点数。由该表所列数据,可以很容易地得出如下结论:第一,日出前2.5刻为平旦时刻,即昼漏上水时刻;日人后2.5刻为昏时,即昼漏尽、夜漏初上时刻。从昏时至次日旦时,为夜漏长度。第二,l更=夜漏刻/5,1筹=夜漏刻/25.l筹即一点,亦称一唱、一鼓等。以上两条推断与历史文献中有关更点制度的纪录 More system appeared earlier, but clearly see the calendars, like the early Tang Dynasty “Yiyin” and “Lin ambition” as the arrow vector. In the final appendix of “Yiyin”, “the twenty-four gas daily arrival schedule” shows the lengths of the diurnal days and the missed leaks and the corresponding more points. From the data listed in this table, we can easily draw the following conclusions: First, 2.5 minutes before sunrise is a flattened moment, that is, the daylight falls on the water moment; Leak at the beginning of the moment. From fainting to the next day, the length of night-leakage. Second, l more = night leak moment / 5,1 chip = night missed moment / 251.l chip that is a bit, also known as a sing, a drum and so on. The above two inferred historical records in relation to more system