How to calculate the ancient chronology

1. chronology of main branches

Dating method of one-to-one correspondence between "heavenly stems" and "earthly branches" Characterized in that:

A, heavenly stems and earthly branches each forms a Gregorian calendar year, such as "Jiazi Year" and "Renwu Year".

B, heavenly stems and earthly branches collocation is always singular to singular, even to even, it is impossible to even and odd combination.

C, 60-year cycle, cycle after cycle.

2. Year number and year

Since the reign of Emperor Wu of the Han Dynasty, emperors have had year numbers when they acceded to the throne, and then they used the year numbers to mark the years. Such as: the first year of Kangxi. The story of Yueyang Tower, celebrating the spring of the fourth year, traveling on the pipa, visiting Baochan Mountain for ten years in Yuanhe, in July of the first year of Yuanhe, in Yuanfeng of Shi Zhongshan for seven years, in Shunzhi of Meihualing for two years, in Deyou for two years, and in Nandao for two years.

Extended data

Ancient timing tools

1, standard table

The "table" in the standard table is a pole or stone pillar standing vertically on the ground; "Gui" is a slate extending horizontally from the heel of the watch to the north. Whenever the sun turns due south, the shadow falls on the water of Guiyu. By measuring the length of the shadow, we can calculate the time of each solar term such as winter solstice and summer solstice. When the shadow is the longest, the winter solstice is here; The shortest time, the summer solstice is coming. It is the oldest and most common astronomical instrument in China.

2, tick off leakage

Also known as clepsydra and clepsydra. There are two main types of clepsydra: drainage type and water receiving type. Most of the early water leaks were drainage type. The bottom side of the leaky kettle leaks water, and the grid fork and the closing tongue rise again, so that the leaking arrow floating on the surface of the leaky kettle drops with the water surface, and the scale on the leaking arrow indicates the time. Later, the water-receiving type was created. Water is injected from the leaky kettle into the receiving kettle at a constant flow rate, and the leaking arrow floating on the water surface of the receiving kettle indicates the time with the rise of the water surface, thus improving the timing accuracy.

3, hourglass

Because water freezes easily in winter, it is driven by quicksand. Tian Wenzhi of Shi Ming records that Zhan Xiyuan created the "five-wheel hourglass" in the early days. Later, in order to prevent congestion, Zhou Shuxue enlarged the quicksand cave and replaced it with six wheels. Song Lian (1310 ~1381) wrote "songji", which recorded the hourglass structure, with the size of parts and the number of teeth of each wheel of the reduction gear, and said that the shaft tip of the fifth wheel had no teeth, but it was equipped with a landscape disk indicating time.

Baidu encyclopedia-ancient chronology