Chapter 39 Section 4: Coordination of the 12-hour system and the omission system

It has been used for quite a long time to engrave the independent period, and this method has been used throughout the Northern and Southern Dynasties.However, dividing a day and night into 12 quarters is relatively thick, and dividing a day and night into 100 quarters is too short. If the two are combined to form a system, it will be very appropriate.The ancients had thought of this problem a long time ago. In order to make the two can be combined concisely, Xia Heliang once suggested abolishing the 100-cut system and switching to 120-cut system when Emperor Ai of the Western Han Dynasty. Emperor Wu of Liang used 96 engravings first, and then changed to 108 engravings. However, because the hundred engravings have been used for a long time, the long-standing habit is hard to change, so the desire to combine the two has not been realized.

Regarding the coordination of the twelve-hour system and the hundred-time system, in the Sui and Tang Dynasties, people no longer considered changing the hundred-time system to achieve it, but recognized the fait accompli and coordinated the two.At the beginning, it was proposed that Zi, Wu, Mao, and You each had nine quarters, and the remaining eight quarters.It was also proposed that Zi and Wu each have ten quarters, and the remaining eight quarters.However, these two opinions have changed the rule of equal division of twelve hours, which cannot be accepted by people.In the end, only the method of equal division can be used.

The specific method is to divide the hundred engravings into twelve equal parts, and add 1/6 engraving to the eight major engravings for each hour, and this 1/6 is also called the small engraving. This is how the ancients unified the two.After dividing an hour into two parts, people divide an hour into [four and one-sixth] quarters, and this 1/6 quarter is also called a small quarter.After this regulation was made, when people calculate the time, they will use a certain moment to express it uniformly. On the scale of the arrow and armillary sphere, the twelve o'clock and the hundred quarters will also be used together. Small engraved.