Ancient Chinese timekeeping can be summed up in one sentence: the day is carved with the chen, and the night is used by the more point system.
Gu Yanwu's Rizhilu: "From the Han Dynasty onwards. The calendar became denser, so that the day was divided into twelve hours, and the cover did not know who it began with, but it has not been abolished. ”
Chen: In ancient times, a day was divided into 12 hours, using the earth branch as the name, namely: zi, ugly, yin, 卯, 辰, 巳, 巳, noon, wei, Shen, unitary, 戌, 海. During the Northern Song Dynasty, each hour was divided into two parts, "beginning" and "positive", divided into twelve hours for twenty-four hours, called "hours".
Gu Yanwu
Engraving: Before the Western Zhou Dynasty, the ancients divided a day and night into 100 engravings, which were converted into modern chronograph units, and 1 engraving was equal to 14 minutes and 24 seconds. The "Hundred Carving System" is the oldest and longest-used chronograph system on the mainland. In the Qing Dynasty, it was officially stipulated that a day and night should be 96 minutes, and each hour was eight minutes, which was divided into the upper four and the next four.
More: The duty personnel in the Han Dynasty Imperial Palace were divided into five shifts and replaced on time, called "five more". It is one more when it is dark, two times more in the hour, three more when it is sub-time, four more when it is ugly, and five more when it is ugly.
Points: One more is divided into five points, and the length of one point is 24 minutes. "Three more two o'clock" refers to 11:48 p.m.; "five drums and three o'clock" refers to 04:12 a.m.