At this time, the sun has set, the sky will be dark, the world will be dim, and everything is hazy, so it is called dusk. Time is an ancient unit of time. The ancients divided a day into twelve hours, and each hour is equal to two hours now.

The Western Zhou Dynasty used the twelve o'clock system, and the Han Dynasty named it Midnight, Cockcrow, Pingdan, Sunrise, Food Time, Corner, Japan-China, Sundial, Dawn, Dusk, and People's Decision. Represented by twelve earthly branches, when midnight is 23:00- 1:00, 1:00-3:00 is ugly, and 3:00-5:00 is Yin Shi, recursively.

Time origin:

At first, the ancient working people described the time mainly with reference to obvious astronomical phenomena, animal biological clocks and daily life, such as crow, pingdan, Chaoshi, Japan and China, and people's daily life. Later, they gradually used the readings of timing equipment to describe time, and later, they gradually used five elements to assign values to the readings of these timing equipment.

For example, the characters A and B match wood (4:48-9:36), C and D match fire (9:36- 14:24) and Wuji match soil (14: 24-19:/kloc). These parallel meetings have no practical significance.