B when is it?

From 23: 00 am to 1 o'clock, from 3: 00 am to 3: 00 am, from 3: 00 pm to 5: 00 pm, from 5: 00 am to 7: 00 am, from 9: 00 am to 1 o'clock,13 pm. Unitary time is 17 to 19, time is 19 to 2 1, and time is 2 1 to 23.

In ancient times, day and night were divided into twelve hours, that is, one hour was equivalent to two hours, and the corresponding relationship between twelve hours and twenty-four hours was from 5 o'clock to 7 o'clock. Starting from Jiazi Day, the main branches of this day are Jiazi, Ugly B and Bingyin, and Ugly B is Bingzi, Ugly D, Wuyin and Jimao, and the cycle is carried out according to 60 Jiazi.

Shi Mao, sunrise, also known as the beginning of the day, dawn, sunrise and so on. It refers to the time when the sun just appeared and Ran Ran first rose from 5: 00 to 7: 00. In ancient times, this was the time when official institutions started to work, so it was also called calling. Because it coincides with the sunrise in Ran Ran, it is also called sunrise.

Twelve o'clock system was adopted in the Western Zhou Dynasty, and it was named midnight, crow, pingdan, sunrise, food time, corner, Japanese-Chinese, sundial, sunset, dusk and human decision in the Han Dynasty. It is also represented by the twelve earthly branches, when 23 o'clock to 1 point is the child time, 1 point to 3 o'clock is the ugly time, and 3 o'clock to 5 o'clock is the Yin Shi time, and recursively.