Twelve earthly branches: ugly Mao Yinchen has asked for an audience at noon.
Sixty jiazi: The most timely method is to combine the ten-day trunk with the twelve-day branch. There are sixty combinations. The first combination is Jiazi. Cycle every 60 years.
Specific combinations: Jia Zi, Yi Chou, Bing Yin, ..., Jia Xu, Yi Hai, Bing Zi, ...
That is, heavenly stems and earthly branches took one stem or branch in their respective order to form a combination, with 60 species.
The ancients defined odd-numbered days as yang and even-numbered days as yin.
For example, this year is the year of Xu Bing and the year of Yang, because the sky is dry, Yin and Yang are fixed, and C is an odd number.
Similarly, the ancients also used these 60 combinations to calculate the month, day and time.
For example, it's morning, an ugly day, and an inappropriate day.
So a cloudy year, the moon is cloudy and the sun is cloudy, you can have many combinations.
For example:
Last August 1 day, the last day of the fifteenth day of the first lunar month was between the afternoon of the first lunar month 1 day and 3 o'clock.
However, in the four pillars, that is, the eight characters, it is determined that the heavenly stem is Ding and it is Ding Wei.
B, D and D are all dry on cloudy days, so the moon is cloudy and the day is cloudy.
There are hundreds of thousands of combinations of this cloudy day with cloudy moon and cloudy sun.