A few volts of content

In the lunar calendar used in China, there is a branch calendar, which uses 10 for "heavenly stems" (A, B, C, D, E, G, Xin, Ren and Gui) and "earthly branches" (Zi, Ugly, Yin, Mao, Chen, Si and Wu). According to the provisions of the Chronology of Branches and Branches, the third Geng day from summer to the future is the starting date of the first lodging, the fourth Geng day is the starting date of the intermediate lodging, and the first Geng day after beginning of autumn is the starting date of the final lodging. It is stipulated that the first lodging and the final lodging are 10 days respectively. According to this rule, the summer in some years is 10 days, and the summer in some years is 20 days.

Modern calendars are rarely marked with "dry-branch" calendars, and it is generally impossible to see which day is "Geng Day", so it is necessary to look up the "Yellow Calendar". The summer solstice of 20 10 is June 2 1 (the main branch is Renyin), and the first Geng day after that is June 29 (the main branch is Geng Xu). Then, the third Geng Day is July 19 (Gengwu), which is the first day of the first autumn, and the fourth Geng Day is July 29th.

If that day in beginning of autumn happens to be Geng Day, it should start from the next Geng Day, not from the day in beginning of autumn. Take 20 12 as an example. August 7th, 20 12, beginning of autumn, the main branch of that day was "Geng Zi", and the last day was the next "Geng Day" on August 7th/kloc-0. Because every year in beginning of autumn, whether it is August 7th, 8th or 9th, if that day happens to be Geng Day, then this Geng Day will start at 23: 00 the day before, that is to say, it will arrive before beginning of autumn, so the first Geng Day after beginning of autumn is ten days later.