How are twelve calendars and calendars completed?

In ancient 100 calendars, most of them are combined calendars of yin and yang, that is, the apparent movement period of the sun is in years, and the period of the moon is the position of the month. Because there is no integer multiple between them, it is inevitable to take some adjustment measures. However, in history, there are two calendars designed by pure solar calendar, which avoids this problem. One is the Twelve Calendars of Qi proposed by Shen Kuo, and the other is the calendar promulgated by the Taiping Heavenly Kingdom. Shen Kuo, a famous scientist, recorded his experiences and gains in studying various problems in life in the scenic Meng Xi Park in his later years, and wrote the famous Dream Stream. The book puts forward the first 1 solar calendar scheme in Chinese history: every year 12 months, the big month 3 1 day, the small month 30 days, and the big and small months alternate. Twenty-four solar terms are divided into two groups: beginning of spring, Jingzhe, Qingming, Changxia and Mangzhong, which are called solar terms and placed at the beginning of each month. Rain, vernal equinox, Grain Rain, Xiaoman, summer solstice ... are called Zhongqi and placed in the middle of the month. In this way, the date and solar terms of each year are fixed, and there is no need to set a leap month, so the calculation is very simple. Shen Kuo's solar calendar scheme is unprecedented. He knew that he would be attacked, but he still firmly believed that this design would always be used in the future.

As predicted by Shen Kuo, 800 years later, the Taiping Army promulgated the "Calendar".

The basic structure of Tian Li is 366 1 year, and there is no leap month. Single month 3 1, double month 30, solar term is the first month, gas is the middle of the month. Every month, the big moon starts on 17 and the small moon starts on 16. In this way, except for beginning of spring, Qingming, Mangzhong, beginning of autumn, cold dew and heavy snow, the six solar terms are 16 days, and the rest are 15 days, so it is very concise and neat, and almost everyone can use its calculation method to calculate the calendar spectrum. "Tian Li" kept the ancient method of recording years, days and months, and used the week-by-week method. It began in the beginning of spring. The calendar of beginning of spring 1852 is consistent with the calendar of the Qing Constitution, and beginning of spring is about the epoch of this year.

The tropic year of Tian Li is 366, which is probably for neatness, completeness and convenient calculation, but this value is quite different from the real value, which is 3 days different from 4 years. Considering this shortcoming, Hong Rengan, leader of Taiping Heavenly Kingdom, revised the calendar every 40 years in 1859. Specifically: every 40 years, it will be changed to 28 days per month; Each solar term is constant at 14 days. After this revision, the length of the tropical year of the calendar is equivalent to the international calendar of ancient julian calendar or China.