Chapter 62 Section 4 Yi Calendar

The current Yi calendar has 12 months in an ordinary year and 13 months in a leap year. Experts and scholars have conducted many field investigations and found that the pure solar calendar with 10 Gregorian months was widely used in the Yi area, and obtained several monographs written in Yi language, among them the Mile County in southern Yunnan. His "History of Astronomy and Calendar" was transcribed in 1895, which records the history of the establishment of the October calendar by the leaders of the Yi nationality in ancient times.Studies have shown that the October calendar of the Yi people is very ancient, and it has been confirmed that it has the same origin as "Xia Xiaozheng".The Yi people have been using the October calendar since ancient times, and they did not switch to the lunar calendar until the Ming and Qing Dynasties, but some remote areas were still using this calendar until 1949.

The ancient Yi calendar has 10 months in a year, 36 days in each month, 360 days in total.There are three zodiac weeks in each month and 36 zodiac weeks in each year.The remaining five or six days are used as New Year's Day alone.There are two New Years in one year in the ancient Yi calendar. The big year is called the Xinghui Festival, roughly in December of the Han calendar; the small year is called the Torch Festival, roughly in June of the Chinese calendar, and the difference between the big year and the small year is fixed by 185 days. , for half a year.There is no distinction between big and small months.Uniformity is an important feature of the ancient Yi calendar.

In the ancient books of the Yi people, the azimuths of the sun, moon and planets and the law of solar and lunar eclipses are also recorded.The Yi nationality basically divides the starry sky according to the twenty-eight constellation system, and there are 148 named stars.In the Naxi area of ​​the Yi language branch, there is also a unique system of twenty-eight mansions and twenty-seven mansions in rotation to record the days, that is, 28 days are the big moon and 27 days are the small moon, and the cycle alternates.The Yi area is slightly different, with two cycles of 27 days followed by one of 28 days, with an average month length of 27.33 days. From an astronomical point of view, this month is equivalent to a sidereal month.Although the sidereal month calendar system has never been heard of in other ethnic groups, it has a great influence on the Yi and Naxi ethnic groups.This kind of calendar system is generally only used for religious sacrifices or divination.As for the origin and spread of the sidereal calendar day, it remains to be further studied.