The Yi people are an ancient people with a long history in the family of the Chinese nation. In the long river of human civilization development for thousands of years, the Yi people have created a dazzling national culture. The Yi October solar calendar is a great and exquisite astronomical calendar created by the Yi ancestors. It divides a year into five seasons and ten months, two months every quarter, 36 days per month, a total of 360 days, and the remaining 5-6 days are the New Year's Day. It accurately calculates that the time of the Earth orbiting the sun for a week is365.25 days, and the season of the year is accurate to one day.