How to calculate the solar projection in the lunar calendar

According to Du Niang's explanation, the social time of the Spring Festival is generally the fifth day after beginning of spring, which is pushed from the old almanac in the order of sixty jiazi, and every sixty days is a round. Among them, Wuzi, Wuyin, Chen Wu, Wuwu, Wushen and Wuxu are called Wuri, also known as "Liu Wu". Beginning of spring is February 4th. View old calendars. After beginning of spring, February 1 1 is Wuwu Day, February 2 1 is Chenwu Day, March 3 is Wuyin Day, March 13 is Wuzi Day, and March 23 is Wuxu Day.