How many years will it take to catch up with the double spring year and the spring-free year?

How many years does double spring occur: 12 years.

Double spring year means that there are two solar terms in a year in beginning of spring, and double spring year generally occurs in leap month year. According to the normal month, the lunar calendar has 24 solar terms in a year, and after the 24 solar terms are replaced, it will enter the next year's solar terms replacement. However, due to the leap month, next year's beginning of spring solar terms will appear on this year's tail. So there is a "double spring year".

"No spring year" refers to a year in which there is no beginning of spring in the whole year of the lunar calendar. In order to adapt to the changes of cold and summer, the ancients added seven leap months every 19 years in the lunar calendar, resulting in no beginning of spring for seven years in 19 years.