leap year rule in chinese calendar

In order to make any day in a month contain the meaning of the moon phase, that is, the first day is a moonless night, and about 15 are full moon, to the main month, while taking into account the season, the method of nineteen years seven intercalations is adopted: in the nineteen years of the lunar calendar, there are twelve ordinary years, each ordinary year twelve months; There are seven leap years, and each leap year is thirteen months.