What does the year of black spring mean?

The term "Black Year" is a folk rumor. Because on February 4th every year in beginning of spring, in order to adapt to the changes of cold and heat, the ancients added seven leap years every 19 years in the lunar calendar, that is, seven years without beginning of spring, seven years with double beginning of spring and five years with single spring. It means that there is no solar term "beginning of spring" at the beginning and end of the Lunar New Year. To put it more appropriately, "Black Year" is not so much a dialect vocabulary as an idiom of ordinary people. Everyone is familiar with the "beginning of spring" in the 24 solar terms. If there is no "beginning of spring" in a certain lunar year, it is called a "black year". Records of Sacrifice in the History of the Later Han Dynasty recorded the ceremony of welcoming the Spring in counties and cities: "On the day of beginning of spring, ten thousand people were graceful and green, welcoming the Spring outside Dongguo". It means to let a boy wear a green scarf and Tsing Yi, first in Dongguo outfield. Spring is the season when everything revives. If there is no spring in a year, the ancients thought that there would be no so-called "Yang". This year was named "Widowed Year", and later it gradually evolved among the people, becoming the so-called "Black Year" and "Widowed Year". Various rumors that black years are not suitable for marriage have also begun.