What is a broken sun! It is said that the New Year's Day is a broken day! Can't pay New Year's greetings! Why?

A sentence from the past almanac. Broken, broken, incomplete, bad. Breaking the sun is a bad day. Therefore, the first day is usually a family reunion, not going out, only paying New Year greetings among neighbors. The next day is also a dangerous day, and it is only within the village. I didn't go out until the third day. The third day is also called Chengri.