What do you mean by "four bright days in the yellow calendar"?

There are twelve eclipses and the underworld.

However, in Cantonese, because the word "Shu" in general books is homophone with the word "lose", it is also called "Tong Sheng" because of taboo. The main contents of the Gregorian calendar are 24 solar terms, such as daily taboos, dry branches, spiritual values, stars, moon phases, zodiac luck, auspicious and evil spirits (ecliptic, underworld) and so on.

"ecliptic" is a special term in astronomy, which has ecliptic and equator, but no "underworld"; The concept of "evil day in the underworld" is a term created by the ancient yellow calendar compilers, which is related to "auspicious day in the zodiac".

Traditional calendar:

The yellow calendar is a combination of the Gregorian calendar, the lunar calendar and the official calendar. It is called the yellow calendar, also known as the old yellow calendar, the yellow calendar, and the children's life. It is an almanac, which contains a lot of rules and contents related to seeking good fortune and avoiding evil. Almanac is a code of conduct followed by ancient emperors and a calendar promulgated by emperors, so people call it "imperial calendar"; After the Revolution of 1911, the imperial system was overthrown, and the "imperial calendar" was renamed as "yellow calendar" by homonym.

The yellow calendar not only includes astronomy, meteorology, seasonal seasons, but also contains some taboos that people should abide by in their daily lives. Its contents guide the farming opportunities of working farmers in China, so it is also called farmers' calendar. The people of the Yellow Calendar are also commonly known as "general books".