The auspicious day of the zodiac is a unique word in the traditional Chinese calendar "Huang Calendar" (perpetual calendar), which refers to a day when everything is suitable. It is suitable for days such as marriage, marriage, engagement, dating, opening, market opening and moving. The Yellow Calendar refers to the "Qinglong, Tiande, Yutang, Siming, Mingtang, and Jinkui" in the "Twelve Gods and Demons" as the "Six Zodiac Days", and the "Except, Danger, Dying, Persistent, Successful, and Open" in the "Twelve Duty Days" as the "Small Zodiac Days". In the old "Imperial Calendar", in addition to the days of Ganzhi Keji, another 12 characters were added to the date and made into a formula. That is: the year of completion is very dark (underworld), except for the danger of persecution and yellow (ecliptic), it can be used when it is completed and opened (ecliptic), and it cannot be closed and broken (underworld). In this way, every day is artificially divided into "auspicious days of the zodiac" and "fierce days of the

The so-called yellow underworld is a natural phenomenon in celestial bodies. Predecessors have summarized the laws of this phenomenon's impact on human beings, and have formulated the yellow underworld day around the twenty-eighth star. This provides a certain reference and choice for human survival and development, seeking good luck and avoiding evil.