Yan Dui
The day directly opposite the monthly Yin Sha (Yan), traditionally also avoided for marriage and long-distance travel.
Yan Dui is an inauspicious star closely related to the monthly Yin Sha (Yan), specifically referring to the day directly opposite (in opposition) to the monthly Yan. Since the monthly Yan itself is already highly inauspicious, the sha energy of its opposite day is also considered very unfavorable. Therefore, in the past, on Yan Dui days, people would similarly avoid holding marriage ceremonies and traveling far. This reflects the concept in traditional date selection that the influence of an inauspicious star also extends to related days (such as its opposite day), striving to avoid all possible risks for important matters.