Why Did the Ancients Highly Value Picking Auspicious Days?

As someone who has studied Chinese Astrology for many years, I am often asked, "Is choosing auspicious days effective, or is it just superstition?"

Let me start by sharing a real experience.

In 2019, a friend planned to open a restaurant on a weekend (targeting high foot traffic). After analyzing his BaZi, I found that day conflicted with his Destiny Pattern, and the Five Elements for that date clashed severely with his BaZi. I suggested he delay and choose a day more harmonious with his BaZi.