How much does birthday have to do with Zhouyi?

I think the Book of Changes is sixty-four hexagrams. My understanding of the so-called sixty-four hexagrams is what people should do in sixty-four situations and what kind of methodology they need. For example, what to do as a leader and what to do as a deputy.

As for the study of birth and numerology, I personally think that heavenly stems and earthly branches used statistics in ancient times, and heavenly stems and earthly branches was used in Zhouyi's counting. He used heavenly stems and earthly branches as a number to judge good or bad luck. It is estimated that the relationship with Zhouyi is so deep, or deeper, I don't know.

If the landlord really wants to know, just buy the original Book of Changes. Where there is a birth, except heavenly stems and earthly branches, everything else has nothing to do with the eight-character numerology.