4 Pillars (四柱命理)

8 Characters or 10 Characters, Balanced or Harmony (8文字または10文字、バランスまたはハーモニー8)

In BaZi (八字), it is often related to the 5 Elements (五行) and getting it balanced. And so we have 8 characters in the BaZi (八字) to divide among 5 Elements (五行).

Therefore mathematically, 8 divide by 5 = 1.6
So, each element needs to be 1.6 of a character to be effectively balanced (but, how to cut up the character to have 0.6 of a character?).

Perhaps, in essence when the ancients created this system of astrology, it was never meant to be balanced but constantly in motion toward the state of harmony. And therefore in momentum, balance is achieved.

Or, we could use the natal chart + luck pillar to form exactly 10 words. Hence, mathematically achieving 2 words per element (as a form of balance).