Why Your Feng Shui Kua Number Formula Depends on Gender
The Feng Shui Kua number isn't a scientifically validated system, but the arithmetic behind it is real and checkable — and unlike most numerology methods, it needs your gender as an input, not just a birth date.
How the Kua number is calculated
Take the last two digits of your birth year, sum them, and reduce that sum to a single digit. From there, men and women run different formulas on that digit — traditionally 10 minus it for men born before 2000, 5 plus it for women, with slightly different constants for people born in 2000 or later. Same birth year, same reduced digit, different final number depending on gender — that's not an error in the system, it's built into the classical Eight Mansions (Ba Zhai) method itself.
Why "Kua 5" doesn't exist
The formula can land on 5, but tradition doesn't treat 5 as a real Kua number — it gets remapped, to 2 for men and 8 for women. That's why you'll never find a "Kua 5" direction table or reading anywhere: every Feng Shui reference silently substitutes 2 or 8 the moment the arithmetic produces 5.
Check your own
Synastri's `/feng-shui-kua` calculator runs this exact year-digit-sum and gender-based formula on your real birth year — including the 5-to-2/8 remap and the pre/post-2000 split — then maps your number to its four auspicious and four inauspicious compass directions from the standard Eight Mansions tables. For entertainment, not a scientifically validated system.