Origin number
Reduce the day of birth to one digit.
Master number
Sum all eight digits of the date once and reduce.
Kua
Sum the last two digits of the birth year and reduce to r. For births before 2000, men take 10 minus r and women r plus 5; from 2000, men take 9 minus r and women r plus 6. January births use the previous year. Kua 5 does not exist: men take 2 and women 8.
A worked example
This part is worked out by the calculators: open the calculator.
What each is for
The Origin and Master numbers read names, partners and dates. The Kua gives the desk-facing direction (Sheng Chi) and goes into the Lo Shu grid in the Indian convention.
Frequently asked questions
Why no Kua 5?
The Eight Mansions system has eight numbers; 5 is reassigned by sex.
Does the Kua use the solar year?
The classical rule uses 4 February; NumeroPandit uses the January rule practitioners state.
What are the East and West groups?
East 1, 3, 4, 9; West 2, 6, 7, 8.