House direction lookup

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What are the Kua number and Eight Mansions feng shui?

Bát Trạch Minh Cảnh (Eight Mansions feng shui) is a classical Chinese school that splits everyone into two destiny groups by birth year (East Four Life and West Four Life), each with 4 favorable house/desk-facing directions ("four auspicious": Vitality, Health, Longevity, Stability) and 4 unfavorable ones ("four inauspicious": Total Loss, Five Ghosts, Six Killings, Mishap), based on the Later Heaven Bagua (8 trigrams mapped to 8 directions) from the I Ching.

To find which group you belong to, you first need your Kua number (Cung Phi), a number from 1-9 (excluding 5) derived from your lunar birth year via a digit-reduction formula, adjusted with a fixed constant, with separate formulas for men and women (because the Later Heaven Bagua assigns the Khôn trigram to men and the Cấn trigram to women at the central position, rather than a direct numeric mapping). From the Kua number you look up your East/West Four Life group and its 8 corresponding directions.

This tool calculates your Kua number from the birth year you enter, then looks up your 4 favorable/4 unfavorable directions per the traditional Bát Trạch Minh Cảnh table. Note that this is birth-year-based feng shui (the "Eight Mansions" school), distinct from facing-and-construction-year-based feng shui ("Flying Star"/Xuân Không). The two schools can reach different conclusions about the same house, and in professional practice are usually weighed together with many other factors (terrain, interior layout, lighting) rather than used in isolation.

Within the East Four Life group, the 4 favorable directions in descending order of strength are Sinh Khí (Vitality, the strongest, tied to wealth and vigor), Thiên Y (Health, tied to well-being and stability), Diên Niên (Longevity, tied to relationships and harmony), and Phục Vị (Stability, the mildest, tied to personal growth and self-cultivation). The West Four Life group has its own equivalent 4-tier ranking among its favorable directions, following the same underlying logic but mapped to a different set of trigrams.

Because the Kua number depends on your LUNAR birth year, not the solar year, someone born in January or February (when the lunar year may not yet have turned over) can end up with a different Kua number than a naive solar-year calculation would suggest. This tool handles that conversion internally using the same lunisolar logic as the Lunar Calendar tool, so you only need to enter your ordinary solar birth date.

In practice, Bát Trạch is most often applied to a home's main door direction or a desk's facing direction, since these are the openings through which "life energy" (khí) is said to enter. It is less commonly applied to interior room placement, which more traditional practice reserves for other feng shui techniques (room function assignment, Flying Star period calculations) rather than the 8-direction Kua system alone.