Most feng shui principles apply to buildings — the command position, the elemental balance, the flying star chart. The Kua number system (part of the Eight Mansions school, 八宅 Ba Zhai) is different: it applies to people. Calculated from birth year and gender, each person has a Kua number that determines four auspicious directions and four inauspicious ones — and knowing which way you naturally face when sleeping, working and sitting reveals whether your environment is supporting or resisting you at the most fundamental energetic level.
The Kua number calculation differs for males and females and uses the Chinese solar year (beginning February 4th or 5th, not January 1st — if you were born in January or early February, use the previous year for the calculation).
The nine Kua numbers divide into two groups — East and West — and this division is the most practically useful thing to know about the system. An East group person is energetically aligned with east-facing directions; a West group person is aligned with west-facing directions. When a person's sleeping or working direction is in their own group, the environment supports them. When it is in the opposing group, there is energetic friction.
Each Kua number has four auspicious and four inauspicious directions, each with a specific quality. The four auspicious directions are ranked in order of power:
Kua number quick reference — Sheng Qi (best) direction: Kua 1 → Southeast | Kua 2 → Northeast | Kua 3 → South | Kua 4 → North | Kua 6 → West | Kua 7 → Northwest | Kua 8 → Southwest | Kua 9 → East. To use this: calculate your Kua number, find your Sheng Qi direction, and orient your primary work desk to face that direction. This single adjustment — which requires only a compass and a willingness to rearrange your desk — is considered by Ba Zhai practitioners to be one of the highest-impact personal feng shui adjustments available.
The four inauspicious directions are also ranked, from mildly challenging to most challenging. Knowing these helps you understand which current arrangements might be creating energetic friction:
禍害 Huo Hai (Mishaps) — minor accidents, petty irritations, wasted effort. The least challenging inauspicious direction — not a crisis, but a persistent background friction. 六煞 Liu Sha (Six Killings) — relationship problems, romantic difficulties, feelings of being undermined by those around you. A bed facing this direction is associated with relationship strain. 五鬼 Wu Gui (Five Ghosts) — financial loss, theft, fire risk, instability. More challenging — the Five Ghosts direction is particularly inauspicious for the stove and the main entrance. 絕命 Jue Ming (Total Loss, Worst) — the most challenging inauspicious direction, associated with serious health issues, major setbacks and the depletion of vitality. The most important direction to avoid for the bed, the desk and the main entrance orientation.
The Ba Zhai system, applied fully, would orient every piece of furniture and every activity in your home toward your personal auspicious directions. In practice, this is often impossible — and the system itself provides guidance on priorities: focus on the three positions where you spend the most time (bed, desk, stove) and the two most powerful directions (Sheng Qi and Tian Yi). The other positions and directions matter less.
Step 1: calculate your Kua number (use the formula above). Step 2: identify your Sheng Qi and Tian Yi directions. Step 3: take a compass reading of where your desk faces and where your head points when you sleep. Step 4: if either is in your four inauspicious directions — particularly if your desk faces your Jue Ming direction or your bed faces Liu Sha — consider rearranging. Step 5: if rearranging is impossible, note the direction mismatch and compensate through other feng shui means (stronger elemental support in those areas, clearer command position, better space clearing).
The Kua system is the most widely used feng shui personalization tool — and the one most widely misapplied. The most common error is treating Kua as a standalone system: "I am Kua 4, so I should face North" — and facing North regardless of the command position, the form school situation, or the flying star chart. The Kua number provides personal direction guidance; it operates within the building's overall feng shui situation. A bed facing your Tian Yi direction but with the head in line with the door and a mirror reflecting the sleeper is still a poorly placed bed.
The gender distinction in the calculation is traditional and not universally applied. Classical Ba Zhai uses the binary male/female distinction in its formula. Contemporary practitioners working with non-binary or trans clients handle this differently — some use biological sex assigned at birth, some use the gender the person identifies with, some offer the client both numbers and let them determine which resonates. The system's traditional framework does not address this; the honest position is that this is a point where contemporary practice necessarily departs from classical text.
The system works best as one layer among several. A person whose Kua direction aligns with the command position, who sleeps in a well-placed bed in a well-placed room in a home with a favorable flying star chart — all pointing the same way — is in an environment where multiple layers of the system are reinforcing each other. A person who has optimized their Kua direction alone, without attention to the other principles, has made a partial adjustment. The Kua number is most powerful as confirmation and as tie-breaker — when multiple bed positions are possible, choose the one that faces your Tian Yi direction. When one position is clearly required by the command position, use it, and note your Kua direction for secondary adjustments.