What it is
Xuan Kong Da Gua (玄空大卦, "Mysterious Void Great Hexagram") divides the compass into 64 segments of 5.625°, one per I Ching hexagram, in the order of the Fu Xi circle. A building’s facing bearing lies in one segment and its back in the segment directly opposite — and those two hexagrams, read against the 20-year San Yuan period, are the reading. It describes the building, not its occupants: no birth data enters it.
The house read as two hexagrams on the 64-hexagram ring.
How it works
Your home's facing bearing is placed on the 64-hexagram ring (外盤): the segment it falls in gives the facing hexagram, and the segment 180° away gives the sitting hexagram. The two are always one another's inverse — every one of the six lines flipped (錯卦) — and so they share one 卦運 (the period number read from how each hexagram's upper and lower trigrams differ) while their 卦氣 numbers sum to ten. The 卦運 is then read against the current 20-year period: 卦運 1–4 belong to the upper half of the 180-year cycle (上元), 6–9 to the lower half (下元), and a pair is timely when it falls in the half the period stands in. A bearing within one line (0.94°) of a boundary between two hexagrams is reported as such, because a small measuring error would change the pair.
Key components
- 64-Hexagram Ring — The outer ring of the San Yuan compass: the 64 hexagrams in the Fu Xi circle order, 5.625° each. 復 opens at due north and 乾 closes at due south; 姤 opens at due south and 坤 closes at due north.
- Sitting/Facing Pair — The facing hexagram is the ring segment the front of the building looks into; the sitting hexagram is the segment behind it. Opposite segments are always a hexagram and its inverse (錯卦).
- 卦運 (Hexagram Period Number) — A number from 1 to 9 (never 5), read from which lines of the upper trigram differ from the matching lines of the lower. Sitting and facing always share it.
- 卦氣 (Hexagram Element Number) — The Early Heaven number of the upper trigram (乾 9, 兌 4, 離 3, 震 8, 巽 2, 坎 7, 艮 6, 坤 1). Its He Tu element: 1·6 Water, 2·7 Fire, 3·8 Wood, 4·9 Metal. The sitting and facing numbers always sum to ten.
- Period and Timeliness — The San Yuan calendar runs nine 20-year periods from the Li Chun of 1864; Period 9 runs from the Li Chun of 2024 to that of 2044. For a hexagram pair only the half matters: periods 1–4 are 上元, 6–9 下元.
- Boundary Lines (空亡) — A facing that lies on a line between two trigram palaces is called 大空亡, and one between two mountains of a palace 小空亡. A facing on a line between two hexagrams straddles two pairs; a finer compass reading decides which.
Your reading
Once you have a KAXANTA account, this section fills with your actual Xuan Kong Da Gua values — computed once from your birth data and refreshed as transits shift. Until then, this is the shape of what you'll see.
Every number in your reading traces back to a classical calculation — no AI fabrication, no synthetic guesswork. If something looks wrong, it's almost always birth-data accuracy.
How KAXANTA reads this
KAXANTA places your home's facing bearing on the 64-hexagram ring and names the facing hexagram, the sitting hexagram opposite it, their shared 卦運 and their two 卦氣, and whether the pair is timely in the current 20-year period (Period 9, 2024–2044). A bearing within one line of a hexagram boundary, or of a 大空亡 / 小空亡 line, is flagged. Requires your house facing in Settings. The ring and the period were adopted on 2026-09-28 (ADR-0010); readings made before then are recalculated.
I don't read Xuan Kong Da Gua in isolation — I weigh it against the other eight systems based on the question you're asking. Decisions, timing, psychology, and environment each have their own primary authority; Xuan Kong Da Gua contributes to the ones where its lineage is strongest.
Common questions
History & lineage
A San Yuan (三元) Feng Shui method that reads compass directions with the I Ching’s 64 hexagrams, laid around the compass in the Fu Xi (先天) circle.
KAXANTA presents Xuan Kong Da Gua faithfully, as its lineage presents itself. We don't sacralise it, we don't reduce it. If it consistently describes you better than generic advice would, use it. If not, lean on the other eight.
References & further reading
Canonical sources that informed this page. Wikipedia entries are starting points for cross-disciplinary context; books are practitioner-grade depth.