The House Sits on a Hexagram

Sitting and facing are one axis

Facing is the direction the building presents outward — conventionally the side carrying the main entrance, the most open aspect, or the street frontage. Sitting is the direction directly behind it, 180° opposite. A house that faces south sits north. Fix one and the other is determined, so the method reads the axis rather than either bearing alone.

The ring: sixty-four hexagrams around the compass

Xuan Kong Da Gua lays the 64 hexagrams around the compass in the order of the Fu Xi circle, one every 5.625°. Starting at due north and going clockwise, the thirty-two hexagrams whose bottom line is solid run through the east to 乾 (The Creative, ䷀), which ends exactly at due south; 姤 (Coming to Meet) opens the second half at due south, and the thirty-two whose bottom line is broken run on through the west to 坤 (The Receptive, ䷁), which ends exactly at due north, where 復 (Return) opened the ring.

Each 45° block of the ring shares one lower trigram, in the Early Heaven order — 震, 離, 兌 and 乾 through the eastern half, 巽, 坎, 艮 and 坤 through the western — and each block holds one hexagram of every period number. The facing hexagram is simply the segment the facing bearing lies in: divide the bearing by 5.625 and count from due north.

The pair: a figure and its inverse

The sitting hexagram is the segment directly behind the facing, thirty-two places round the ring. Because of the way the circle is built, that segment is always the facing hexagram’s inverse (錯卦) — every one of the six lines flipped, solid for broken and broken for solid. Two things follow for every house on earth:

• One 卦運. A hexagram’s period number, from 1 to 9 but never 5, is read from which lines of its upper trigram differ from the matching lines of its lower trigram. Flipping every line changes nothing about which lines differ, so facing and sitting always share it.
• 卦氣 that sum to ten. A hexagram’s element number is the Early Heaven number of its upper trigram (乾 9, 兌 4, 離 3, 震 8, 巽 2, 坎 7, 艮 6, 坤 1). Inverting a trigram swaps it for its complement, and complements always sum to ten: 9 and 1, 4 and 6, 3 and 7, 8 and 2.

The period: which half of the cycle

The San Yuan calendar counts nine 20-year periods from the Li Chun of 1864. For a hexagram pair only the half of the 180-year cycle matters: 卦運 1–4 belong to 上元, 6–9 to 下元. Period 9 — from the Li Chun of 2024 to that of 2044 — belongs to 下元, so in these twenty years a pair with 卦運 6, 7, 8 or 9 is timely and a pair with 卦運 1, 2, 3 or 4 is not. The halves swap at the Li Chun of 2044, when Period 1 opens.

Worked example: facing due south

Take the house that sits north and faces south — the most conventional orientation in Chinese building. Here is what the ring gives for facings around due south, computed by our engine for September 2026:

Due south is exactly where 乾 ends and 姤 begins. A facing of 180° lies on that line, so it belongs to two pairs: 乾 over 坤 on one side, with 卦運 1 and no standing in Period 9, and 姤 over 復 on the other, with 卦運 8 and timely. Across twenty degrees of what anyone would call "facing south", the verdict changes three times.

That is the whole practical lesson of the ring. The conventional south-facing house is not favoured or disfavoured as a class; each one is read from its own bearing, and the bearing has to be good.

Getting the bearing right

A hexagram covers 5.625°, and each of its six lines (爻) 0.9375°. A facing within one line of a boundary — 175° and 185° in the table above are both inside that margin — should be measured again before the reading is trusted, and one exactly on a boundary stays on it until a finer measurement decides. The San Yuan schools also name two compass lines to avoid: a facing between two trigram palaces is 大空亡, one between two mountains of a palace 小空亡.

So take the reading properly: outdoors, several metres from the structure, away from cars and metal, three or more times along the facing wall. Correct it for your local magnetic declination, which is often several degrees. We can tell you what your bearing implies, and we flag a bearing that sits too close to a line; we cannot tell you whether the bearing you saved is right.

What it is and is not

Xuan Kong Da Gua reads the building: the pair, their shared 卦運, and where the period stands. It does not read you — there is no Kua number here and no birth data — and it does not give each room its own hexagram. For which directions suit a person, the Eight Mansions method and its Kua number answer a different question, and the two sit side by side rather than in competition.

Correction, 28 September 2026: an earlier version of this article described a method that stacked the trigrams of the sitting and facing palaces into a pair, rated the pair on the element relation of the two palaces, and gave each of the eight sectors a hexagram. That is not how Xuan Kong Da Gua places hexagrams. The article, and KAXANTA’s reading, now use the classical 64-hexagram ring.