The Water Formula — 龍門八局, the Dragon Gate Eight Formations — reads the water around a building: where it should arrive, and where it should leave. The sources that print its tables file it as a San Yuan (三元) water method. It has one input, the palace the building sits in, and from that palace it names eight positions, each with a reading for water arriving from that direction and water leaving toward it. The occupant’s Kua number does not enter it.
One input: the sitting palace
The compass is divided into the eight Later Heaven palaces, 45° each: 坎 north, 艮 northeast, 震 east, 巽 southeast, 離 south, 坤 southwest, 兌 west, 乾 northwest. The palace behind the building — its sitting, the facing turned 180° — sets the whole formation. Two people living in the same house share one formation; the same person moving to a house that sits another way gets a different one.
Arriving water and leaving water
Each position reads the two directions of flow separately. At the 先天 (Early Heaven) and 後天 (Later Heaven) positions, water arriving is read as supporting the household’s people and its wealth, and water leaving as their loss. At the 賓 (Guest) and 客 (Visitor) positions, arriving water favours those outside the household’s line — daughters, in-laws, tenants — and leaving water is harmless. 天劫 (Heaven Robbery) and 案劫 (Front Robbery, the facing palace itself) are where water should leave; water arriving from 天劫 is the formula’s worst case. Water must not leave through 地刑 (Earth Punishment). The palace left over is 輔卦, read like 先天 and 後天.
Why the direction of flow matters more than the water
The same stream can be the best thing on a site or the worst, depending on which way it runs. Water flowing toward the house from its 先天 palace and away through its 天劫 palace is the configuration the formula looks for; the same channel running the other way — in from 天劫, out through 先天 — is the configuration it warns against most. That is why a reading starts with the sitting palace and then asks, for each channel, drain and slope, where the water comes from and where it goes.
References
Canonical sources that inform this guide.
- 论龙门八局系水法 (华夏大易学社) · WEBSITE
- 三元水法龙门八大局 (简书) · WEBSITE
- Bagua (Eight Trigrams) · WIKIPEDIA
- Feng shui · WIKIPEDIA