Guides · Compass · 15 min read · Updated September 2026

Finding your facing direction

The compass methods depend on one measurement, and most readings go wrong before any chart is drawn. How to decide which way a house faces, how to take the bearing and how to check it against the sun, what the phone in your hand does to the needle, the two norths and the angle between them, the three rings of the luopan and which one to read, and what to do when the answer falls on a line.

Oriented NW 306°

Metal

Fig. 01 A coloured wall with windows in the sun. The facing of a house is its open, active side, which is usually where the light and the road are.

Everything the Compass schools say about a house begins with one number: the bearing it faces. Eight Mansions sorts houses by it, Flying Stars builds its chart from it, and the bagua is laid over the plan by it. It is also the number most often got wrong, because a house does not always face where its door is, because a compass does not always point where it should, and because a reading a degree either side of a boundary can change the whole result. This guide does the measurement properly, and gives the two checks, the sun and the map, that catch a needle that lies.

Which side faces

Fig. 01 Which way does a house face? A: the front door opens toward the road and the facing is where the door is. B: the door is on the side of the house and the big windows and the road are elsewhere; the facing is the open, active elevation, not the door. C: a flat in a block; most teachers take the facing of the building, some the flat’s own door onto the corridor, and the two readings can differ by ninety degrees. The dashed arrow is the facing in each case. Where a house is genuinely ambiguous, as in C, the compass methods that depend on the facing, Eight Mansions and Flying Stars above all, are the methods to trust least, because a facing wrong by one sector moves every reading with it. The Form School’s reading of the same house does not change.

The facing, xiang, is the side of the house that is open to the world: the side with the road, the view, the largest windows, the most coming and going. The sitting, zuo, is its opposite, the back the house rests on. In most houses the front door is on the facing side and there is nothing to decide. In a house whose door is on the side, or at the back, or off a shared corridor, the facing is not the door but the open elevation, and the schools say so with unusual agreement.

Taking the bearing

Plan 02 Taking the facing: three readings on the facing line, away from the wall, averaged The house faces the road at the bottom of the plan, so the facing is taken there: stand outside, back to the door, a metre or two from the wall, and read the bearing three times along the facing line. The three red dots are the three readings; average them, and the red arrow is the facing they give, which names a mountain, here S2. The sitting is the opposite point on the compass, here N2. Cars, railings, phones and the steel in the wall all move the needle, which is why the readings are taken in the open.

Stand outside the house on the facing side, with your back to the facing wall and a metre or two away from it. Hold the compass level and read the bearing you are facing: the direction the house looks toward, away from itself. Take the reading three times at three points along the facing line and average them. If the three differ by more than a few degrees, something is pulling the needle, and the reading should be taken again further from the wall. Write the number down before doing anything with it.

A phone compass will do for a first reading if it has been calibrated, which on most phones means turning it through a figure of eight until the app stops asking, and if it is held flat, away from the body and away from any case with a magnet in it; a real compass, or a luopan, is better for the final one, and a sighting compass, the kind with a mirror and a line, is better than a baseplate. The phone’s compass is a magnetometer that also knows where it is, and some apps quietly correct it to true north; check the setting, because the tradition’s bearings are magnetic and the correction, in some places, is the width of a mountain.

Two norths

Fig. 03 Two norths. Stand a stick upright on level ground; at local solar noon, when the sun is highest and due south, its shadow is shortest and points to true north, the north of the map and the stars. A magnetic needle points to magnetic north, which is somewhere else, and the angle between the two is the declination. It is a degree or two in most of Europe, which a compass method can ignore; it is ten to fifteen degrees in much of North America and Australia, which is the width of a whole mountain on the luopan. The tradition’s bearings are magnetic bearings, taken with a needle; a house whose facing is read from a map or a satellite image is read in true bearings, and the two disagree by the declination of the place. The values in the table are approximate for the mid-2020s and drift by a fraction of a degree a year; a national geological survey publishes the current figure for any place. Solar noon is not twelve o’clock: it is the middle of the day between sunrise and sunset, which any weather service gives. South of the tropics the noon sun is in the north and the shadow points south; the check is the same, turned round.

The needle points to magnetic north, and the map, the satellite image and the sun point to true north, and the angle between them, the declination, depends on where you stand. In London it is about a degree, in Rome about four, in Hong Kong three; in New York it is about thirteen degrees west, in Los Angeles eleven east, in Sydney thirteen east. The Compass schools use the magnetic reading, and so does this site: the luopan is a magnetic instrument and its tables were made for the needle. A reader who takes the facing from a map or an aerial photograph, which is easy and tempting, has a true bearing and must add or subtract the declination to get the one the tables want, and a reader in Ohio who does not has moved the house a whole mountain.

From bearing to mountain

The compass ring is divided into twenty-four mountains of fifteen degrees, three to each of the eight directions, and the Compass methods work in mountains rather than degrees. South runs from 157.5° to 202.5°, and its three mountains are S1 Bing, from 157.5° to 172.5°, S2 Wu, from 172.5° to 187.5°, and S3 Ding, from 187.5° to 202.5°. A reading of 178° is S2. The luopan page draws the whole ring with its names and polarities, and the Bagua Explorer turns any bearing into its sector.

The void lines, drawn

Fig. 04 The void lines, drawn on the ring. The twenty-four mountains meet at twenty-four boundaries, and a facing that falls within about two degrees of one of them is a void line, kong wang, which the Compass schools read as a house they cannot chart with confidence. Eight of the boundaries are worse than the rest: the ones where a trigram changes, at twenty-two and a half degrees and every forty-five after it, drawn heavy, since a house on one of them belongs to neither of two Eight Mansions groups and neither of two Flying Star charts. The sixteen between mountains of one trigram, drawn light, are the small void lines, and the school’s charts differ across them less. The tinted bands are the two degrees either side that a careful reading treats as the line, and they add up to about a fifth of the ring: a house has roughly one chance in five of sitting on a boundary of some kind, which is why the schools have rules for it. The reading marked at ninety-seven degrees falls on the small void line between E2 and E3, and the site’s advice for it is the note’s: report it as a void line, read the house by its form, and, if a chart must be drawn, draw both and trust neither where they differ. The practitioners’ older remedy, rehanging the door a few degrees off the line, is a real one and the design note gives it. The two-degree band is a common working width, not a canonical figure; Skinner gives the void lines and the practice of reading both charts. The eight great void lines are the trigram boundaries; the ring’s first mountain opens at 337.5 degrees.

The note above gives the rule and the ring above gives the geometry, which is worth seeing once, because it shows how much of the compass the rule covers. The twenty-four mountains meet at twenty-four boundaries, and a careful reading treats about two degrees either side of each as the line; those bands add up to close to a fifth of the ring, so that a house chosen at random has roughly one chance in five of sitting on a boundary of some kind. Eight of the boundaries matter more than the rest, the ones where a trigram changes, at twenty-two and a half degrees and every forty-five degrees after it, because a house on one of them belongs to neither of two Eight Mansions groups and neither of two Flying Star charts, and the two readings of it disagree about everything; these are the great void lines, and Skinner’s compendium gives them as the case the schools most warn about. The sixteen boundaries between mountains of one trigram are the small void lines: the Eight Mansions reading does not change across them, and the Flying Star chart changes less, so a house on one is a house with two similar charts rather than two opposite ones. The reading marked on the ring, ninety-seven degrees, falls on the small line between E2 and E3, and it is a common result, since the site’s own three-reading method gives an average to a degree and a degree is what a boundary is. What to do with it is the note’s advice made practical: write the bearing down as a void line and not as one mountain; read the house by its form, which needs no number; and, if a chart must be drawn, draw both and act only on what they agree about. The practitioners’ older remedy is real and the design note below gives it: a door can be rehung a few degrees off the line, which moves the facing without moving the house.

What the number is for

The bearing does three jobs. It gives the house its trigram in the Eight Mansions method, which sorts houses into East and West groups by their sitting; it gives the facing mountain from which a Flying Star chart is built, together with the period of construction; and it orients the classical bagua on the plan, so that the south-east sector is the actual south-east. None of these jobs needs more precision than a careful reading gives, and none of them survives a wrong one. Nothing in the Form reading of the house, the wall behind the bed, the door in view, the light from the side, needs the number at all, which is the reason the site does the form first and the compass last.

Checklist

Decide the facing side first: the open, active elevation, not necessarily the door
Read outside, back to the facing wall, a metre or two away from it
Three readings along the facing line, averaged, with the phone calibrated and the keys out of the pocket
Away from cars, railings, phones and reinforced walls
Magnetic bearing, as the tradition uses it; add the declination if the bearing came from a map
Check a doubtful reading against the noon shadow
Note the mountain (S2), not just the direction (south)
A reading on a boundary is a void line: say so rather than rounding it