1. yang Wood
2. yin Wood
3. yang Fire
4. yin Fire
5. yang Earth
6. yin Earth
7. yang Metal
8. yin Metal
9. yang Water
10. yin Water

Note that these ten figures are used here merely to identify the ten Chinese characters known as the Ten Stems. They must not be confused with mathematical numbers, which according to the Lo Shu have a different significance. But it is worth remembering that both Stem 5 and Lo Shu number 5 represent the element Earth.

The Chinese Compass Plate

The Chinese compass plate, as found on a traditional Chinese mariner’s compass, does not divide the points of the compass successively by two, as does the familiar Western compass. Once the four principal points have been sub-divided into the Eight Directions (North, Northeast, etc), these eight directions further divide, uniquely, into twenty-four divisions. The curious system is based on the need of the astronomer to correlate the twelve divisions of the sky (marking the twelve months of the year, and the twelve years of the Great Cycle of twelve years) with the twelve divisions of the clockface.

Innermost ring : Eight trigrams, or directions

Middle ring : The twelve branches, or months

Outermost ring : The ten stems, omitting 5 and 6

The twenty-four Chinese compass points

Unfortunately, the clockface is not divisible into eight, so in order to distribute the Eight Directions equally with the twelve divisions, the compass face is divided into twenty-four.Four of the Eight Directions, the cardinal points, match the clockface positions, so the other four ‘corner’ directions, North-east, North-west, South-west, and South-east, are assigned to their appropriate places. This leaves eight positions so far unnamed. These are the positions on either side of the cardinal points. Noting which stems are associated with the elements, we see that Stems 9 and 10 belong to Water, which is the element of the North. These two stems were therefore placed in the vacant positions on either side of the North position, occupied by Branch I.
The reader who follows this reasoning will then see why 1 and 2 are placed on either side of the east position at Branch IV, and Stems 3 and 4 on either side of VII in the South, symbolizing Fire. In the West, symbolizing Metal, Stems 7 and 8 are placed at each side of Branch X . This leaves Stems 5 and 6 unaccounted for, which is appropriate since these stems are associated with the element Earth, representing the Centre.The evolution of the Chinese compass plate is shown in the diagram above. The system may appear complex, but it is extremely ancient. An actual example of a diviner’s board, showing the stems and branches in these positions, has been excavated from a tomb dating from the first or second century BC.

Repetition of the Compass Points

On most examples of Lo P’an the twenty-four compass points are repeated twice, one ring 7½º clockwise, and the other 7½º anticlockwise of the principal orientation of the compass points. Various theories have been put forward to account for this repetition, including the possibility that the shifts represent an awareness of variations in the earth’s magnetic field. The real reason derives from actual Feng Shui practice.We shall see shortly that each of the twenty-four compass divisions is related to a particular Feng Shui ‘star’ as well as to other factors, such as the twenty-four solar fortnights. But also, the eight divisions of the compass relate to the eight orientations of a site. Suppose that the orientation is Chinese compass direction Stem 10, to the West of true North. From the point of view of the Eight Trigrams, this orientation is the same as that for true North ; but the equivalent divisions of the twenty-four point compass dial are out of alignment for stem 10; accordingly the geomancer consults that version of the compass ring which is shifted 7½º clockwise, in which true North is aligned with Stem 10.The three arrangements of the compass dial are known by distinguishing names. The one aligned with true North is called the ‘true needle’; the next ring, displaced 7½º anticlockwise, is the ‘middle’ needle (presumably on account of its having been placed between the true needle and the next); and the one displaced 7½º clockwise is the ‘seam’ needle.

Equating Compass Points with the Calendar

Since there are twenty-four compass points, each of these may be equated with one of the solar fortnights listed on the calendar, as well as with one of the hours of the Western day. The Chinese divide their twelve hours into twenty-four ‘fore’ and ‘aft’ ‘little-hours’. Midnight marks the mid-point of Branch I (the Rat) double-hour, which last from 11 p.m. to 1 a.m. The first ‘little-hour’ of the day is therefore 11 p.m. till midnight ; the second ‘little-hour’, midnight till 1 a.m.

The Twenty-Eight Lunar Mansions

The twenty-four solar fortnights enable the Lo P’an operator to find the earth’s celestial position by compensating for its daily rotation with its annual orbiting of the sun. But it is not a very accurate system. Usually, on the edge of the Lo P’an, there is a ring of 365¼ divisions, one for each Chinese degree. Each degree therefore represents one day’s change in the sun’s position. By this means, the Lo P’an can also be used both as a terrestrial compass and a planisphere. For the latter purpose, next to the degree circle are marked the positions of the twenty-eight Chinese constellations that lie along the celestial equator. By noting the position of the full moon, which always occurs on the fifteenth day of the Chinese month, the operator is able to determine the sun’s position among the stars, the full moon always occupying the part of the sky directly opposite to the sun. These factors enabled the olden-day Feng Shui professor to calculate the times and dates of eclipses, and the course of the solar year. The names of the twenty-eight to make direct correlation between the dates of the Western year constellations are listed below; they are considered to have a greater or lesser benign influence. It is possible to make direct correlation between the dates of the Western year and the degrees of the twenty-eight lunar mansions. The positions of the constellations, however, move by one degree, or day, every thirty years or so; Lo P’an of different periods alter positions of the twenty-eight mansions to account for this gradual change. To digress beyond these introductory remarks on the use of the Lo P’an as an astronomical instrument would, however, be beyond the scope of this book.