Understanding the Principles of Xuan Kong Da Gua Feng Shui Li Qi in Ten Minutes

First published on the WeChat public account "Daoist Yinfu Culture," 2019-07-11. Illustrations omitted.

Xuan Kong Da Gua in feng shui li qi is modernly regarded as having little value, because its fenjin degrees are precise down to every line position — usually considered infeasible with ancient surveying.

Yet infeasible does not mean impossible. Fenjin precise to one degree was in fact possible in ancient times. At least as early as the Han dynasty, measurement and construction technology far exceeding this level could be achieved. A typical example is the corridor of the Guishan Han Tomb: it is perfectly straight, with a north–south alignment error of only one part in ten thousand.

Of course, royal tombs were far more difficult to construct. Whether such precise construction could be achieved on ordinary dwellings is indeed a question.

Setting those issues aside, let us discuss the principles of Xuan Kong Da Gua.

Xuan Kong Da Gua arranges the sixty-four hexagrams on the luopan (geomantic compass) according to the celestial circuit, and compares the upper and lower trigrams of each hexagram, determining the fortune period by line changes. The usual mnemonic verse is:

Tanlang unchanged, Period One arrives;
Period Nine, all changed — Bi should respond.

Period Two, Jumen — upper and middle change;
Period Eight, Fuxing — cut at the first line.

Period Three, Lucun — upper and lower change;
Period Seven, Pojun — middle embryo transformed.

Period Four, Wenqu — middle and lower;
Period Six, Wuqu — raise the top line.

This is the Xuan Kong hexagram-period verse; when combined with Zero and Correct, it brings descendants and wealth.

Although this verse is somewhat crude, what is its underlying principle?

If the nine periods are mapped to hexagrams, treating changed lines as yang and static lines as yin:

Period One corresponds to the Kun hexagram — Tanlang
Period Two corresponds to the Xun hexagram — Jumen
Period Three corresponds to the Li hexagram — Lucun
Period Four corresponds to the Dui hexagram — Wenqu
Period Six corresponds to the Gen hexagram — Wuqu
Period Seven corresponds to the Kan hexagram — Pojun
Period Eight corresponds to the Zhen hexagram — Fuxing
Period Nine corresponds to the Qian hexagram — Bi

It is actually arranged like this:

So once seen this way, the method of determining periods is clear. In essence, it is evolving the periods along the Nine Palaces trajectory on the positions of the Earlier-Heaven Eight Trigrams.

To know what hexagram period applies to a given hexagram, simply compare the upper and lower trigrams: record differences as yang lines and sameness as unchanged yin lines. Then place the resulting trigram into the Nine Palaces according to the Earlier-Heaven Eight Trigrams, and look at the corresponding Nine Palaces number to obtain the hexagram period. And Tanlang through Bi — the nine palaces — have in practice become synonyms for the Nine Palaces themselves.

Then, drilling down to each of the sixty-four hexagrams: the order of line positions on the luopan differs — some are counted in reverse, some in forward order. How is this determined?

Qian, Kun, Kan, and Li — occupying the four cardinal positions — are regarded as yang, while the four corners Dui, Xun, Zhen, and Gen are regarded as yin. If the yin/yang of the upper and lower trigrams differ, arrange in forward order; if the yin/yang are the same, arrange in reverse.

For example, in the Heaven-Earth Stagnation (Pi) hexagram, Qian is yang and Kun is yang; since they are the same, the arrangement is reverse — so arrange lines one through six counter-clockwise.

For another example, in the Heaven-Thunder Innocence (Wuwang) hexagram, Qian is yang and Zhen is yin; yin and yang combine — so arrange lines one through six clockwise.

Then in Xuan Kong Da Gua, as mentioned earlier, the Earlier-Heaven Eight Trigrams are distributed into the Nine Palaces; the resulting Nine Palaces number is called the star period. There is also a concept called hexagram qi — what on earth is this hexagram qi?

In ordinary materials, the so-called hexagram qi is explained in very convoluted terms — something like: the hexagram-qi five phases emerge from the Rat sitting-mountain, and to the left and right are nine, four, three, eight, two, seven, six, one; Kun and Gen's one and six belong to Water, Kan and Xun's three and eight belong to Wood, Gen and Zhen's two and seven belong to Fire, Qian and Dui's one and six belong to Metal. Following that reasoning easily overcomplicates the problem.

In fact, it need not be that complicated at all, because the distribution of the sixty-four hexagrams around the celestial circuit is regular — one can simply look at the diagram:

Arranging the Hetu numbers in Earlier-Heaven Eight Trigram order, yang trigrams are distributed 1, 3, 7, 9 and yin trigrams are distributed 2, 4, 6, 8.

Qian and Dui: Qian is yang so it is 1; Dui is yin so it is 6.

Li and Zhen: Li is yang so it is 7; Zhen is yin so it is 2.

The rest follow the same pattern.

For example, Heaven-Thunder Innocence (Wuwang): the upper trigram is Qian, so the hexagram qi is one. Earth-Thunder Return (Fu): the upper trigram is Kun, so the hexagram qi is nine.

So as long as you memorize this diagram, the whole of Xuan Kong Da Gua is essentially memorized.

Of course, the above is already marked out on ordinary Three-Yuan compasses — there is no need to worry about how to arrange it.

But once the principles are understood, the operating methods of Xuan Kong Da Gua become clear as well.

Those familiar with feng shui know the Dragon Gate Eight Formations or the Zhongtian water method. If water flow breaks the Earlier Heaven or Later Heaven, it is inauspicious. The so-called flow-breaking refers to when, with the Earlier-Heaven Eight Trigrams placed on the Nine Palaces diagram, either the hexagram or the palace is taken as the sitting mountain, and water exits from that hexagram or palace, causing the qi field to drain — this is "leaving the position."

If the incoming dragon is a palace or hexagram, and the lair is also a palace or hexagram, then it does not leave the position, and is judged auspicious — for example, Earlier-Heaven incoming dragon with Later-Heaven facing, or Later-Heaven incoming dragon with Earlier-Heaven facing, are all like this.

Because the incoming dragon and the facing are primarily static, they must be where the Correct Spirit resides; water is primarily moving and must be where the Zero Spirit resides. Water either combines with the hexagram-palace to make five, ten, or fifteen, or forms a generating relationship with the hexagram-palace, or is in the same hexagram or same palace — this is a configuration that matches, forming a formation capable of joint effort.

So although the Xuan Kong Da Gua looks very complex with sixty-four densely packed entries on the luopan, once spread out on the compass, it is actually not complex.

Although the theory looks quite good, is it truly practical?