This information is part of the series of articles answering the feng shui IQ quiz.

Feng shui uses the orbit of Jupiter to determine some cycles of time.

True.

Every 12 years Suixing [Jupiter] returns to the same position in the sky; every 370 days it disappears in the fire of the Sun in the evening to the west, 30 days later it reappears in the morning to the east.
— attributed to Gan De, in the Suixing jing (Treatise on Suixing)

The so-called Chinese zodiac is based on “Jupiter time.” The Earthly Branches derive from tracking the 12-year orbit of Suixing. Actually the orbit takes 11.86 Earth-years, but Chinese astronomers rounded it off to 12 (to harmonize with Earth-years), then matched the orbit with the xiu (“lunar mansions”) along the ecliptic (Yellow Road). Astronomers defined a “year” as the sector of sky that Suixing moved into at a particular time. This system is called the 12 ci (“12 Jupiter stations”).

Five sets of the 12 Branches complete the Jovian cycle of grand conjunctions with Saturn (5 x 12 = 60).

Time as an angle

A more precise version of the Branches consists of 24 points within the meteorological cycle. These are found on a Luopan as the 24 Mountains. They coincide with other points 15º apart on the ecliptic.

It takes about 15.2 days for the sun to traverse a point. The series of points on the ecliptic creates a cycle of 365.25 days, which means that each degree on a Luopan ticks off a day. (See page 48 in my book for the relationships between the jieqi and zhongqi, Gregorian dates, and solar longitude.)

Clocks in the sky and in your hands

From Earth, Suixing seems to have an erratic orbit, so it is useless as a timepiece. To remedy this problem, ancient astronomers created a mirror image of Suixing that moved clockwise, opposite of the direction of the 12 ci. This system is the 12 chen (12 Branch Division). Suixing could be used for timekeeping thanks to this invention.

According to recent evidence the Shang may have been using the ci and chen, because at least by 1350 BCE they used the ganzhi (Stem-Branch system) as a day-count. The space-time attributes associated with liuren astrolabes (ancestors of the Luopan) were transferred to the ganzhi, not the other way around. Almost a thousand years after the Shang, the ganzhi would start being used to keep track of years.

If the Shang were counting the 12 chen, they were using liuren astrolabes, because the 12 chen and the liuren astrolabe are inseparable. A liuren has always counted the 12 chen. Unfortunately, liuren have not yet been found from the time of the Shang or Zhou.

Researchers are certain that the 12 chen are older than the earliest mention of them. For example, in Chinese myth Fuxi is Suixing, born after twelve years as a fetus, becoming king at the age of 12 (at “birth,” the point where the cycle begins), and reigning 11 years.

San Yuan Xuan Kong and astronomy

Space and time are the heart of San Yuan (3 cycles) feng shui. However, the Internet abounds with people who believe calculations have no relation to the heavens, although it is apparent from literary and archeological evidence that this assertion is not correct.

Suiyin, Taisui, Taisuixing, and Taiyin (Daiyin or “Great Yin”) are all terms for the Great Year — the “mirror” of Suixing following the 12 Branch Division. All of the names indicate a yin, female, and inauspicious “star” that moves clockwise in the heavens. Feng shui practitioners know this as the Grand Duke. The Grand Duke corresponds to the Branch of the year. (The fact that the Grand Duke is female should not surprise you any more than the fact that Guanyin is actually male.)

Daiyin has always determined the auspiciousness of seasons and times (years, months, days, hours), but in the older systems it applied only to months. In the Huainanzi Taisui applied to the months and occupied only zi, mao, wu, and you on a liuren. (People tracked Daiyin around the celestial circle on a liuren.)

From early times, Posuixing and Taisui (Daiyin) were used for calendrical divination. Posui, Sui po and Posuixing all identify Suixing. The Wuxingzhan (c. 250 BCE) says that Suixing is the "male mate" of Daiyin. Posuixing is a yang, male, auspicious “star” that moves counter-clockwise in the heavens (as viewed from the Northern Hemisphere).

In feng shui, Posuixing is the “broken year” or “clash of the year” — that is, it opposes Daiyin across a liuren (and therefore in the Branches). Posuixing resonates with the Supreme Polarity.

Daiyin and Posuixing are not “intangible stars,” as has been claimed. They are related to ganzhi cycles of time, and to calendars that indicated these cycles. Daiyin originally mirrored the orbit of Suixing. Chinese sources indicate Daiyin and Posuixing were originally part of ancient calendars (perhaps as ancient as the Fire Calendar or Turtle Calendar). The calendars containing these “time-spirits” may have been combined sometime around the Warring States era (475-221 BCE). It is known that by the time of the Qin era, Daiyin’s movements were no longer tracked opposite those of Suixing.

Virtue, punishment, and the Grand Duke

In one of the Odes dated to the ninth century BCE, the Zhou complained that Tian (an old farmers deity identified with the celestial north pole) was capricious. The “bad” Tian punished indiscriminately, the “good” Tian rewarded without consideration of actual merit. If Tian gave rewards and punishments over the course of a year, this is suide (“virtue of the year”), which resonates with Posuixing; and suixing (“punishment of the year”), which resonates with Daiyin.

The three were tracked together in Xing-De calculations.

According to tradition, Posuixing and Daiyin are “employed” by Beiji, which is the constellation closest to the celestial north pole. Posuixing and Daiyin are also “deities” of Beidou, the celestial clock.

In the same way, Xing (Punishment) and De (Virtue) were tracked to “determine the conformity of the four seasons,” according to the Guanzi. Xing and De explain the ganzhi in space and time, in 20-year cycles around the liuren, but move differently (De can occupy the center position; Xing cannot.) At the end of the ganzhi cycle of 60 years they are back at their original positions, in jiazi, at the Branch occupied by Daiyin (Wood, which is the "punishment" of zi, Water). They shift annually (Xing on mao or wu, De on zi or you), seven days after the winter solstice.

The Chu Silk Manuscript says, “When Daiyin is in yang, suide is in yin.” Xing follows the destructive cycle but moves clockwise around the outside ring of a liuren astrolabe. It has ancient powers to control the year (for good or ill) through the ganzhi, just as the Grand Duke corresponds to the Branch of the year and exerts a powerful influence.

De follows the productive cycle but moves counterclockwise around the liuren. It is not baleful like Daiyin because it is yang.

Here is how the Hanshu recorded one Xing-De system:

Almanac for the year jiayin. Taisui is in yin, the Xing of the year is in si.

Taisui is in bingchen. The Xing of the year is in chen, the De of the year is in bing.

The Grand Duke = the restless dead

Centuries earlier than the Taichu calendar reform, astronomical lore about Daiyin apparently mixed with cultural restrictions on construction, moving, and marriage. People believed that anyone who turned the earth in a direction that corresponded to the position of Taisui would find "wriggling flesh" and incur bad luck.

The dead were a demonic menace to the living and must stay locked in the tomb. “Digging on the head of Taisui” meant to dig up the dead so they could inflict disease and misfortune on the living. Because the dead are yin, the Grand Duke had to be yin.

To avoid catastrophe, anyone planning a construction project consulted astronomers, calendar or fengshui experts about the "star’s" position.

Wars and the Grand Duke

Calculations of Daiyin and Xing-De were popular with military diviners, according to the Hanshu:

The yin-yang specialists [of the army] operate in compliance with the seasons. They calculate Xing-De, follow the striking of the Dipper, conform to the Five Conquests [wuxing] …

The staff of King Wu of the Zhou tracked the movements of Suixing during the conquest of the Shang. Wu stopped his army when Suixing threatened to move in an unfavorable direction. When the planet moved into the appropriate xiu he crossed the Huanghe and defeated the Shang at Muye, in the Zhou month 4 which was Xia month 2, on day jiazi (our 18 April).

Thus King Wu heeded the warning of the ancient texts:

During battle, one must avoid attacking the position occupied by Daiyin.

Military experts wanted an enemy to be positioned “before” (facing) Daiyin (the position of sui sha), thus “attacking the position occupied by Daiyin.” The Chinese army would be sitting on Daiyin and facing Suixing. By keeping to the Way, the army would easily conquer the enemy.

Interestingly, San Sha theory mentions a “pincer” movement, which could be an allusion to units attacking an enemy’s flanks, and might date this material to around the time of Sun Pin. Unfortunately, too little is known about military divination to know whether the texts are explaining particular ways to deploy army units.

References

Cheng Jian Jun and Adriana Fernandes-Gonsalves (1998). Chinese Feng Shui Compass: A Step by Step Guide. Jiangxi Science and Technology Publishing House.
Robert Eno (1990). The Confucian Creation of Heaven: Philosophy and the Defense of Ritual Mastery. SUNY Press.
Mark Edward Lewis (2006). Flood Myths of Early China. SUNY Press.
Michael Loewe (1984). The Term K’an-yu and the Choice of the Moment. In Early China 9-10.
Marc Kalinowski (1999). The Xingde Texts from Mawangdui. In Early China 23-24.
D.W. Pankenier (1984). Mozi and the Dates of Xia, Shang, and Zhou: A Research Note. In Early China 9-10.
Sun Xiaochun and Jacob Kistemaker (1997). The Chinese Sky During the Han. Brill.
Zhentao Xu, David W. Pankenier and Yaotiao Jiang (2000). East Asian Archaeoastronomy. Gordon and Breach.