Yin and yang

Meaning

Yin (陰) and yang (陽) first named the two sides of a hill: yin the shaded slope, turned to the north, yang the slope in the sun, turned to the south. From that plain image Chinese thought drew a way of seeing every pair that belongs together and turns into the other: shade and light, cool and warm, rest and movement, night and day, receiving and beginning, inward and outward.

They are not good and evil, nor two forces at war. Each needs the other to be what it is, each holds a seed of the other, as the two small dots of the familiar diagram show, and each turns into the other at its height: the longest night of the year turns towards the day, noon is the start of the afternoon. The Book of Changes puts it in six characters: “One yin, one yang: that is the Way.”

Yin and yang name a relation rather than a substance. A thing is yin or yang only beside another, and in one respect rather than in all: autumn is yin after the summer, yet less yin than the winter to come. That is why the tradition reads them in degrees and in movement, a lesser yang growing in spring, the greatest yang at midsummer, a lesser yin in autumn, the greatest yin at midwinter, and never as a fixed label on a person.

In practice

• In Ulune’s Chinese languages, every Heavenly Stem and every Earthly Branch is yang or yin in turn: Jia is yang Wood and Yi yin Wood, the Rat’s branch is yang and the Ox’s yin. A pillar of the sixty-cycle always pairs a yang stem with a yang branch or a yin stem with a yin branch, which is why there are sixty pillars and not a hundred and twenty.
• In BaZi, how a stem stands to the Day Master depends on its phase and on whether its polarity is the same or the other: the Ten Gods come in pairs this way. The luck pillars read polarity too: they run forward when the year’s stem and the birth’s count agree, both yang or both yin, and backward otherwise.
• The count is the tradition’s, which took it from a person’s sex. Ulune asks for it only as an option, keeps it with the chart on the device, never sends it, and shows both versions when it is left empty: the two directions of the luck pillars, and Feng Shui’s two Kua numbers.
• In Feng Shui, the Flying Stars of a home fly forward or backward through the nine palaces as the mountain that sets them is yang or yin.
• In the five phases, yin and yang give the cycle its shape: Wood and Fire are its rising, yang half, Metal and Water its gathering, yin half, and Earth the turning between them.

Across traditions

• Western astrology calls the fire and air signs masculine, or positive, and the earth and water signs feminine, or negative, alternating round the zodiac from Aries: Ptolemy already divided them so, and modern astrologers sometimes call the two groups yang and yin.
• Numbers split the same way in China as in the Pythagorean table of opposites that Aristotle records: the Book of Changes calls one, three, five, seven and nine the numbers of heaven, yang, and two, four, six, eight and ten those of earth, yin.
• Physics borrowed the image: in 1947 Niels Bohr chose the taiji for his coat of arms, with the motto Contraria sunt complementa, “opposites are complementary”, to stand for his principle of complementarity.

Origin and history

The characters keep the image of the hill: both carry the sign of a slope, 阝, beside clouds for 陰 and the rising sun for 陽, and the Shuowen Jiezi, the first great dictionary (c. 100), still defines yin as the shaded side, north of a hill and south of a river. As forces of nature the pair appears in the Discourses of the States, where an earthquake of 780 BC is explained by yang held down beneath yin. The Daodejing says that the ten thousand things carry yin on their backs and embrace yang, and the Great Commentary on the Book of Changes makes their alternation the Way itself; in the 3rd century BC Zou Yan’s school joined them to the five phases, and under the Han dynasty the pair became the grammar of all Chinese learning.

In the 11th century the philosopher Zhou Dunyi drew the Diagram of the Supreme Ultimate, in which the Supreme Ultimate moves and gives rise to yang, rests and gives rise to yin, and from the two come the five phases. The round diagram of two interlocking halves, each with a dot of the other, took its familiar form in Ming-dynasty books. In 1703 Gottfried Wilhelm Leibniz, shown the hexagrams by the Jesuit Joachim Bouvet, recognised in their whole and broken lines his own binary arithmetic.

How Ulune calculates it

Ulune gives each stem and branch the polarity of its place in the cycle, the odd places yang and the even ones yin: Jia, Bing, Wu, Geng and Ren among the stems, Zi, Yin, Chen, Wu, Shen and Xu among the branches, are yang. The yin or yang count of a birth is an optional field of the birth form; BaZi’s luck pillars and Feng Shui’s Kua number read it, and both versions are shown when it is not given. For the Flying Stars, each of the 24 mountains is yang or yin by its place in its palace: the first mountain of a cardinal palace is yang, the first of a corner palace yin.

Correspondences