The stem branch, that is, the heavenly and terrestrial branches, originated from the observation of celestial phenomena in ancient China.

"A, B, C, D, E, G, G, XIN, NON, and QI" are called the ten heavenly stems, and "Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, and Hai" are called the twelve earthly branches.

The composition of the heavenly stem and the earthly branch formed the chronological calendar of ancient times, which is said to be the beginning of the Yellow Emperor's teacher.

The ten stems and the twelve branches are matched in turn to form sixty basic units, and the two cooperate with each other in a fixed order to form the Ganzhi Era Law.

In ancient times in Middle-earth, the sexagenary branch was mainly used for the chronicle of the day, in addition to the month, year, time, etc.

In ancient times, the ancients used the heavenly stem and the earthly branch as the carrier, the heavenly stem carried the way of the heavens, and the earthly branches carried the way of the earth.

Heaven and earth determine humanity, so the heavenly stem and earth branches are set up to fit the fortune of heaven and earth.

Heaven and earth are positioned, the stem branch is used to determine time and space, and time and space are used to determine the world.

Although all things are longer than the earth, the prosperity and decline of all things are inseparable from the sky. The combination of the ten heavenly stems and the twelve earthly branches forms the sixty jiazi, which is used to expound the study of heaven, earth and man.

The ancient brief said: "Rong Cheng makes a calendar, and scratches it to make a jiazi." "Judging from the ancient records, there were 12 earthly branches during the Yellow Emperor's period, all of which represent 12 different months and festivals every year;

Cadre branch is one of the important means and ways to apply easy learning in practice, and the development law of many things is recognized through it.

The word "dry branch" is derived from the "dry branch" of a tree.

The ten heavenly stems are: A, B, C, D, E, G, G, XIN, NON, and Dec; A, C, E, G, and Non are yang stems, and B, D, G, Xin, and Dec are yin stems.

The 12 earthly branches are:

Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai. Among them, Zi, Yin, Chen, Wu, Shen, and Xu are the yang branches, and Chou, Mao, Si, Wei, You, and Hai are the yin branches.

The 12 earthly branches correspond to the 12 zodiac signs:

Zi-rat, ugly-ox, yin-tiger, mao-rabbit, chen-dragon, si-snake, noon-horse, wei-sheep, shen-monkey, unitary-chicken, 戌-dog, hai-pig.

There is a cloud in the forefather: "The stem of the sky, the stem of the wood, is strong and yang, and the branch, the branch of the wood, is weak and is yin." It can be seen that the original intention of calling it a dry branch.

Since the meaning of the sexagenary branches comes from trees, their original meanings have also been given vivid expressions.

The trunk is like the trunk of a tree.

A: Like plants and trees breaking through the soil and sprouting, yang is enveloped by yin.

B: Plants and trees are primary, and the branches and leaves are soft and bent.

C: Bingye, like the great sun, scorching fire, everything is burning, seeing and bright.

Ding: Plants and trees grow strong, just like human beings.

E: Lush also, symbolizing the lush prosperity of the earth's vegetation.

F: Rise, discipline, all things rise from repression, tangible and disciplined.

Geng: What's more, the autumn harvest is waiting for the next spring.

Xin: The golden taste is spicy, the thing is made and then there is a taste, the spicy, the new, all things are solemnly changed, and the show is new.

Ren: Pregnancy, yang energy lurks in the ground, and all things are pregnant.

癸: Suddenly, everything is hidden, pregnant and underground, and it sprouts.

The branch is like the branch of the tree.

Child: Breeding, Yang Qi begins to sprout, and Breeding is born in Xiaye.

Ugly: New, the cold is self-flexing.

Yin: Yanya, Jinya, the bent grass and trees in the cold soil stretch from the ground in the spring sun.

Mao: Mao, the sun shines in the east, and everything is luxuriant.

Chen: Earthquake, stretch, all things are born from the earthquake, and the yang energy has been halfway through.

Si: Si also, the yang energy is already in the cloth.

Afternoon: Everything, all things are full and grown, yin and yang are stunned, yang is abundant, and yin begins to sprout.

Un: 眛也, the middle of the day is 昃, and the sun is secluded.

Shen: When the bundle is stretched, the body of all things is formed.

You: Yes, everything is ripe.

戌: Extinguish, all things are extinguished.

Hai: The nucleus is also the core of all things collected.

The twelve-earth branch glyph is derived from the ten heavenly stems.

Pregnant nail, called the child

Pregnant Geng, called ugly

B pregnant Ding, called Yin

B pregnant C, called Mao

I am pregnant, and I am Chen

Ding is pregnant, called Si

Ding is pregnant, called noon

Pentogeng, said not

Xin pregnant, called Shen

Xin pregnant Ren, called unitary

Pentoxin, called 戌

Decyl pregnant B, called Hai

The combination sequence is - yang stem with yang branch, yin stem with yin branch.

The 28 constellations of Zhou Tian are composed of stars, the stars are very stable, the relative position remains unchanged for tens of thousands of years or even longer, and the impact on the earth is also relatively stable, and the earth and other planets of the solar system continue to revolve around the sun, and the entire solar system is relative to the position of the North Star unchanged in the Milky Way to do spiral rotation, which forms a change in the position relationship between the stars due to the operation of the sun and the moon and the five stars, and then changes the impact of a specific star on the earth and everything on the earth, so the ancients predicted the good luck and evil by observing the sky at night, and the seven politics and four surplus and Ziwei Doushu are the extension of the ancient astrological life。

Stargazing at night is restricted by many unfavorable factors such as time, location, climate, etc., so people try to find a simpler way to divination, and the earthly branch is used in this situation.

The division of the months is based on the cycle of the moon, which is divided into large and small months, 30 days for the big month, 29 days for the small month, and 12 months for the year. Therefore, astronomically divides the ecliptic plane into 12 signs, and divides the 12 months into 12 months with the sun passing through the palace. Therefore, in ancient times, the twelve signs of the zodiac were named after the earthly branches, and the twelve palaces corresponded to the twenty-eight houses, that is, the womb had three houses, namely, the uterus had three houses: female, void and dangerous; the ugly palace had two houses of fighting and ox; the Yin palace had two houses of tail and kei; the palace of Mao had three houses: Di, Fang and Xin; Chen Palace had horns and two houses; the palace of Si had wings and two houses; the afternoon palace had Liu, Xing, and Zhang three houses; Wei Palace had two houses of well and ghost; Shen Palace had two houses of Ji and Shen; you palace had stomach, Pleiades, and Bi three houses; Xu Palace had two houses of Kui and Lou; and Hai Palace had two houses of room and wall. Therefore, the astronomical imagery of the 28 Nakshatras is the source of the imagery of the earthly branch in the Ganzhi Study, and there are 28 constellations hidden in the 12 earthly branches, and its meaning is also derived from this.

Because the stem branch is used for timekeeping, if the plane of the zodiac is imagined as the dial of the clock, with the earth as the center of the dial, the zodiac is the scale indication of the dial, and the sun and moon are equivalent to seven hands, running on the large dial of the zodiac, forming a huge clock. Among them, the sun is the "year" pointer, and the earth orbits the sun for a week and returns to the origin point is the time of a year; the moon is the "month" pointer, and the moon orbits the earth for a week and returns to the origin point is a month's time; the 24 solar terms are directly related to the sun's passing through the palace, but not directly related to the moon's operation, so it causes the time difference between the moon and the solar terms on the calendar, so the monthly order of the Ganzhixue is determined according to the solar terms, that is, it is consistent with the sun's passing through the palace.

The two slowest hands, the cycle of the conjunction of Jupiter and Saturn, the two most important planets in the solar system, take twenty years, or one movement, and sixty years, or one dollar, if the two stars are to meet in the same house.

In the same way, the period when the sun and moon coincide in the same house takes about 180 years, that is, a positive yuan, and if the position of the sun and moon coincides again, from a house with an angle of 30 degrees to a star with an angle of 12.8 degrees, it will take about 540 years to coincide once, that is, a great yuan. Because the twelve signs are the twelve earthly branches, which represent the twelve directions in space; the dial of the clock represents the energy field of the universe, that is, the aura of the relatively static heaven and earth; the movement of the sun and the moon and the five stars stirs up the originally relatively static energy field, and the position distribution of the sun and moon and the five stars in the twelve houses represents the influence of the stars on each house in the current time, that is, the distribution state of the energy of celestial bodies in the current time and space, and its expression forms are Jiazi, Yichou, Bingyin, Ding Mao, etc.

The rotation period of the earth is one day, that is, twelve hours, in the process of the earth's rotation, the influence of the sun and moon stars on the same place of the earth is changing from time to time, the same place on the earth has been in orbit relative to the sun and moon and the five stars, and the earth's rotation angle has advanced by about one degree in one day, that is, the spatial position of the sun and moon has changed by one degree, and the cycle has begun, day after day.

Therefore, the energy distribution of celestial bodies in the same place on the earth changes by one degree per day, that is, the energy distribution of the same place changes day by day and hour by hour, which is Jiazi, Yichou, Bingyin, Dingmao, and so on.

Why is there twelve earthly branches and only ten heavenly stems?

First of all, the clock model just now is based on the geocentric theory, and in fact, the earth and the other five stars are revolving around the sun, due to the difference in orbit and speed, resulting in the relative position of the planets between the orbit and the distance away, that is, the astronomical "planetary retrograde", retrograde has a special position in astrology, traditional astrologers believe that retrograde makes the planets exert a weak influence.

However, under the guidance of the theory of yin and yang in ancient China, according to the two forms of the five stars relative to the position of the earth, close and far away, the energy represented by the five stars is divided into yin and yang, and according to the energy of the five stars affecting the earth, it is sorted in order: A, B, C, D, E, G, XIN, NON, and Dec ten heavenly stems.

The heavenly stem and the earthly branch match, and there are two more earthly branches without the heavenly stem to match, forming the empty space, also called empty death.

This is due to the constant rotation and revolution of the sun, moon and the earth have stirred the energy field of the originally relatively static zodiac, which has caused the uneven distribution of energy around the earth, which is equivalent to the whirlpool formed by the river water in the downstream of the stone and behind the stone, and the position of this whirlpool is empty death.

With the passage of time, the position of the sun and moon changed, and the position of the vortex also changed, the original vortex disappeared, and the adjacent place became a vortex, and the cycle began again and again, and the cycle was one week, thus producing a reciprocating cycle of sixty jiazi.

The Ganzhi Calendar develops into the year, month, and time to form the Ganzhi calendar.

In addition to being used to record time and divination, the stem branch was later endowed with more and more functions.