I Ching, Yijing or Zhou Yi
"Oracle of the moon": © 2000 LiSe
Yi Jing, Oracle of the Moon

What are the potential and qualities of this situation?
Kūn, Space. Her image is Earth. Kūn is the embracing mother. She is nurturing, receiving, and focused on results. She is the place one calls home, one's territory. One obtains good fortune. The Earth trigram is like a womb, rich in possibilities, she can nurture things into concrete existence, like a crop, creatures, tangible resources like money, return on investment, but also dreams and visions that seem unattainable.
She accepts everything, organic or inorganic, and works with it. Proceeds it, nourishes it, arranges all creatures and objects around each other.
Many of her creations will perish, many will thrive, but the earth goes on. She has no empty spaces, no end or start, no goal or limit. She is strict and that way creates a balance that restores itself over and over. Things that strive to be perfect. Living creatures seeking health, water free to run, and sunshine free to enter. She fills even the darkest places with organic and inorganic creations.
土命 Tǔ Mìng, earth name/destiny: born in an earth year or having a local
or popular name - a lasting link to Earth.
What is the subject, intention or hope of your question? And what is your power in this?
Gěn, 'ward off'. His image is Mountain. He is high but does not boast, is strong but does not force anyone. Gen may be grumpy or a recluse but has a good heart and cares. Gěn is about individuality, staying true to yourself even when it is difficult and giving in would be easier. Gěn stands high above the valley below and seems aloof, but the mountain shelters and feeds the valley, makes the clouds release their water and sends it down to the vegetation and all creatures at its foot.
What do you want or need to do, what can you truly do, or what will fate unfold in this situation?
When Kūn activates Gěn: adapting to the Earth and yet staying oneself. Both Kūn and Gěn are what they are and do what they do, they support and open space for change but never think about it, never boast. Mountain solidifies all that Earth creates: matter, creatures and mind, each in its own unique image. Both are relentless in their own way, the two huge forces that create life and lend it its endurance.
Mountain's relation with Earth brings constancy in a world where anything can happen. And it will, time after time. They bring what is called eternity. By working with them, using the powers of Earth as the basis and the structure of Mountain to turn things into reality, one can create lasting values out of ideas, solid structures out of visions.
Kūn and Gěn are the 'origin' of hexagram 15. First trigram is the upper trigram (called '悔 huǐ, regret' or 'consult': the problem that makes you consult the oracle). Second trigram is the lower or inner trigram (called '真 zhēn, true': the answer of the oracle for this situation: the advice how to deal with it).
The upper line of Earth activates Gen the mountain. Like the mountain, one can rise from below and become visible through the creativity of Earth. The mountain brings steadfastness. Visionary ideas can now become viable plans with a lasting character. Everything that grows from the earth inherits her powerful care for its survival. The mountain represents this indestructible power, built from the earth as it is. Make use of it!
General: when a yang initiative joins the yin potential of surroundings or a time, its clear and strong ideas will stand out by their own merit. Yang can initiate the change that ensures that ideas and the work that has been done so far gain clarity and structure. This is a good time to develop visions and plans with creativity and enthusiasm. To put energy into your projects and to show them. Now you have the power to ward off evil or insecurity, a power that is part of yang.
Yang brings inspiration and joy, but yang also means that you have to put in effort or money in what you aim for. It can drain your resources, but decisions can be made; progress or new ideas can be shown.
The timing of this initiative: (Time can refer to the seasons of the year, the hours of a day, the progress of an undertaking, a state of mind - anything that has a beginning, a peak, a decline, and an end. See "Timing")
春生夏长, 畅茂条达, 富有之象也。
秋得则万物告成, 升虽不足, 而内实有余。
冬得之则草木凋零, 随毁随誉, 骤落骤荣, 旋消旋长, 而聚散无常。
Spring begins and summer grows, lush and unfettered, rich indeed is its sight.
When autumn is reached things are completed. Though from the outside not enough, (there is) within however certainly enough.
When winter is reached the crop withers. Slander and praise follow one another, time after time degradation is followed by fame, and increase and decrease turn their circle. Meeting and parting are irregular.

The Earth-line is stationary yin. This line is the subject, or the ‘field’ where you pour in or find both the cause and the means for your initiative: space, material, helpers or other people, resources and realization, even food for thought. It is a 'receiving' line, the earth needs input and resources to make things grow and bring concrete results.
Your subject or project will stay attractive, but it will continue to absorb and process and use it to continue the work. It will not shine on its own or show increase to the outside, the work of building up happens in the background, making your vision concrete, or whatever comes your way.
Beauty comes from the space within.

The middle line indicates the result. It is unchanging yin, this project will stay attractive, but also continue to absorb efforts, knowledge or resources, because its developing stage is not finished and not all possibilities have been explored. It still needs input and keeps doing so for the time being. It is too early to decide about a final direction, there will be no output yet, but its presence will be solid.
Yin is the one who can bring about concrete results. Yin stays in the background and does the work. It is nurturing, defusing crises, monitoring the process, building up and rounding out.
This is the 'man' line (not 'male' but human), it can also be about you yourself, not only what you do.
Love for the work dissolves the effort.
An activated Yang line is generally bright and giving.Yang is great for enthusiasm and spreading joy or success, for structure, but don’t expect solid results.
An activated Yin line generally does the work. Yin's creativity absorbs and converts resources into tangible results. It brings peace, beauty, and a sense of security.
The initiative (top line or Heaven line) is the intention or focus. Your ideas, plans, or what you want, or something that happens and you want to influence it or use its possibilities.
In this answer the line is activated
Yang: the initiative is clear and strong, this is a good time to develop visions and plans, pouring in creativity, efforts and enthusiasm.
The subject (bottom line or Earth line) is the 'reality' of your question or the ‘field’ of action. A situation or person, resources, materials, facts.
In this answer the line is stationary
Yin: She is the most difficult to influence, she is careful and follows her own creativity and decisions, but she is the one who turns resources into concrete results.
The outcome (middle line or Man Line) is what you or others or fate cause to happen 'between Heaven and Earth'. It is the outcome of this question. It can be physical or mental or both. If this is a yes/no question, then yang means yes, yin means no or 'not yet'. Both can be good or bad, depending on the question.
In this answer the line is stationary
Yin: good for concrete results. More work is needed, but your dedication is not in vain. For now, it will reduce the 'shine' because it focuses on creating, on growing something of quality, not on how it will look.
About the 3 lines of the trigrams and the spirit helpers:
Each line, active or at rest, summons one of the 8 trigrams as a Helper. For an activated line: telling you what you need - or about a problem area or something to avoid.
For a stationary line: this is what you already have or do or what you don't need. Often we just need a reminder of our abilities. Or it could be what you wish or fear - but will not happen.
Active lines are the helpers to change things, they listen to intentions, which can come from you, surroundings, or fate. Stationary helpers are part of the core meaning, they are your soul talking, but they also see the impossibilities or what is lacking at the moment. They reinforce the overall power of a reading.
Helper for the initiative: Gen, Mountain with his constancy, his ability to make things endure
Helper for the subject: Zhen, Thunder with his energy and stimulation and quick actions, is lacking here or not needed. Yin remains Yin.
Helper for the outcome: Kan, Water, with his direction and focus, his courage to take risks and his talent to give things shape, is lacking here or not needed. Yin remains Yin.
But when things are not satisfying, it might be that one or more helpers don't help enough - or try too hard. Or maybe you don't listen carefully enough.
This oracle is NOT according to the Neigua Chuwaili, a chapter of the Heluo Lishu, which is meant to be read and used in Chinese astrology. But I found beautiful texts about the trigrams in the Neigua Chuwaili and borrowed them for this trigram oracle.
For those who are interested in the Heluo Lishu see the course by Harmen Mesker.
See also "Yijing astrologie" by Harmen Mesker (Dutch).
The guide to calculating your birth hexagram.
For divining with trigrams, see the video by Tin Yat Dragon