The I Ching is one of the oldest Chinese classical texts and predates Taoism and Confucianism. The I Ching is usually considered to be a book of divination. This website is about the inner meaning of the I Ching; the process to awaken or unveil the Original Spirit or Higher Self. It is called the Taoist I Ching, because it explains the I Ching from the point of view of Taoism. It uses The Taoist I Ching by the 18th century Taoist master Liu Yiming, and a 2nd century Taoist manual of spiritual alchemy Cantong Qi (Triplex Unity) by Wei Boyang, to explain the I Ching. The poems and verses of the Cantong Qi are based on the symbolism of the I Ching.

After meeting genuine teachers all my doubts disappeared, so that for the first time I realized that the Tao of spiritual alchemy is none other than the Tao of I Ching, the Tao of sages is none other than the Tao of immortals, and that the I Ching is not a book of divination, but rather a study of investigation, of principles, fulfillment of nature, and arrival at the meaning of life. -- Liu Yiming (18th c. Taoist master)

The ninth-century Taoist master Lu Dongbin, a Confucian scholar who later became a mystic of high rank in the esoteric Taoist hierarchy and is one of the 'eight immortals', wrote of the I Ching:

Although the words are very clear, yet they are also very vague. The shallow may take the I Ching to be a book of divination, but the profound consider it the secret of the Celestial Mechanism.
-- Lu Dongbin, 9th c. Taoist master (introduction of The Taoist I Ching)

The Celestial Mechanism is a Taoist term referring to an internal psychological process that is symbolized in the movements of the heavenly bodies. When one knows that the I Ching is a manual about this process, the words are very clear. When one thinks that the I Ching is about divination, the words are very vague. The simplified Chinese characters for I Ching are 易 (yi - change) and 经 (jing - scripture).

Sun and moon make the changes. (日月為易)
-- Wei Boyang, Cantong Qi (Triplex Unity)

Wei Boyang suggests that the character 易 is made up of the characters for sun at the top and moon at the the bottom (the shape of the moon character is a little different but still has the same meaning). These characters are also part of the characters for yin and yang. The traditional Chinese characters show the meaning in another way. The right part of the character for yin(陰)— 侌 means cloudy now, symbolizing that the Higher Self is obscured by the thoughts going round in one`s mind. The meaning of I Ching is The Scripture of the Changes of Yin and Yang. The I Ching is about how to return to pure yang, so one needs to understand the meaning of yin and yang. Returning to pure yang starts with hexagram #24 Return:

Return means coming back. In the body of the hexagram one yang moves below a group of yins ䷗; this hexagram represents the return of yang. The way to do it involves working in sequence, restoring it gradually; one cannot restore it immediately, or even if one does restore it immediately it cannot be stabilized. This path is not difficult to know, but it is difficult to practice….. going from a single yang ䷗, until six yangs ䷀ are pure and complete. -- Liu Yiming, The Taoist I Ching, hexagram #24 Return.

The meaning of the I Ching cannot be described more clearly than in the following two quotes.

The light principle returns; thus the hexagram counsels turning away from the confusion of external things, turning back to one’s inner light. There, in the depths of the soul, one sees the Divine, the One.
-- I Ching, Wilhelm/Baynes edition, Commentary on Hexagram #24 Return

By turning around the light, one sees one`s higher Self; this is a six step process.

The holy man, who understands the mysteries of creation inherent in end and beginning, becomes superior to the limitations of the transitory. For him, the meaning of time is that in it, the stages of growth can unfold in a clear sequence. He is mindful at every moment and uses the six stages of growth as if they were six dragons (the image attributed to the individual lines) on which he mounts to heaven. -- The I Ching p 371, Wilhelm/Baynes edition, Commentary on hexagram #1, the Creative

Dragons can fly and spit fire; they are symbols for the yang breath of the firing times. The process of returning to pure yang, is also called the Firing Process or the Firing Times.

The firing process spoken of in the alchemical classics and writings of the masters is a metaphor for the order of practical spiritual work.
-- Liu Yiming (The Inner Teachings of Taoism)
The firing process is the sixty-four hexagrams, indicating modification of simple and ready knowledge and capacity to restore them to their innate goodness. The alchemical classics and writings of the adepts, amounting to thousands of volumes, do not go beyond the principles of the I Ching. -- Liu Yiming (Taoist I Ching, Mixed Hexagrams #43 Parting and #44 Meeting)

On one hand, fire stands for the yang energy of illumination; the illumination of the mind of Tao, which is conscious awareness.

Fire is a symbol of illumination; operating the fire means employing illumination. Illumination is the quality of awareness and perceptivity. If one can be aware, then one has the mind of Tao, and the spirit is knowing. If one can be perceptive, then there is no human mentality, and the mind is clear. -- Liu Yiming (The Taoist I Ching, Hexagram 55 Richness))

On the other hand, fire stands for extinction; the extinction of everything that opposes conscious awareness. This opposition refers to the (false) yin energy of the human mind or lower self; the pollution of acquired conditioning, compulsive habits, the six senses troubling one, and the seven  emotions running wild.

The method of action in spiritual alchemy is to burn away all the pollution of acquired conditioning. -- Liu Yiming (Taoist I Ching, Hexagram #7 ,The Army)
When mundane yin is stripped away, and the celestial yang is pure, the firing is sufficient. -- Li Daochun, 13th c. Taoist master (The book of Balance and Harmony)

The firing process, which burns away false yin and reaches a state of pure yang, requires a balance of yin and yang. Here, balanced yin and yang refers to firmness and flexibility being balanced, while pure yang refers to conscious awareness of the Original Spirit and false yin, to the mechanical awareness of the human mind.

Stabilize the will with firmness; do the work with flexibility.
Making the will firm and strong is setting up the crucible;
Gradually progressing in the work is setting up the furnace.
Firmness and flexibility are both used, without imbalance;
Having prepared, work the fire and the convergence according to the time. -- Liu Yiming, The Inner Teachings of Taoism

Taoist texts do no openly reveal the firing process or the celestial mechanism. There is a long tradition of secrecy; this knowledge was usually passed on by word of mouth.

Those who know, do not speak; those who speak, do not know.
-- Dao De Jing, Chapter 56
Treatises, classics and songs expound ultimate reality, but do not commit the Firing Times to writing. If you want to know the oral instructions and comprehend the mysterious points you must discuss them in detail with a divine immortal. -- Zhang Boduan, 11th C. Taoist master (Understanding Reality)

On this verse Liu Yiming comments:

It is not that the immortals and real people haven't spoken of the firing process, but what they say is not organized. If you do not meet an illumined teacher, who will indicate the order for you, you will not be able to know it. -- Liu Yiming (Commentary on Understanding Reality)

Even when attempts are made to explain it, it is still not sufficient because the firing process is extremely subtle and requires extreme alertness.

The Golden Flower is the Golden Pill (Elixir of Life). All changes of spiritual consciousness depend upon the heart. This wonderful charm, although it works very accurately, is yet so fluid that it needs extreme wisdom and alertness, and the most complete absorption and tranquility. People without this highest degree of wisdom and alertness do not find the way to apply the charm; people without this utmost capacity for absorption and tranquility cannot keep fast hold of it. -- The Secret of the Golden Flower, Chapter One

The Taoist I Ching and the Cantong Qi are all about the firing process.

This is really a guide to the firing process as one watches over the furnace; if students study and find out the facts in the hexagram Overseeing, then they can grasp most of the process of firing the gold pill (elixir). -- Liu Yiming (the Taoist I Ching, hexagram # 19 Overseeing)
The Can Tong Qi (Triplex Unity) sees the hexagrams #1 Heaven and #2 Earth as cauldron and furnace and hexagrams #29 Mastering Pitfalls and #30 Fire as the medicinal ingredients. Therefore the rest of the remaining 60 hexagrams stand for the firing times.
-- Yu Yan (13th c. Taoist master, Commentary on the Cantong Qi
The mystic pearl is the pearl of complete yang, something round and bright and unclouded; it is a different name for the Gold Elixir. When the firing process reaches its time, the pearl will naturally be formed.
-- Liu Yiming (Awakening the Tao

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Amida Buddha seated on the head of Guanyin Boddhisattva

The simplified Chinese characters

The traditional Chinese characters

Six dragons ( (Click to enlarge)

A dragon spitting fire represents the yang breath of the firing process.
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Fudo Myo-o — the immovable King of Light, symbolizing the mind of Tao engaged in the firing process (Unkei, 1195 AD. Jyōraku-ji Temple, Kanagawa, Japan)

Shiva and Pavarti in one body,
representing the balance of yin and yang ,
India, St. Louis Museum of Art, US
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Li Tieguai, one of the 'eight immortals',
with the pill of immortality