I Ching vs Bazi and Qimen Dunjia: How They Relate

Before any comparison, two things should be stated plainly.

First, ​dating by layers​. The judgments and line texts are generally placed in the Western Zhou; the Ten Wings (彖傳、象傳、繫辭傳、文言傳、說卦傳、序卦傳、雜卦傳) were compiled later, and their attribution to Confucius is a traditional claim rather than a proven fact. As for wood, fire, earth, metal and water as a complete system of generating and overcoming, that took shape mainly from the Warring States to the Han — it is almost invisible in the wording of the Zhou Yi's core text, and many of today's "trigrams matched to five phases" readings come from later commentary and divination practice.

Second, ​the question of method's ownership​. Bazi as practised today and Qimen Dunjia are both far later than the Zhou Yi, and neither is taught anywhere in the Ten Wings. Saying they "come out of the I Ching" is a loose cultural claim, not a textual fact. What can be confirmed is this: they reuse concepts that the Yi tradition established. NPC Code works from the received Zhou Yi, referring mainly to Wang Bi and Zhu Xi (《周易本義》《易學啟蒙》); the other arts appear here only for comparison.

​Yin and yang.​ The Yi's own words:

一陰一陽之謂道。 —《周易・繫辭上》

NPC Code's plain-language explanation: the world moves by alternation — not a war between good forces and bad ones, but a rhythm of filling and emptying. Bazi and Qimen take this layer of polarity over as the basic axis of their own charts.

​The eight trigrams.​ 《說卦傳》 matches the eight trigrams with family members, body parts and natural images (heaven, earth, thunder, wind, water, fire, mountain, lake). These images support the reading of Hexagram 1, Qian, and Hexagram 2, Kun, all the way to Hexagram 64, Wei Ji — and they also become the spatial furniture of Qimen.

​The Later Heaven trigrams matched to the nine palaces.​ 《說卦傳》 describes an ordering of the trigrams arranged by season and direction (後天八卦). Later tradition set those eight trigrams on a three-by-three grid of nine palaces, the centre being the fifth palace (assigned no trigram), with each of the remaining eight palaces carrying one trigram. Almost all of Qimen Dunjia's work unfolds on that grid; the Zhou Yi's own casting uses no grid at all.

Shared concept	Zhou Yi	Bazi	Qimen
Yin / yang	line types, 《繫辭》	yin-yang of stems and branches	host/guest, auspicious and adverse structures
Five phases	mostly brought in by later commentary	core (生剋)	core
Eight trigrams	64 hexagrams = two trigrams stacked	barely used	eight gates, eight palaces
Nine palaces	not used	not used	the whole board
Time	the moment you ask	the moment of birth	the hour of the question

The cleanest way to keep the three apart is to look at the kind of question each was born to answer.

• ​I Ching (Zhou Yi):​ "What is the structure of this matter? What sort of action fits it?" You bring one question, cast, and read judgment, line text and image as a mirror for thinking.
• ​Bazi:​ "What are my long-term tendencies — temperament, strengths, patterns that recur over the years?" It is a portrait, not a reply to the email you got today.
• ​Qimen Dunjia:​ "At this hour and in this direction, how do the conditions on each side stand?" It leans tactical, and it is bound to time.

A plain analogy: Bazi is like reading your own habits; Qimen is like looking at this afternoon's weather and map; the Zhou Yi is like sitting across from an honest, blunt friend who describes your situation back to you and points out the next honest move.

​Question:​ "A smaller company has offered me a role. Should I accept now, or wait?"

​Method (as taught by NPC Code):​ three coins, heads = 3, tails = 2; a sum of 6 is old yin and 9 is old yang, and these change; 7 and 8 do not. Throw six times, starting from the bottom line.

​Result:​ Hexagram 3, Zhun (Difficulty at the Beginning), with the first line changing. With the first line changing, the resulting hexagram is Shui Di Bi (Holding Together). Following the rule that with one changing line you read the changing line of the original hexagram, we read the first line of Zhun, Nine in the first place (other schools also have ways of consulting the resulting hexagram alongside).

​Original text:​

屯：元亨，利貞。勿用有攸往，利建侯。 —《周易・屯・卦辭》

初九：磐桓，利居貞，利建侯。 —《周易・屯・爻辭》

​Plain-language reading (NPC Code's own words, not the original):​ this is a genuine beginning, and beginnings are tangled by nature; as long as you hold to what is upright, there really is something that can come of it. The judgment says 勿用有攸往 — this is not the time to set off rashly or hurry off into the distance; and it says 利建侯 — it is better first to establish a foundation and settle on the people who will support you. The first line pictures hesitating and circling in place, and says that right now "staying put and holding to what is upright" is what serves you; its 利建侯 can be understood here as: first build up the foundation and the human conditions, and only then discuss going or staying.

​Concrete action:​ don't refuse outright, and don't rush to sign. Put the terms you are still unclear about in writing and ask, state your two real bottom lines, and set yourself a decision date. What 利居貞 hints at is this: whether the position you stand in is sound matters more than how fast you move — it is not a verdict that the job is wrong.

Notice what the Yi did ​not​ do: it did not predict the company's future, nor tell you what your fate holds. Bazi would not answer this question at all; Qimen would answer a narrower one, about timing.

Three habits keep the lines clean.

1. ​One question, one method.​ If you are going to ask the Zhou Yi, read the Zhou Yi. Piling three systems onto one worry usually just produces noise, and lets you pick the answer you already wanted to hear.
2. ​Label the layers clearly.​ The judgments and line texts are Western Zhou text; 《說卦傳》 belongs to the Ten Wings layer; matching trigrams to five phases and to the nine palaces belongs to later tradition. Six-line Na Jia (六爻納甲) and Plum Blossom (梅花易數) are later methods: Na Jia assigns five phases, stems and branches, and the six relatives to the lines; Plum Blossom takes its images from trigram five phases and the generating-overcoming of body and function, without using stem-branch Na Jia — they are legitimate arts, but not what the Zhou Yi's own text is doing.
3. ​Treat the language of fortune as description, not sentence.​ 吉, 凶, 悔, 吝, 无咎 speak of the texture of a situation and the cost of an action. 无咎 means roughly "nothing blameworthy here" — permission, not a guarantee. None of the three arts should replace a qualified professional for medical, legal or financial decisions.