The classical system that turns four pillar pairs into a governing structure — and how a deterministic engine classifies it, rule by rule.
A Bazi chart is not a list of four characters. It is a system with a centre of gravity — one element, one relationship, that organises everything else and decides which decades help and which ones fight. Classical Chinese astrology gives that centre of gravity a name: 格局（gé jú）— Pattern. Without it, a reading is a pile of observations. With it, the chart becomes an argument.
This article is about the Pattern method (格局法, ) of the 子平（Zǐpíng）— Zi Ping method tradition. We will define the term at the level of the individual characters, trace it back to its classical source, walk through the eight regular patterns and the two opposite ways a pattern is handled, then watch a deterministic engine classify a real chart — with every rule traceable to a text you can read for yourself.
The standard translation is "Pattern," but the Chinese words say more than one word of English can carry. Both characters are worth unpacking.
This is worth stressing because Bazi has another class of named indicators — the 神煞（shén shà）— Spirit-Killers, such as 华盖 (Canopy Star), 驿马 (Traveling Horse) and 桃花 (Peach Blossom). These are decorative by comparison. Classical method makes them subordinate to Pattern and Useful God: a star can shade a reading, but the Pattern decides what the reading is about. Confuse the two and you get fortune-cookie astrology that names symbols and misses the structure.
You do not choose a pattern. The calendar chooses it for you. The Zi Ping Zhen Quan (《子平真诠》, Zǐpíng Zhēnquán) — literally "True Interpretations of Zi Ping," written by Shen Xiaozhan (沈孝瞻) in the Qing dynasty — fixes the rule in its eighth chapter, and the sentence is the load-bearing beam of the whole method:
八字用神，专求月令，以日干配月令地支，而生克不同，格局分焉。财官印食，此用神之善而顺用之者也；煞伤劫刃，用神之不善而逆用之者也。当顺而顺，当逆而逆，配合得宜，皆为贵格。 "The Useful God of the Eight Characters is sought exclusively from the Month Branch. Match the Day Stem against the Month Branch, and because production and overcoming differ, the Patterns are divided out. Wealth, Officer, Resource and Eating God are the 'good' Useful Gods to be used forward; Killings, Hurting Officer, Rob Wealth and Blade are the 'not-good' Useful Gods to be used in reverse. Support when support is due, oppose when opposition is due — when the combination is fitting, every one of them becomes a noble Pattern." — Shen Xiaozhan, Zi Ping Zhen Quan, ch. 8 (On the Useful God), 据沈孝瞻原文
The procedure the sentence describes is mechanical, which is exactly why an engine can run it:
The Month Branch has a second classical name: 提纲（tí gāng）— the Leading Branch. 提 means "to lift," and 纲 is the main rope of a fishing net: lift the rope and every mesh opens. The Month Branch is that rope, and the rest of the chart is the net. This is the reason month-branch analysis comes first — not because the month "weighs more" in some arithmetic of scores, but because it establishes the frame within which every other pillar is read. A chart with a broken structure cannot be rescued by a good Hour Pillar; a chart with a sound structure can survive a poor one.
One clarification that trips up beginners: it is the Month Branch (the season), not the Month Stem, that determines the Pattern. The stem rides on top; the branch is the ground.
When the Month Branch yields one of the eight "ten-god" relations, the chart has a 正格（zhèng gé）— regular pattern. These are the eight zheng ge, and they are the backbone of Zi Ping method:
| Pattern | 汉字 | Month-Branch Ten God | Handling |
|---|---|---|---|
| Direct Officer Pattern | 正官格 | 正官 · Direct Officer | forward (顺用) |
| Seven Killings Pattern | 七杀格 | 七杀 · Seven Killings | reverse (逆用) |
| Direct Wealth Pattern | 正财格 | 正财 · Direct Wealth | forward (顺用) |
| Indirect Wealth Pattern | 偏财格 | 偏财 · Indirect Wealth | forward (顺用) |
| Direct Resource Pattern | 正印格 | 正印 · Direct Resource | forward (顺用) |
| Indirect Resource Pattern | 偏印格 | 偏印 · Indirect Resource | forward (顺用) |
| Eating God Pattern | 食神格 | 食神 · Eating God | forward (顺用) |
| Hurting Officer Pattern | 伤官格 | 伤官 · Hurting Officer | reverse (逆用) |
When two or more ten-gods appear in the Month Branch's Hidden Stems, the pattern is resolved by a fixed classical priority — Officer, then Killings, then the two Wealths, the two Resources, Eating God and Hurting Officer. This ordering is not arbitrary: it reflects which relationships carry the strongest structural claim on the chart. The engine that powers EchoReading's readings applies exactly this order, and the rule lives in a single auditable function rather than in the interpretation layer — so the classification is reproducible, not improvised.
The second half of the chapter quoted above is the engine of the whole system. It divides the eight gods into two teams.
This single principle generates every "formed" or "broken" verdict in the method. It is also the point where a chart stops being a label and becomes an argument: the Pattern names the force the chart is built on, and the handling rule tells you what that force needs in order to work for the native instead of against them.
Because the handling rule is explicit, the engine can grade the result. A Pattern is formed when the element its handling requires is actually present; broken when the wrong element appears instead; ordinary when neither shows clearly. The Zi Ping Zhen Quan devotes an entire chapter (ch. 9, 论用神成败救应 — "On the Success and Failure of the Useful God, and Its Rescue") to this, and one line captures the logic of rescue:
财本忌比劫，有食神则不忌而喜，盖有食神化之也。 "Wealth by nature fears Friend and Rob Wealth; but with an Eating God present it no longer fears them and even welcomes them, because the Eating God transforms them." — Shen Xiaozhan, Zi Ping Zhen Quan, ch. 9 (On the Success and Failure of the Useful God), 据沈孝瞻原文
The reading is subtle. A Wealth pattern is normally damaged by companions (比劫, Friend and Rob Wealth), who "divide the spoils." But if an Eating God — the Day Master's own output — is present, the companions' energy is channelled into that output, which then produces Wealth again. The threat becomes feedstock. This is why "broken" is never a verdict on a person; it describes a structural gap that a later Luck Pillar may fill.
Here are the engine's implemented rules for the main patterns, so you can see the logic as code rather than prose:
| Pattern | Formed when | Broken when |
|---|---|---|
| 正官格 Direct Officer | 财 (Wealth) or 印 (Resource) present | 伤官 present (伤官见官) |
| 七杀格 Seven Killings | 食神 controls, or 印 transforms | 财 feeds the Killings unchecked |
| 正/偏财格 Wealth | 食伤 (output) produces Wealth | 比劫 (companions) seize Wealth |
| 正/偏印格 Resource | 官杀 (Officer/Killings) feed Resource | 财 breaks Resource |
| 食神格 Eating God | produces Wealth | 偏印 seizes the food (枭神夺食) |
| 伤官格 Hurting Officer | paired with 印, or produces 财 | meets a 正官 |
Notice that every "broken when" clause is a relationship, not a curse — and every clause can be reversed by a favourable Luck Pillar. The pattern is a diagnosis with a treatment protocol attached.
Not every chart hands you a clean ten-god from the Month Branch. The classical method then looks further, but it keeps its priorities straight — the same text (ch. 29, 论时说拘泥格局 — "On the Pedantic Fixation on Patterns") is explicit:
八字用神专凭月令，月无用神，徐寻格局。月令，本也；外格，末也。 "The Useful God is determined solely by the Month Branch; when the Month Branch yields no useful god, one then seeks a pattern elsewhere. The Month Branch is the root; external patterns are the branch-tips." — Shen Xiaozhan, Zi Ping Zhen Quan, ch. 29, 据沈孝瞻原文
That priority statement rules out a lot of modern confusion. "Special" and "following" patterns are real, but they are the branch-tips, not the root. Three families of them matter:
When the Month Branch contains the Day Master's own stem or its same-element opposite — 比肩 (Friend) or 劫财 (Rob Wealth) — the chart is said to "stand on its own root." These are the 建禄格（jiàn lù gé） (Establishing Prosperity) and 月劫格（yuè jié gé） (Month Robbery) patterns. They are not weak charts; the question shifts to what the self-sufficient Day Master does with its force — ideally it is directed into Wealth, Officer or output.
At the opposite extreme, when the Day Master is so thoroughly unsupported that it has no independent standing — no Resource to feed it, no Companion to help it — the classical verdict is not "weak" but "follow." The chart is given over to the dominant force and is read through it: 从财格 (follows Wealth), 从官格 (follows Officer), 从儿格 (follows the "child," i.e. output), and 从势格 (follows the prevailing force). The engine tests for this with an explicit condition: the Day Master's element must appear at most once in the chart, and there must be zero Resource or Companion stems.
The hardest structure in the whole system is 化气格（huà qì gé） — the Transformation Pattern — in which a Heavenly Stem combination genuinely transforms into a new element (甲己化土, 甲 and 己 combining to Earth, and so on). Once transformed, the chart is no longer read through the original Day Master at all. It is a subject large enough for its own article; for now, note only that a serious implementation must model the classical breakers — 争合 (contending combination) and 妒合 (jealous combination) — because, as the Yuan Hai Zi Ping records, when those appear "the transformation does not form." A chart that merely contains a combination is not the same as a chart that is genuinely transformed, and telling them apart is where careless readings go wrong.
Classical Bazi is not a single doctrine. Two great traditions read the same chart from opposite ends, and honest software should tell you which one it follows.
Pattern-first, codified in Shen Xiaozhan's Zi Ping Zhen Quan: the Month Branch determines the Pattern first, and the Useful God is derived from what that Pattern needs. Day-Master strength is a supporting consideration.
Strength-first, associated with the Di Tian Sui (《滴天髓》, ): assess whether the Day Master is strong or weak first, then choose the Useful God that restores balance — supporting a weak Master or draining a strong one.
Our engine's ruling: we resolve the Useful God in the documented priority Climate Adjustment > Pattern > strength — that is, the season can override, the Pattern governs, and Day-Master strength breaks ties rather than leading. This is a declared choice, not a universal truth; a strength-first practitioner could reach a different verdict on the same data, and a reader deserves to know which lens is in use.
The Di Tian Sui has its own memorable formulation of the balance ideal, and it is the line that best explains why a "difficult" god can still make a great chart (ch. 中和论, "On Balance"):
有病方为贵，无伤不是奇，格中如去病，财禄两相随。 "Only a chart with an affliction can be noble; without damage there is nothing extraordinary. When the Pattern finds the cure for its affliction, wealth and rank follow together." — Di Tian Sui, chapter on Balance (中和)
In pattern language, the "affliction" is exactly the tension the Pattern describes — a strong body pressing on Wealth, or Killings with nothing to transform them — and the "cure" is the handling element that the chapter of the Zi Ping Zhen Quan on success and failure tells us to look for. The two traditions meet here: one names the structure, the other names the cure.
Abstract rules are easy to nod along to and hard to trust. So here is a real classification, produced by the engine that runs EchoReading's live readings. The birth data is 8 April 1995, 06:00 (clock time, no location correction for this demonstration).
| Year Pillar | Month Pillar | Day Pillar | Hour Pillar | |
|---|---|---|---|---|
| Stem | 乙 | 庚 | 己 | 丁 |
| Branch | 亥 | 辰 | 巳 | 卯 |
| Element | Wood · Water | Metal · Earth | Earth · Fire | Fire · Wood |
The Day Master is 己（Jǐ） — Yin Earth, the soil rather than the mountain. The Month Branch is 辰（Chén）, whose Hidden Stems are 戊 (Wù, Earth), 乙 (Yǐ, Wood) and 癸 (Guǐ, Water). Converted against the Day Master, those three produce the ten-gods 劫财 (Rob Wealth), 七杀 (Seven Killings) and 偏财 (Indirect Wealth). Applying the classical priority, the Pattern is the 七杀格（qī shā gé）— Seven Killings Pattern.
What has just happened is the classical principle in action. Left unmanaged, Seven Killings is pressure. Here, pressure flows into Resource, and Resource feeds the Day Master — the traditional 杀印相生（shā yìn xiāng shēng）, "Killings and Resource generating each other." The very force that would crush a fragile chart is converted into support. This is exactly the "reverse use" the eighth chapter predicted: oppose the difficult god, and even it becomes a noble Pattern.
Strip away the vocabulary and the Pattern method is an argument for order of operations. Most casual readings run the analysis backwards — they start from a personality impression and then hunt the chart for support. Classical Zi Ping runs it forwards: season establishes the frame, the frame names the Pattern, the Pattern dictates the useful element, and only then do the Luck Pillars get judged. Every later layer inherits its meaning from that one decision.
That is also why a deterministic engine is a natural fit for the method, and why we keep the classification in auditable code rather than in the narration layer. If the Pattern is the chart's structure, then the first thing a trustworthy reading owes you is a structure you can inspect — spelled out, cited, and repeatable from the same birth data every time.