"We're 78% compatible" — that is not how compatibility works in BaZi. The system has no single number: there are several layers of interaction between two charts, and a couple can shine on one layer while feeling tense on another. This guide is a step-by-step method — exactly what masters compare, in what order, and how to read the result.
1 Step 1. Day Masters: the chemistry of two "selves"
The first layer is the relationship between your Day Masters 日主 (rì zhǔ — "master of the day"): the elements the partners "are." Wood and Fire feed each other (one ignites the other), Metal and Wood control each other (one cuts the other), two Earths are rivalry or brotherhood. A special case is Stem Combination 天干合 (tiān gān hé — "combination of stems"): pairs like 甲己 (jiǎ-jǐ) or 丁壬 (dīng-rén) literally "stick together" — a strong pull that, on its own, says nothing yet about the quality of life together.
2 Step 2. Day branches: the Spouse Palaces
The earthly branch of the day pillar is the Spouse Palace 夫妻宮 (fū qī gōng — "palace of husband and wife"), the place where the chart "stores" the partner. Look at how the two branches interact:
| Interaction | Signs | What it means for the couple |
|---|---|---|
| Combination 六合 (liù hé) | 子丑, 寅亥, 卯戌, 辰酉, 巳申, 午未 | The best sign: the palaces "embrace," partners naturally complement each other's daily life |
| Three Harmonies 三合 (sān hé) | 申子辰, 寅午戌, 巳酉丑, 亥卯未 | Allies by element: shared goals, teamwork |
| Clash 沖 (chōng) | 子午, 丑未, 寅申, 卯酉, 辰戌, 巳亥 | The classic "magnet-and-sparks": passion with conflict; needs maturity, not flight |
| Punishment 刑 (xíng) | 寅巳申, 丑戌未, 子卯… | Chronic friction over small things; treated by dividing zones of responsibility |
| Harm 害 (hài) | 子未, 丑午, 寅巳… | A quiet erosion of trust; the couple needs honest conversations, not guesswork |
Important: a clash of palaces is not a life sentence. It's a diagnosis of the relationship's style: such couples live vividly and argue loudly, and they're helped by a buffer — separate work schedules, their own spaces, a third, mediating element in the home and habits.
3 Step 3. Elemental balance: how you heal each other
The most underrated layer. Every chart has a Useful God 用神 (yòng shén — "useful god") — the element the chart lacks for balance. The strongest unions are where the partner is your needed element: for a weak Fire freezing in a winter chart, a "water" partner will snuff out what's left, while a "wood" partner will feed the fire. The check is simple: compare both people's 用神 with each other's Day Masters.
4 Step 4. Relationship stars
On top of the structure, look at the stars: Peach Blossom 桃花 (táo huā — "peach blossom") — charm and flirtation risk, the marriage star in her positions; the Lonely Star 孤辰寡宿 (gū chén guǎ sù) — a need for personal space. If both have a strong 桃花, the couple needs agreements about boundaries; if one has a "lonely star," the other shouldn't read it as coldness.
5 Step 5. Period synchronicity
The last layer is time. Take both people's Luck Pillars 大運 (dà yùn — "pillars of luck") and look at the next ten years: if one is in a rising period and the other is "wintering," the couple faces an asymmetry (one pulling ahead while the other recovers) — better to know this in advance. In practice, the most stable marriages aren't "perfect charts" but pairs with compatible schedules of strong and weak years.
6 How to put together the conclusion
1. Day Masters: feeding/control/combination — the basic chemistry.
2. Spouse Palaces: 合 is a plus, 沖/刑/害 are zones to work on.
3. 用神: does each partner give the other their element — the "healing" quality of the union.
4. Stars: temperaments and boundaries.
5. Periods: are the next ten years in sync.
The result isn't a percentage — it's a map of the union: where the couple has support and where things are thin. With this knowledge, "difficult" compatibility often lasts longer than "ideal" compatibility — because it knows its own thin spots.
Check your couple across all five layers
A complete compatibility reading: Day Masters, Spouse Palaces, both partners' Useful Gods, relationship stars, and period synchronicity — with practical recommendations.
Calculate CompatibilityRelated readings: marriage in BaZi, when to expect a partner, why the "wrong" partners get chosen.