BaZi Compatibility Basics

BaZi compatibility (合婚) compares two charts. It is often reduced to a single score, but a careful reading looks at several layers and treats the result as a description of dynamics rather than a verdict.

Layer 1: the two Day Masters

How does one Day Master relate to the other? Stems that combine (甲己, 乙庚, 丙辛, 丁壬, 戊癸) are traditionally read as natural attraction. A producing relation suggests support in one direction; a controlling relation suggests one partner shapes the other. Same element suggests peers.

Layer 2: the day branches

The day branch is the "spouse palace". Compare the two:

• Six combination or three-harmony — traditionally harmonious.
• Clash — friction or distance, especially around home life.
• Harm or punishment — subtler strain.

Layer 3: mutual useful elements

The most meaningful layer: does each chart supply what the other needs? If one chart's useful element is water and the other is full of water, the second partner tends to be experienced as supportive. If both need the same scarce element, they may compete for it.

Layer 4: timing

Compare luck pillars. Two people whose demanding decades coincide may feel strain from circumstances rather than from each other.

What compatibility cannot do

It cannot say whether a relationship will last, and it should never replace communication, shared values or professional advice. Many traditional "incompatible" pairings are simply different. Use the compatibility pages as a vocabulary for discussing dynamics, not as a test.

Before comparing: get both charts right

Compatibility depends on two accurate charts. Confirm each birth time, city and time zone, and check the hour pillar with true solar time. If one birth time is unknown, compare only the year, month and day pillars and say so — the day branch, which matters most for partnership, is still available. The compatibility calculator computes both charts with the same rules so the comparison is consistent.

The Day Master relationship in detail

The five possible relationships between two Day Masters each have a traditional flavour:

These are tendencies only. A controlling relationship can be stabilising if the controlled Day Master is strong; a producing relationship can be draining if the producing Day Master is weak.

The spouse palace and the spouse star

Classical compatibility looks at two things in each chart. The spouse palace is the day branch. The spouse star is traditionally Wealth in a male chart and Officer in a female chart. Many modern practitioners apply the palace analysis to everyone and treat the star rule as one traditional convention among several. Whatever approach you use, apply it consistently to both charts.

Check the day branches against each other with the relations table. A 子 and 丑 pair is a six combination; 子 and 午 clash; 子 and 卯 punish; 子 and 未 harm. Then look at what each day branch hides: a clash between two branches that both hold a person's useful element is more significant than a clash between neutral branches.

Mutual useful elements: a worked approach

1. Find each person's useful element.
2. Count how strongly the other chart contains it — visible stems, hidden stems and the month branch.
3. Note whether either chart is rich in the other's unfavourable element.

If each chart supplies the other's need, the pairing is traditionally described as mutually supportive. If one supplies and the other does not, the relationship may feel uneven. If both are heavy in what the other should avoid, practitioners advise extra awareness rather than declaring the match unsuitable.

Year branches and zodiac matching

Popular compatibility often compares only the year branches — the twelve animals. In BaZi this is the least important layer: the year branch reflects background and social environment, not the self. This site does not publish animal-sign matching; the year pillar is read with the others.

Timing in a relationship

Lay out both sets of luck pillars side by side. Mark decades where either person enters an unfavourable period or where a luck branch clashes their own day branch. Overlapping difficult decades suggest planning and patience; periods where one partner is supported can be times when that partner carries more. The annual pillars of the same year can be checked for both charts with the annual pillar calculator.

Common mistakes

• Treating a clash as a verdict. Clashes describe movement, and many lasting partnerships include them.
• Comparing charts built with different rules — for example one with true solar time and one without.
• Ignoring strength. A combination between Day Masters matters less if one of them is extremely weak.
• Using compatibility to make decisions for other people. It is a reflection tool for the two people involved.

Frequently asked questions

Is there a single compatibility score? Scores summarise selected factors and hide the reasoning. This site shows the layers instead.

Can compatibility be used for business partners? Yes; the same layers apply, with less emphasis on the spouse palace and more on Wealth and Officer.

What if one birth time is unknown? Use the three known pillars and treat hour-dependent conclusions as open.

A one-page comparison template

Fill in both columns from each person's chart, then write two or three sentences on the dynamics you see. The aim is a balanced description that both people would recognise, not a ranking.

A worked example

Consider two charts. Person A is a 甲 wood Day Master born in an 酉 month, weak, with water as the useful element. Person B is a 癸 water Day Master born in a 子 month, strong, with wood and fire as useful elements.

• Day Masters: 癸 water produces 甲 wood. B supports A.
• Useful elements: A needs water, and B's chart is rich in water. B needs wood to drain excess water, and A is a wood Day Master. Each supplies what the other needs — the most favourable pattern in traditional terms.
• Day branches: suppose A's day branch is 午 and B's is 子. These clash. The classic reading is friction in daily life and home, even when the deeper elemental fit is good.
• Timing: if A is in a metal luck pillar (pressure on wood) while B is in a fire pillar (B's useful element), B may be the steadier partner during those years.

A balanced summary might read: "Strong mutual support at the level of elements; day branches clash, suggesting differences in routines or living arrangements; A's current decade is demanding, B's supportive." This is far more useful than a single score.

Discussing a reading with both people

If you read compatibility for others, present it to both people together, state the method and its limits, and invite them to say which descriptions fit. Avoid statements that predict breakups or label one person as harmful to the other. The BaZi FAQ covers common questions about accuracy and use.

Key points

• Compatibility compares two accurately computed charts layer by layer. It is not a single score.
• Layer 1 is the relation between the two Day Masters: same element, producing, controlling, combining or clashing.
• Layer 2 is the day branches (the spouse palaces): combination, clash, harm or punishment.
• Layer 3, often the most meaningful, is whether each chart supplies the other's useful element.
• Layer 4 is timing: compare luck pillars to see when either person is in a demanding decade.
• Year-branch (animal) matching is the least important layer in BaZi and is not used on this site.
• Present readings to both people together, state the method and its limits, and avoid verdicts.
• A clash describes movement and difference. It is not a prediction of failure.

Key terms in this article

Stem Combination · 天干五合

Five pairs of stems combine: 甲己 (earth), 乙庚 (metal), 丙辛 (water), 丁壬 (wood), 戊癸 (fire). Combination binds the two stems; whether they actually transform into the new element depends on the month and support, and many combinations only bind.

Six Combinations · 六合

The six branch combinations are 子丑, 寅亥, 卯戌, 辰酉, 巳申 and 午未. They bind two branches, which can weaken a clash on either branch. Transformation, as with stems, needs supporting conditions.

Branch Clash · 地支六冲

Branches opposite each other clash: 子午, 丑未, 寅申, 卯酉, 辰戌, 巳亥. A clash shakes both branches and their hidden stems. Clashes from luck or annual pillars to the day or month branch are traditionally watched closely.

Useful Element · 用神

The useful element (用神) is the element that best brings the chart toward balance or serves its structure. Schools differ: some choose by strength (support the weak, drain the strong), others by climate (warm a cold chart) or by structure. It is a conclusion of analysis, not something read off one pillar.

Next: Wealth and Officer stars.