Stem Clash — 天干相冲 tiān gān xiāng chōng

Look for clashes between your stems and the stems of luck and annual pillars.

Open the free BaZi calculator or the related tool to see Stem Clash applied to a real birth chart.

Stems and branches do not sit in isolation; fixed pairs and groups attract or oppose one another. Combinations (合) bind, clashes (冲) shake, harms (害) spoil a combination and punishments (刑) describe friction. These relations are listed mechanically, but their weight depends on distance, season and whether the elements involved are useful or unfavourable.

Adjacency matters. Relations between neighbouring pillars (year–month, month–day, day–hour) are read as stronger than those between the year and hour. A combination can also neutralise a clash: if 子 is bound by 丑, a 午 clash on 子 is weakened.

Most relations become active in time, when a luck or annual pillar brings the missing partner. That is why the same natal branch can be quiet for decades and then prominent in one particular year.

• Assuming every combination transforms.
• Treating every clash as a disaster.
• Ignoring distance between pillars.
• Forgetting that luck and annual pillars can complete a relation.

Combination and clash tables appear throughout the classical literature and in almanac traditions; the core lists are stable, while interpretation of transformation varies between commentators.

• Stem CombinationFive pairs of stems combine: 甲己 (earth), 乙庚 (metal), 丙辛 (water), 丁壬 (wood), 戊癸 (fire).
• Branch ClashBranches opposite each other clash: 子午, 丑未, 寅申, 卯酉, 辰戌, 巳亥.
• Six CombinationsThe six branch combinations are 子丑, 寅亥, 卯戌, 辰酉, 巳申 and 午未.
• Three HarmonyThree-harmony frames join three branches four positions apart into one element: 申子辰 water, 亥卯未 wood, 寅午戌 fire, 巳酉丑 metal.
• Directional CombinationDirectional (seasonal) combinations gather the three branches of one season: 寅卯辰 east wood, 巳午未 south fire, 申酉戌 west metal, 亥子丑 north water.

The fastest way to understand Stem Clash is to look at real charts rather than memorise rules. Enter a birth date, time and city in the BaZi Calculator, then locate where Stem Clash appears: in a visible stem, hidden inside a branch, in the current luck pillar or in this year's annual pillar. Note the position, because the year pillar is usually read as background and early life, the month pillar as environment and career setting, the day pillar as the self and close partner, and the hour pillar as later life and output.

• Compare two or three charts where Stem Clash is prominent and two where it is absent; write down what differs in the overall balance.
• Check the month branch first: seasonal strength changes how much any factor matters.
• Use the hidden-stems and Ten Gods tables in the calculator output instead of guessing.
• Treat single factors as clues, never as verdicts; classical texts always weigh the whole chart.

Different schools describe Stem Clash with slightly different emphasis. This site follows widely used conventions (solar-term months, true solar time optional, Zi hour setting configurable) and states them openly so you can compare results with a book or another calculator.

Stem Clash is one piece of a larger system. If you are learning BaZi from scratch, the order below builds each idea on the previous one, and every step links to free reference pages on this site.

1. Calculate a chart and confirm the four pillars are correct (checklist).
2. Learn the ten heavenly stems and twelve earthly branches.
3. Find your Day Master and judge its strength with the five elements.
4. Read the Ten Gods in context.
5. Move on to timing with luck and annual pillars.
6. Use the glossary whenever a term is unfamiliar.

BaZi is a traditional cultural system. This page explains how the symbols are defined and read; it does not make scientific claims or predictions about your health, money or relationships.