Basics · the ten stems

The Ten Heavenly Stems

Ten stems, and only ten: five elements, each in a yang and a yin version. Everything a stem does follows from those two facts plus its position on the ring. The table below is the whole component, computed rather than copied.

The four stems of your chart

The output expands each of your stems into its combination partner, what they transform into, its clash partner, its birth-stage branch, its lu and its blade.

The complete stem table

Combinations and clashes are mutual: Jia combines with Ji, and Ji combines with Jia.

StemElementPolarityCombines withTransforms intoClashes with
甲 JiaWoodYang己 JiEarth庚 Geng
乙 YiWoodYin庚 GengMetal辛 Xin
丙 BingFireYang辛 XinWater壬 Ren
丁 DingFireYin壬 RenWood癸 Gui
戊 WuEarthYang癸 GuiFirenone
己 JiEarthYin甲 JiaEarthnone
庚 GengMetalYang乙 YiMetal甲 Jia
辛 XinMetalYin丙 BingWater乙 Yi
壬 RenWaterYang丁 DingWood丙 Bing
癸 GuiWaterYin戊 WuFire丁 Ding

The five combinations and what each becomes

Stem combination is the only relation that merges two stems into one element. The transformed element is a published table and is reproduced as such.

PairTransforms intoThe two native elements
甲Jia + 己JiEarthWood + Earth
丙Bing + 辛XinWaterFire + Metal
戊Wu + 癸GuiFireEarth + Water
庚Geng + 乙YiMetalMetal + Wood
壬Ren + 丁DingWoodWater + Fire

Only four clashes: two stems have none

This is the detail most often misremembered: a stem clash is six steps apart on the ring, and Wu and Ji simply have no partner.

Stems with a clash partner8 — Jia Geng, Yi Xin, Bing Ren, Ding Gui
Stems without oneWu and Ji
Clash rulesix steps apart on the ring of ten

Read together, combination and clash give every stem its two partners: Jia combines with Ji and clashes with Geng, Yi combines with Geng and clashes with Xin, and so on. Wu and Ji have combinations but no clash partner, which is a structural fact about the table rather than a gap in it.

Birth-stage branch, lu and blade

Yang stems start their birth stage on the four generative branches Yin, Si, Shen and Hai; yin stems start on Wu, You, Zi and Mao and run backwards. This table is what determines the shape of the whole twelve-stages family.

StemBirth stage atRunsLuBlade
甲 Jia亥 Haiforward寅 Yin卯 Mao
乙 Yi午 Wubackward卯 Mao寅 Yin
丙 Bing寅 Yinforward巳 Si午 Wu
丁 Ding酉 Youbackward午 Wu巳 Si
戊 Wu寅 Yinforward巳 Si午 Wu
己 Ji酉 Youbackward午 Wu巳 Si
庚 Geng巳 Siforward申 Shen酉 You
辛 Xin子 Zibackward酉 You申 Shen
壬 Ren申 Shenforward亥 Hai子 Zi
癸 Gui卯 Maobackward子 Zi亥 Hai

Frequently asked

These are the questions specific to this page; broader conventions live on the methodology page.

Why do Wu and Ji have no clash partner?
Because a clash is six steps apart on the ring of ten and the two earth stems sit opposite each other twice over. It is a property of the table, not an omission.
Do five combinations always transform?
No. The transformed element is what the pair becomes when the conditions are met, and this site prints the table without asserting that the transformation happened in any given chart.
What is lu and what is blade?
Lu is the branch where a stem is at its official post stage, and blade is where it is at prosperity. Both are computed on the twelve stages, and both are listed here as positions rather than as omens.
Are the stems elements first or polarities first?
The element comes first and the polarity splits it in two, so the ten stems are five pairs. That is why a day master question is really two questions: which element, and which polarity.

Reference index

Every enumerable component of ba zi has its own page here. Each page is computed by the same engine and can be checked item by item — none of it is a personality table.