Yi (乙) is the second heavenly stem and the yin form of Wood. If Yi is your Day Master, it is the stem above your day pillar — the reference point the rest of your chart is measured against.
Yi Wood is the Yin form of Wood, one of the ten Day Masters. New to this? Start with what a Day Master is and how it is calculated.
Where Jia is the trunk, Yi is everything that climbs, spreads and flowers. The classical image is a vine: it does not push through an obstacle, it finds the edge of it and keeps going. That is not weakness. A vine outlives storms that bring down trees, precisely because it has nothing rigid to snap.
In practice Yi reads as adaptable, socially fluent and quietly persistent. It works well through people, borrows structure rather than building it, and is unusually good at making itself welcome. Yi rarely wins by force and rarely needs to.
The failure mode is entanglement. A vine that grows in every available direction ends up committed to none of them, and Yi charts often show someone who has kept too many options open for too long, or who has attached to a support that was never going anywhere. Yi's discipline is choosing what to climb.
Wood is produced by Water and controls Earth; Metal controls it and Fire drains it. For Yi this means Water is support and learning, Earth is wealth, Metal is pressure and authority, and Fire is expression. Yi handles pressure differently from Jia: Metal that would cut a tree simply prunes a vine, so a Yi chart often tolerates authority and constraint better than its yang counterpart.
These relationships are the Ten Gods (十神). They are not personality labels — they describe what another stem does to your Day Master when it appears in your chart. This table is generated from the same function the chart tool uses, so it matches what the calculator would tell you.
| Stem | Relation to Yi Wood | What it does to Yi Wood |
|---|---|---|
| Jia Wood 甲 | Rob Wealth 劫財 | Wood of the other polarity beside vine and flower — money leaves through people. |
| Yi Wood 乙 | Friend 比肩 | A true peer for vine and flower; a rival for the same ground. |
| Bing Fire 丙 | Hurting Officer 傷官 | vine and flower outputs Fire sharply — brilliance that cuts. |
| Ding Fire 丁 | Eating God 食神 | vine and flower outputs Fire easily — talent that flows. |
| Wu Earth 戊 | Direct Wealth 正財 | vine and flower works Earth steadily — earned in proportion to effort. |
| Ji Earth 己 | Indirect Wealth 偏財 | vine and flower works Earth in lumps — windfalls, not salary. |
| Geng Metal 庚 | Direct Officer 正官 | Metal shapes vine and flower — structure you accept. |
| Xin Metal 辛 | Seven Killings 七殺 | Metal cuts at vine and flower — pressure that asks no permission. |
| Ren Water 壬 | Direct Resource 正印 | Water feeds vine and flower steadily — support and schooling. |
| Gui Water 癸 | Indirect Resource 偏印 | Water feeds vine and flower unevenly — sideways insight. |
What each of the ten relations means in general — Direct Wealth, Seven Killings, Hurting Officer and the rest — is set out in the Ten Gods glossary.
Classical BaZi grades a stem by the season it was born into — the 旺相休囚死 scale. Wood peaks in spring, is supported in winter, and is at its weakest in autumn when Metal rules.
| Birth season | Grade | What it does to Yi Wood |
|---|---|---|
| Spring (寅卯辰 · Feb–Apr) | 旺 Peak | Peak season for the vine: fast, well-supported growth, with the usual risk of spreading in every direction at once. |
| Summer (巳午未 · May–Jul) | 休 Resting | Flowering and spending. Yi expresses easily in summer, but thin stems dry faster than trunks — Water is the limiting factor. |
| Autumn (申酉戌 · Aug–Oct) | 死 Weakest | Metal prunes rather than fells. Yi survives the season that breaks Jia, and often does its most disciplined work here. |
| Winter (亥子丑 · Nov–Jan) | 相 Supported | Dormant rather than dead. Support is present underground; visible progress waits for warmth. |
Wood corresponds to Green, the numbers 3, 8, and the direction East. These are traditional correspondences for the element itself. They are not a prescription — whether Wood is helpful to you depends on your whole chart, not on your Day Master alone.
3 March 1988, born in Taipei — day pillar 乙卯 (Yi Mao).
The day stem is 乙 and the birth month is 卯 — mid-spring, when Wood rules. This is Yi at seasonal peak, sitting on its own element. Strong Wood like this generally does not want more support; it wants somewhere to go, which usually means Fire for expression or Metal for structure. Again, the season tells you the tendency, not the verdict — the other six characters decide.
How the day pillar is derived — solar terms, true solar time and the late Zi hour — and what a Day Master cannot tell you on its own, are covered on what is a Day Master.
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