乙庚合

The Yi–Geng Combination in a BaZi Chart

Yi–Geng (乙庚合) is a Heavenly Stem combination pairing Yi (乙) with Geng (庚), traditionally associated with Metal. Recognizing the pair and judging a transformation are distinct parts of interpretation. The first identifies two stems and their relationship; the second concerns how that relationship operates within the surrounding chart.

A BaZi pillar contains an upper Heavenly Stem and a lower Earthly Branch. Yi–Geng concerns the upper characters. Their locations matter because the year, month, day and hour pillars give each stem a particular position. The Day Master, taken from the day stem, supplies a second reference: it determines the Ten God name assigned to each other stem.

For the example dated 1990-06-15 at 14:30, female, the four pillars are 庚午 · 壬午 · 辛亥 · 乙未. Geng occupies the year stem and Yi occupies the hour stem. Ren (壬) and Xin (辛) stand between them in the month and day positions. The Day Master is Xin Metal. The Four Pillars guide explains these positions, and BaZi basics introduces their vocabulary.

Relative to Xin, Geng is Rob Wealth (劫财), while Yi is Indirect Wealth (偏财). These names express each stem’s relationship with Xin. “Yi–Geng combination” expresses a relationship between Yi and Geng themselves. The same characters therefore participate in two kinds of comparison: each with the Day Master, and the pair with one another. Keeping the reference point visible makes the terminology easier to follow.

A common misconception

The presence of Yi and Geng does not mean that the pair has transformed into Metal. In this chart, the two stems retain their individual identities in the reading: year-stem Geng as Rob Wealth and hour-stem Yi as Indirect Wealth. The traditional Metal correspondence names the combination’s associated element; a completed transformation requires a fuller judgment of the chart.

Stems, branches and hidden contents

The lower characters add concrete context. The year and month branches are both Wu (午), each containing Ding (丁) and Ji (己). For Xin, Ding is Seven Killings (七杀), and Ji is Indirect Resource (偏印). These hidden stems explain why a pillar’s visible stem gives only part of its contents. Beneath year-stem Geng sits a branch containing Fire and Earth stems.

The day branch Hai (亥) contains Ren (壬) and Jia (甲), respectively Hurting Officer (伤官) and Direct Wealth (正财) for Xin. The hour branch Wei (未) contains Ji, Ding and Yi: Indirect Resource, Seven Killings and Indirect Wealth. Yi consequently appears both as the visible hour stem and among that pillar’s hidden stems. Geng, by comparison, stands visibly above Wu in the year pillar.

Branch relationships occupy this lower level. Wu and Wei form a Six Combination (六合) pairing, while the two Wu branches form a self-punishment (自刑) relationship in traditional terminology. Hai and Wei also form an arching relationship toward Mao (卯). These names describe particular branch arrangements. Their participants differ from the upper Yi–Geng pair, even when the same pillars are involved.

The seasonal branch is Wu in the month pillar 壬午. Its primary hidden stem is Ding, Seven Killings relative to Xin; this supplies the Seven Killings pattern designation in this example. That month-pattern relationship compares Ding with Xin. The Yi–Geng pairing compares the year and hour stems. Each has its own participants and place in the chart, which the Ten Gods glossary helps distinguish.

Reading Yi–Geng therefore begins with a precise arrangement: Geng in the year, Yi in the hour, and Xin as the Day Master. Hidden stems and branch relationships then fill in the surrounding structure. The guide to reading a BaZi chart develops these layers together. To locate them in a personal chart, the BaZi chart calculator accepts a birth date and time and displays four pillars with Ten Gods, hidden stems, NaYin and void branches.