Heavenly Stems

What it is

The ten heavenly stems (天干, cheon-gan) are the top half of every pillar in a Four Pillars chart — each pillar pairs one stem with one earthly branch. There are exactly ten: 甲 (gap), 乙 (eul), 丙 (byeong), 丁 (jeong), 戊 (mu), 己 (gi), 庚 (gyeong), 辛 (sin), 壬 (im), 癸 (gye). They cycle in that fixed order and repeat every ten years, which is why the year stem alone is not enough to identify a birth year — it takes the full 60-term stem-branch cycle to do that.

Each stem carries exactly one of the five elements in one of two polarities: 甲/乙 are wood (yang/yin), 丙/丁 are fire, 戊/己 are earth, 庚/辛 are metal, 壬/癸 are water. The polarity matters for how two stems relate to each other — same polarity produces one kind of ten-god relationship, opposite polarity produces another.

Worked example

The stem 丁 (jeong) is fire in its yin form. Compared against another fire stem, 丙 (byeong, yang fire), the two are the same element but opposite polarity — that pairing is read as a "劫財" (competing peer) relationship rather than a "比肩" (matching peer) one, purely because of the polarity difference, not the element.

How Mystica computes it

Every pillar in the free Saju reading carries a real stem drawn from this table of ten, computed from the lunar calendar conversion of your birth date — never a placeholder or a simplified 5-element-only chart that drops the yin/yang distinction.