甲 Jia
Yang Wood, the tall straight tree. Upright, principled, and slow to bend, which is both the strength and the whole lesson.
What a Jia day master is
Yang Wood is the trunk rather than the foliage. It grows in one direction, upward, and it does not adapt its shape to the room it is in. Jia people tend to be dependable, morally legible, and quietly stubborn: you know where they stand because they have been standing there a while.
In Chinese astrology your core element is Yang Wood, pictured as the tall straight tree. You are upright and principled, you grow toward the light, and you bend rarely. That firmness is your strength, and learning when to bend is your lesson.
Jia at its best, and where it strains
Strength. Integrity that other people organise themselves around. Jia does not need to argue for its position because the position is visible.
Difficulty. A tree that cannot bend snaps in a storm. Jia struggles most where the situation requires flexibility rather than principle, and can mistake rigidity for strength right up until something breaks.
Jia shares its element with Yi, the yin form of Wood, and the two behave nothing alike. That is the whole reason BaZi uses ten stems rather than five.
The four relationships every BaZi reading runs on
Your day master is not read alone. Everything else in the chart is judged by how it treats Wood, and the five elements move in two cycles: one that nourishes and one that restrains. For a Wood day master those come out as follows.
A chart with plenty of Water and little Metal reads very differently from the reverse, even with the same day master. That balance is what a BaZi practitioner is actually looking at, and it is why two Jia people can be unrecognisable to each other.
BaZi pillars here use the solar calendar the tradition uses, so the year turns at Lichun in early February rather than at the lunar new year, and the hour pillar follows the late-Zi convention.