Which School of Qi Men Dun Jia Does Qimena Use? Chai-Bu and Zhuan-Pan Explained

Why do two tools give different charts for the same moment?

Anyone who compares Qi Men Dun Jia tools runs into this sooner or later: the same birth moment, run through a different tool, produces a different chart — the Three Nobles and Six Yi land in different palaces, sometimes even the Yin/Yang Ju number itself disagrees.

Usually neither tool is simply wrong. They are following different rules, because across centuries of Qi Men literature, two specific steps have never had a single universally agreed method:

How the Three Yuan periods are fixed — the Chai-Bu method vs. the Zhi-Run (leap-insertion) method
How the Nine Stars and Eight Gates are arranged — the Zhuan-Pan (rotating-disk) method vs. the Fei-Pan (flying-star) method

These two choices materially change the chart. Qimena’s engine explicitly uses Chai-Bu to fix the Ju, and Zhuan-Pan to lay out the plates. Here is what that means and why it was chosen.

Fixing the Ju: the Chai-Bu method

Before anything else, a Qi Men chart needs a “Ju number,” determined jointly by the current solar term and the Three Yuan period. Classical texts split on how the Three Yuan boundary is fixed:

Chai-Bu (“dismantle and patch”): each solar term is treated as a closed interval — its own Three Yuan arrangement applies for the whole term and is never mixed with the arrangement of another term. The specific Yuan (Upper, Middle or Lower) is read directly off the branch of the day’s Fu Tou (the leading 甲/Jia or 己/Ji day of its ten-day cycle): Zi/Wu/Mao/You branches mean Upper Yuan, Yin/Shen/Si/Hai mean Middle Yuan, Chen/Xu/Chou/Wei mean Lower Yuan.
Zhi-Run (“leap insertion”): when the Fu Tou cycle drifts out of step with the solar-term cycle, a Yuan’s arrangement is deliberately repeated to catch the two cycles back up.

Qimena uses Chai-Bu: solar terms come from a real-time astronomical calculation of the sun’s ecliptic longitude (not a lookup table), and the Yuan is read directly from the Fu Tou branch with no manual catch-up judgment involved. The direct benefit is determinism — feed in the same moment and you get the same Ju number every time, regardless of who runs it or when, with no room for one practitioner’s opinion on “does this need a leap insertion” to change the outcome. This is the concrete, method-level expression of something Qimena says a lot: the chart is computed, not generated.

Laying out the plates: the Zhuan-Pan method

Once the Ju number is fixed, the Three Nobles, Six Yi, Nine Stars, Eight Gates and Eight Deities still need to be placed into the Nine Palaces. This step also has two mainstream approaches:

Zhuan-Pan (“rotating disk”): the Nine Stars, Eight Gates and Eight Deities each keep their original relative order and rotate together, as one block, around the eight outer palaces to their new positions. The centre palace is never used directly — it borrows from another palace.
Fei-Pan (“flying”): relative order is discarded; each element is re-placed independently following the fixed 1-through-9 sequence of the Luo Shu. The centre palace can be used directly, with no borrowing required.

Qimena uses Zhuan-Pan, for the same reason as its choice above: under Zhuan-Pan, the Nine Stars, Eight Gates and Eight Deities move as a coherent unit, so pattern detection — configurations like Fu Yin (self-repeating) or Fan Yin (reversal) — evaluates that unit’s state as a whole. This matches how most Hour-based Qi Men texts describe the system, and it is the more widely practiced arrangement.

What the two choices add up to

Chai-Bu removes ambiguity from “when is this chart cast” — the same moment always yields the same Ju. Zhuan-Pan removes ambiguity from what happens next — the stars, gates and deities move as one block, with no per-element judgment call about where any single piece flies. Together, this means that once the time and place are fixed, Qimena’s chart is uniquely determined and independently reproducible — it will not change because the chart was recast later, or by a different person, or on a different tool run.

This matters more than usual outside China. Qimena adds one more layer on top of this system: True Solar Time correction, converting clock time to the solar time a chart actually needs based on the user’s real longitude and current DST status. That correction is not a school’s proprietary technique — it is a modern computational step that any system needs when practiced overseas. Most classical texts assume the practitioner is in China and never address timezones, daylight saving, or western longitudes; a tool has to add this layer itself, or the hour used for casting is simply wrong before any question of method even applies.

Check it yourself

If you want to verify a specific chart, you can work through the same method by hand: find the solar term and Fu Tou for the moment in question, use Chai-Bu to fix the Yuan and Ju number, then use Zhuan-Pan to place the Nine Stars and Eight Gates into the Nine Palaces. Qimena’s charting engine runs this exact deterministic process every time — the same moment and place will always produce the same chart, no matter when you regenerate it.