How Qimen Charts Are Built

One Moment, One Chart — and Only One

Ask ten tarot readers the same question and you'll watch ten different spreads hit the table. Ask ten Qimen practitioners to cast a chart for the same moment and place, using the same school, and they will produce ten identical charts, down to the last symbol. That's because nothing in the casting is left to chance or feeling. Hour-based Qimen (时家奇门), the form used for decision questions, generates exactly one chart per two-hour block: twelve charts a day, each one the deterministic result of a calculation you could do by hand with a lookup table. That determinism is one piece of why Qimen works.

The whole build is four moves. Pin down the real time. Use it to select one of eighteen base configurations, the 18 ju (十八局). Lay the ten Heavenly Stems onto the nine-palace grid. Then rotate three more layers (stars, doors, deities) into position on top. This article walks the chain end to end.

Step 1 — Fix the Time: From Your Clock to the Four Pillars

Qimen doesn't read your clock; it reads the sun. The first move is converting your wall-clock time into true solar time, correcting for your longitude and the equation of time, because "the Horse hour" means the two hours around your solar noon, not your government's. Near a two-hour boundary, this correction alone decides which chart you get.

The corrected moment is then written in the traditional calendar's language: four pillars (四柱): year, month, day, and hour, each a pair of one Heavenly Stem and one Earthly Branch. Two of these do the heavy lifting downstream: the day pillar helps select the ju, and the hour pillar drives every rotation in step four. One trap worth knowing: the Chinese day flips at 23:00, not midnight, so a question asked at 23:30 already belongs to tomorrow's day pillar.

Step 2 — Pick the Ju: Solar Terms, Yin-Yang Dun, and the Three Yuan

Now the calendar itself enters the calculation. The solar year is divided into 24 solar terms (节气), and they split at the solstices. From the Winter Solstice to the eve of the Summer Solstice, daylight is growing and yang is rising, so charts run in yang dun, and sequences are laid forward through the palaces. From the Summer Solstice back to winter, yin takes over: yin dun, and everything lays in reverse. A single fact about the moment, which half of the year it falls in, sets the direction of every arrangement that follows.

Each solar term lasts about fifteen days, and Qimen slices it into three yuan (元), upper, middle and lower, of five days each. Which yuan your day falls in is read off the day pillar: five-day groups are led by days whose stem is 甲 or 己, and the branch of that leading day assigns the group to a yuan. With the dun and the yuan known, the ju number comes straight out of a memorized table: the classical "yang dun song" and "yin dun song" that practitioners have chanted for centuries.

Nine possible yang ju plus nine possible yin ju: eighteen base configurations, and your moment selects exactly one. Different schools differ slightly in how they assign the yuan when the calendar drifts: the chai-bu method (拆补法) reads it strictly from the day pillar, while the zhi-run method (置闰法) inserts leap adjustments. But within any one school, the answer is unambiguous.

Step 3 — The Earth Plate: Hiding the General

The ju number now builds the foundation layer. The ten Heavenly Stems enter the grid, but the first of them, 甲 (Jia), never shows its face. In the old military metaphor, Jia is the supreme commander, too valuable to expose, so it hides behind its six officers, the six yi (Six Instruments): 戊, 己, 庚, 辛, 壬, 癸. This is the move the whole art is named after: Qimen Dunjia literally means "mysterious doors, hidden Jia." The remaining three stems, 乙, 丙 and 丁, are the three nobles (Three Wonders), the treasured assets the chart tracks most closely.

The laying rule is beautifully simple. The sequence above is fixed forever. The ju number tells you where 戊 starts: yang ju N starts 戊 in palace N (yang 1 starts at palace 1, yang 8 at palace 8…), and yin dun mirrors it. Then you walk the sequence through the palaces, forward through 1→2→3…→9 in yang dun, backward in yin dun, until all nine palaces hold a stem. That's the earth plate (地盘): the terrain of the moment, the fixed stage on which everything else will move.

Step 4 — Rotation: Stars, Doors, and Deities Take Their Places

Three more layers stack on top of the earth plate, and they all obey the same mechanical idea: each layer is a fixed ring of symbols that rotates as one piece. Nothing inside a ring ever reshuffles; the only question is how far the ring turns. What sets the turn is the hour pillar, specifically its xun leader (旬首), the 甲-day that opens the ten-hour cycle your hour belongs to.

The heaven plate (天盘) carries the nine stars. The star sitting over the xun leader's palace is promoted to Chief Star (Chief Star) for this chart, and the whole ring rotates until the Chief Star sits above the palace where the hour stem lives on the earth plate. The human plate (人盘) carries the eight doors: the door in the xun leader's palace becomes the Chief Door (Chief Door), and its ring rotates to the palace of the hour branch. Finally the deity plate (神盘), eight deities in fixed order, parks its own leader on the Chief Star's palace, forward in yang dun, reverse in yin.

And that's the whole machine. Four layers on a nine-palace grid: stems, stars, doors, deities, every one of them a fixed sequence rotated by a rule. This rotating-ring construction is why the method is called the rotating plate (转盘) school, and why the grid's magic-square structure matters: rotation around the Luoshu preserves its balance no matter how far any ring turns.

Why Determinism Is the Whole Point

Notice what never appeared in the chain: a dice roll, a card draw, a gut feeling. Every step was a lookup or a rotation. This is Qimen's quiet distinction among divination systems: the chart is fully reproducible. Disagreements between practitioners are disagreements of interpretation (or of school conventions decided up front), never of casting. If two charts for the same moment differ, someone made an arithmetic error, most often in the time itself: a missed solar-time correction, or a question asked at 23:30 pinned to the wrong day.

QimenIt's online Qi Men Dun Jia chart runs exactly this chain, with the error-prone parts done by machine: true solar time computed from your location, solar-term boundaries resolved to the minute, the ju read from the classical tables using the chai-bu method with rotating plates. The chart you see is the same chart a careful classical practitioner would build by hand for your moment, just built in milliseconds, every time, without the 23:00 traps. What the AI adds comes after the build: reading that finished chart against your actual question.