Prenatal and Postnatal Signals
Last updated 5/21/2026
Plum Blossom becomes easier when you know what kind of signal you are using.
Some inputs are fixed. Some arrive suddenly. The method can use both, but they do not feel the same.
Two Signal Families
| Signal family | What it uses | Reading tone |
|---|---|---|
| Prenatal | fixed or inherited data: date, birth data, formal calendar values, stable numbers | pattern already present before the question |
| Postnatal | events arising in the moment: sound, direction, movement, color, count, interruption | pattern appearing through the present environment |
Do not treat these labels as rigid dogma. Use them as a practical teaching distinction.
A prenatal input asks, โWhat pattern is already encoded in the time or data?โ
A postnatal input asks, โWhat did the moment just show?โ
Why This Matters
The mistake is mixing signal types without noticing.
If you ask a horary question using lunar month, lunar day, and hour branch, you are doing a calendar-style reading. If three knocks happen while the question is spoken, you are doing an event-style reading. If you combine them, say exactly how and why.
The student should always be able to answer:
- Was my input fixed data or a spontaneous event?
- Did the cue exist before the question, or did it appear during the question?
- Did I choose the rule before seeing the hexagram?
- Could someone else reproduce my calculation from my notes?
Examples
| Situation | Signal family | Good use |
|---|---|---|
| A question is asked at Shen hour on the twenty-first lunar day | Prenatal / calendar | Use a stated horary formula. |
| A glass breaks as the question is spoken | Postnatal / event | Count or classify the event before interpreting. |
| A client gives a room number that has been bothering them | Prenatal-like fixed number | Use direct-number method if the number belongs to the question. |
| A bird calls five times from the east | Postnatal / observed cue | Use count, direction, or both with a declared rule. |
| You open a book at random and use the page number | Postnatal / selected count | Treat the action as the casting event. |
The Rule of Significance
Postnatal readings need restraint.
Use a cue when there is new change, new movement, or a new event. A signal should arrive, interrupt, shift, appear, sound, fall, open, close, or otherwise become distinct.
Do not turn background conditions into omens after the fact. If the lamp was already on, the lamp is not automatically the signal. If it flickers at the moment of the question, it may be.
Course Case
The workshop proposal case uses a postnatal cue:
As the question is asked, three messages arrive in a group chat and the wall clock reads 14:27.
The three messages are the new event. The visible clock supports the event by giving a number in the same moment. The reading is not a formal calendar horary reading because we are not converting lunar month, lunar day, or hour branch.
That distinction keeps the method honest.
Practice
For one day, keep an observerโs log without casting.
Record three possible signals:
- What happened.
- Whether it was fixed data or a new event.
- Why it drew attention.
- How it could become a number, direction, trigram, or moving line.
- Whether you would actually use it, or leave it alone.
This trains the most important skill in Plum Blossom: noticing without grabbing.
Next, learn the number grammar. Continue to The Language of Numbers.