A BaZi practitioner's work includes a rare but critically important procedure — 校時 (Jiao Shi, birth-hour rectification). This is working backward: instead of knowing "what time the person was born," you know "what happened to them" — and you work from those events back to the birth hour.

校時
Jiao Shi · Hour Rectification
jiào shí · "cross-checking the time"

In this article we'll cover what rectification is, when it's needed, what methods exist, in what order they're applied, and how accurate the result really is. It's a demanding technique, but understanding its principles will help you approach recovering your own birth hour with clear eyes.

1 What time rectification is

In the forward BaZi problem, we know all 4 parameters (year, month, day, hour), build the chart, and make a forecast. In the reverse problem, we know 3 parameters (year, month, day) plus a set of real life facts — and try to recover the fourth, the hour.

Since the hour branch is one of 12 possibilities, we have to choose among 12 possible charts. Every chart will be different: a different hour pillar, different hidden stems for the hour, a different Da Yun structure, a different forecast. Only one of the 12 will match the person's actual life.

The idea behind rectification: build all 12 versions of the chart and overlay them with the actual dates of key life events. Whichever version shows Da Yun and Liu Nian "working" correctly for those events is the true one.

校The principle: if BaZi is a precise system, every life should have exactly one birth hour at which all the events "line up." All the other 11 versions will produce contradictions.

2 When rectification is needed

Rectification is called for in several typical cases:

  1. The hour is entirely unknown. Soviet-era birth certificates, for example, often lacked the hour. Or the parents say, "it was morning, but I don't remember exactly."
  2. The hour is on record but doubtful. For example, "1:00 PM" with a suspicion that it's a rounded figure and the real time was different.
  3. A boundary hour. The time is recorded as "11:00 PM" or "1:00 AM" — right at the seam between two two-hour blocks. You need to decide which one it actually is.
  4. The chart doesn't match the life. The chart has been built, but the Da Yun forecasts don't hold up — the hour may be wrong.
  5. A doubtful time source. For example, the certificate says "12:30," but it's known that the maternity hospital "rounded everyone up half an hour."
  6. Immigrants and refugees. Documents are often lost, the exact time is unknown, and there's only an approximate account from the parents.

In Western astrology, rectification is a routine procedure. In BaZi it's applied less often, but in Russian practice, given the history of Soviet-era documents, it's become nearly a necessity for many clients.

3 The life-events method — the main tool

This is the core, most reliable method. Take 5-10 key life events of the client — ones that definitely happened in specific years — and check which of the 12 hour versions matches the Da Yun and Liu Nian of those events.

Which events are suitable

How the process works

  1. Take the client's birth year-month-day → build 12 chart versions with different hours.
  2. For each version, calculate the Da Yun scale (it depends on gender, the polarity of the year, and the hour).
  3. Overlay the actual event years → see which Da Yun + Liu Nian were active.
  4. Count, for each version, how many events "fire" (a logical activation).
  5. The version with the most matches is the most likely one.
The quality standard: rectification is considered reliable when the chosen version matches 70%+ of events. If it's only 50%, more data is needed, or the version is ambiguous.

4 The character method — the Day Master and the elements

This method is used as a supplement. The idea: the hour pillar shapes a person's character, but to a lesser degree than the Day Master and the month branch. Still, the hidden stems of the hour add nuance to the personality.

How the hour's element shapes character

🌳
A Wood hour (Yin, Mao)
Growth, ideals, initiative, a love of freedom, sometimes stubbornness. Later life is creative.
🔥
A Fire hour (Si, Wu)
Energy, expressiveness, a public presence, emotionality. Old age is vivid, full.
⛰
An Earth hour (Chen, Wei, Xu, Chou)
Stability, caution, persistence, care for family. Old age is settled, material.
⚔
A Metal hour (Shen, You)
Structure, discipline, an analytical mind, firm decisions. Old age carries status and authority.
💧
A Water hour (Hai, Zi)
Depth, wisdom, secretiveness, a philosophical bent. Old age is contemplative, spiritual.

If someone's character is clearly "fiery" (impulsive, passionate, a natural leader) while the Day Master is calm (say, Gui), the hour branch is likely Fire. This helps narrow the choice from 12 options down to 2-3.

5 The appearance method

In Chinese physiognomy, every Earthly Branch is linked to a type of appearance. This is an ancient method, mentioned as far back as "Drops from the Heavens," and while it doesn't give 100% accuracy, it works as an additional filter.

The correlation between branches and appearance

In reality, the hour branch only gives a shade of appearance — the main features come from the year and the day. But in borderline cases (when choosing between two neighboring hours), this method can help.

A limitation: the physiognomy method works poorly under heavy medical influence (surgery, weight loss, age-related change). It's better to use photos from ages 20-30, when the body has "settled" but hasn't yet changed much.

6 The parents method

BaZi has a clear correspondence between a person's chart and their parents' fate. Through these correspondences, you can check the hour pillar.

What's examined

Specific checks

  1. If the father died young, the chart should show damage to Indirect Wealth, or a clash between the hour and the position of Wealth.
  2. If the mother was very strong and supportive, Direct Resource should be robustly represented, and the hour pillar shouldn't be destroying it.
  3. If the parents divorced early, there should be a disconnect between Wealth and Resource in the chart, and the hour pillar plays the role of arbiter.

Example: a client says the father died when they were 7. We look at the Da Yun of that year in each of the 12 chart versions — the correct version should show a suppression of Indirect Wealth (the father). If Wealth is damaged in one version and not in the others, that version is more plausible.

7 The children method

Since the hour pillar is the Children's Palace, getting it right has a particularly strong effect on forecasts in that area.

What's checked

If a client has two children born in specific years and describes their characters, a practitioner checks each of the 12 hour versions: in which one do these facts "work"? The one that works, wins.

The method's strength: children are the most "biographically precise" information there is. Each child's birth year is fixed, and their character is known. This gives powerful calibration points.

8 The partner method

Although the partner's palace is the day, not the hour, the hour pillar still affects the marriage theme — through activation of the Spouse Star and through the chart's overall structure.

Points that get checked

The hour pillar matters especially when a person's Spouse Star is "hidden" inside the hour's hidden stems. Then the marriage activates specifically through the hour branch, and events "stick" to that part of the chart.

9 Rectification mistakes — what not to fall for

Rectification is a powerful technique, but a risky one too. Any practitioner can "fit" a chart to the facts if they don't follow strict rules. Here are the typical mistakes.

Mistake 1: Confirmation bias

The practitioner already "feels" which hour is correct, and subconsciously searches for confirmation while ignoring contradictions. The fix: keep a formal table of matches for every version, and score it.

Mistake 2: Relying on a single event

"That year was eventful, so your hour must be this one." One event proves nothing. You need at least 5-7 different events of different natures.

Mistake 3: Interpreting activations too loosely

"Well, this could be interpreted as a career event, even though the client says it was about health." If an activation doesn't match the actual nature of the event, it isn't an activation — it's a stretch.

Mistake 4: Ignoring Da Yun

Sometimes a practitioner looks only at the Liu Nian of events, but Da Yun matters more. The ten-year backdrop sets the general possibility of an event. If Da Yun contradicts it, no Liu Nian will produce that event.

Mistake 5: Over-trusting the client

The client says, "2018 was my best year." But they don't remember that the divorce actually happened in 2017, and 2018 was just the final paperwork. Verify every period carefully.

Mistake 6: Not accounting for "shadow" events

Sometimes "events" aren't a wedding or a job — they're internal processes: depression, a reevaluation of values, a spiritual crisis. These need to be included too.

⚠ The main defense against mistakes: rectification requires at least 5-10 life facts documented by year, plus a formal table of matches for each of the 12 versions. Without this rigor, the result isn't trustworthy.

10 Rectification accuracy vs. verification

The central question: how accurate is rectification? Can life events recover the hour down to the minute?

Realistic accuracy

  1. Accuracy to within 2 hours (one BaZi double-hour) — this is a reliable goal for rectification. For example, "you were born in the Si hour (9-11) or the Wu hour (11-13)" — after rectification we can confidently say which one.
  2. Accuracy to within 1 hour — possible if rectification yields strictly one version and there's a boundary case. But less often reliable.
  3. Accuracy to within 30 minutes — excessive for BaZi, because the system works in double-hours. Within one double-hour, the chart is identical.
  4. Accuracy to the minute — impossible in BaZi by definition. That's a level of precision from Western astrology (where a minute changes the ascendant), but BaZi doesn't have that.

So the goal of rectification in BaZi is to determine the correct birth double-hour. That's enough to build a complete chart.

Verification after rectification

Once we've chosen an hour version, we need verification — testing the chart's performance against new data. For example:

  1. Forecast forward 2-3 years. What should happen according to the chart? Write it down.
  2. A year later, check against the facts. If 70%+ of the forecasts came true, the chart is working, and the rectification is correct.
  3. If much of it didn't come true, the rectification may be off. Return to the process.

This cycle — "rectify → verify → correct" — is the gold standard. A good practitioner doesn't stop at the first "good guess," but pushes the chart to a level where it reliably forecasts.

Rectification is a dialogue with destiny. First you question it through the life lived; then you confirm it through the future.

Comparing the methods

In real practice, a practitioner combines all the methods, using the events method as the foundation and the rest as filters for resolving contradictions.

We don't offer rectification

We don't perform or sell birth-hour selection based on life events: this method isn't offered. A separate page explains where to actually find your exact birth time, and what a chart looks like without an hour — a three-pillar chart is built for free.

What to do if your hour is unknown →

Rectification isn't "guessing" or "intuition." It's a careful, mathematical procedure based on the correlation between a chart's structure and life's facts. Done properly, the result is reliable. Done carelessly, it's better to work with three pillars than with a "false hour."

In classical practice, rectification is a small detective story, one in which the fine fabric of the birth time is reconstructed through the events of a life. And every time, it's striking how precisely a chart "responds" to the right hour: suddenly everything falls into place, the past makes sense, and the future becomes clearer.