Why Your Birth Time Matters: The Hour Pillar

The Fourth Pillar

In a complete Saju reading, you have four pillars: Year, Month, Day, and Hour. While you can calculate three pillars from just your birth date, the Hour Pillar requires knowing when you were born—ideally within a two-hour window.

Many people don’t know their exact birth time, which raises important questions: How crucial is it? What are you missing without it? Can you still get value from Saju?

What the Hour Pillar Reveals

Inner World and Hidden Self

The Hour Pillar (시주/時柱) represents aspects of your personality that may not be immediately visible:

Your private thoughts and inner motivations
How you behave when completely comfortable
Subconscious patterns and instincts
Your relationship with your own potential

While the Day Pillar shows your core identity (how you fundamentally are), the Hour Pillar shows what lies beneath that—your inner landscape.

Children and Legacy

Traditionally, the Hour Pillar is associated with:

Relationship with children
What you leave behind
Later life (approximately ages 45+)
Long-term goals and aspirations

Completing the Picture

Without the Hour Pillar, you’re missing:

2 out of 8 characters in your full chart
Important element balance information
Interactions between the Hour and other pillars
A full understanding of your inner dynamics

The Twelve Two-Hour Periods

Saju divides the day into twelve two-hour periods, each governed by an Earthly Branch:

Period	Branch	Animal	Hours
1	子 (Ja)	Rat	23:00-01:00
2	丑 (Chuk)	Ox	01:00-03:00
3	寅 (In)	Tiger	03:00-05:00
4	卯 (Myo)	Rabbit	05:00-07:00
5	辰 (Jin)	Dragon	07:00-09:00
6	巳 (Sa)	Snake	09:00-11:00
7	午 (O)	Horse	11:00-13:00
8	未 (Mi)	Goat	13:00-15:00
9	申 (Sin)	Monkey	15:00-17:00
10	酉 (Yu)	Rooster	17:00-19:00
11	戌 (Sul)	Dog	19:00-21:00
12	亥 (Hae)	Pig	21:00-23:00

The Special Case of Midnight

The Rat hour (子時) spans midnight, running from 23:00 of one day to 01:00 of the next. This creates a traditional debate:

Zi Shi (子時) split: Some practitioners split this period at midnight
Traditional view: Others treat it as one continuous period

This mainly matters if you were born very close to midnight.

How to Find Your Birth Time

Official Records

In many countries, birth time is recorded on:

Birth certificates
Hospital records
Health records

In Korea, birth time has traditionally been important, so older birth records often include it.

Family Memory

Ask family members, particularly:

Your mother (most likely to remember)
Other relatives who were present
Check baby books or journals

Even approximate times (“early morning,” “around dinner time”) can narrow it to a two-hour window.

Hospital Records

If you were born in a hospital, they may have more detailed records than what appears on your birth certificate. It’s worth requesting complete birth records.

What If You Don’t Know Your Birth Time?

Working with Three Pillars

A three-pillar reading still provides significant insight:

Year Pillar: Social persona, family background
Month Pillar: Career, early adulthood
Day Pillar: Core identity, marriage

The Day Pillar alone—particularly your Day Master—offers substantial information about your fundamental nature.

Rectification

Some advanced practitioners offer “rectification”—attempting to determine birth time by:

Analyzing known life events
Comparing personality to different hour possibilities
Using other timing techniques

This is speculative and should be approached carefully.

Accept the Unknown

There’s value in accepting what we don’t know. A three-pillar reading is still meaningful, and forcing an uncertain Hour Pillar might introduce inaccuracies.

Timezone Considerations

Historical Time Zones

Birth time should be converted to the local time that was in use when and where you were born. This can be complicated by:

Daylight Saving Time: Was DST in effect?
Historical timezone changes: Some regions have changed time zones
War time: Some countries used different times during wartime

Korea Specifically

Korea has used different timezones historically:

Before 1908: Local solar time
1908-1954: Various changes
Since 1954: KST (UTC+9), with brief exceptions

If you were born in Korea before 1954, timezone research may be needed.

Converting to True Solar Time

Some traditional practitioners convert to “true solar time” based on longitude. Most modern calculators use standard timezone time, which is generally acceptable for self-reflection purposes.

Hour Pillar and Other Pillars

Harmony and Conflict

The Hour Branch can form harmonies or conflicts with other branches in your chart:

Harmony with Day Branch: Internal peace and integration
Conflict with Day Branch: Inner tension, complex personality
Year-Hour relationships: How your inner self relates to your social expression

Element Balance Impact

Two more elements from the Hour Pillar affect your overall balance. For example:

If you lack Water in your three pillars, an Hour Pillar containing Water would change the picture
Strong element patterns are affected by Hour Pillar additions

Practical Advice

For Complete Readings

If you know your birth time:

Convert to the timezone used at your birthplace
Account for any Daylight Saving Time
Use a reliable calculator that handles timezones

For Unknown Birth Times

If you don’t know:

Calculate your three-pillar chart
Read interpretations for Day Master (still very relevant)
Consider the Hour Pillar as “unknown” rather than guessing
Accept that some aspects are mysteries

Don’t Obsess

Remember: Saju is for self-reflection, not prediction. A complete chart is nice to have, but your life isn’t determined by whether you know your birth hour. Many people find profound value in three-pillar readings.

Calculate Your Chart

Ready to see your pillars? Use our Saju Calculator. If you know your birth time, enter it; if not, leave it blank and the calculator will generate your three visible pillars.