What Is the Sexagenary Cycle (60 Jiazi)? Why Heavenly Stems + Earthly Branches Make Only 60 Pairs

TL;DR (Read in 30 Seconds)

1. What Exactly Is “60 Jiazi”?

If you’re learning Bazi (Four Pillars), the first step is recognizing stems/branches. The next common “wall” is understanding 60 Jiazi.

From an information-system perspective, 60 Jiazi is simply a standardized indexing system:

So you can think of it like this:

• Year Pillar = one Jiazi pair
• Month Pillar = one Jiazi pair
• Day Pillar = one Jiazi pair
• Hour Pillar = one Jiazi pair

Together, these four pairs make up your Bazi chart.

2. There Are 10 Stems and 12 Branches — Why Isn’t It 120?

A very common beginner question:

• 10 Heavenly Stems: Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui
• 12 Earthly Branches: Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai

It’s natural to think “10 × 12 = 120”. But the charting system uses only 60 because of a strict pairing rule.

The key rule: Yang stem with Yang branch; Yin stem with Yin branch

Both stems and branches have Yin/Yang polarity.

• Yang stems: Jia, Bing, Wu, Geng, Ren
• Yin stems: Yi, Ding, Ji, Xin, Gui
• Yang branches: Zi, Yin, Chen, Wu, Shen, Xu
• Yin branches: Chou, Mao, Si, Wei, You, Hai

The pairing rule is:

• Yang stem can only pair with a Yang branch
• Yin stem can only pair with a Yin branch

That implies:

• Each stem only pairs with 6 out of the 12 branches
• Total valid pairs become 60

(You may see deeper topics like “Empty Branch/Empty Void (空亡)” mentioned in relation to the 60 Jiazi table. For beginners, it’s better to master the cycle logic first.)

3. How the 60 Jiazi Table Is Generated (Order + Rotation)

You don’t need to memorize the whole table upfront if you understand the generation logic:

1. Stems cycle in order:
   Jia → Yi → Bing → Ding → Wu → Ji → Geng → Xin → Ren → Gui

2. Branches cycle in order:
   Zi → Chou → Yin → Mao → Chen → Si → Wu → Wei → Shen → You → Xu → Hai

3. Start from Jia-Zi and advance both sequences while maintaining Yin/Yang matching. You get:

• #1: Jia-Zi
• #2: Yi-Chou
• #3: Bing-Yin
• …
• #60: Gui-Hai

After #60, it loops back to #1.

4. Why Is It Called “Jia-Zi”? Why Does 60 Years = “One Jiazi”?

The cycle begins with Jia-Zi, so “Jiazi” is often used as shorthand for the entire 60-unit loop.

That’s why you may hear:

• 60 years = one Jiazi cycle
• Age 60 is sometimes referred to as Hua Jia (花甲) in traditional expressions

This is simply a linguistic reflection of the time-keeping system.

5. How 60 Jiazi Connects to Bazi Charting (Practical Use)

When you cast a Bazi chart, you get four pillars (year/month/day/hour). Each pillar is written as:

• one stem
• one branch

So effectively:

• each pillar is one unit from the 60 Jiazi cycle

A high-leverage beginner exercise (3 minutes/day)

1. Cast your own Four Pillars
2. Identify each pillar as one Jiazi pair
3. Don’t chase advanced conclusions yet — just become fluent with the “units”

This will make later learning (Five-Element relationships, Ten Gods, etc.) much easier.

6. Common Beginner Mistakes

1. Treating 60 Jiazi as pure rote memorization: learn the pairing logic first.
2. Reciting sequences without understanding: knowing “Jia-Zi, Yi-Chou…” is less useful if you can’t explain why.
3. Jumping ahead to advanced topics too early: weak foundations make everything feel confusing later.

FAQ

Do I need to memorize all 60 pairs?

Not at the start. But you should be able to:

• recognize that a pair like Jia-Zi / Geng-Shen / Gui-Hai is a valid Stem-Branch unit
• explain clearly why there are 60, not 120

Does 60 Jiazi apply to days and hours too?

Yes. The Ganzhi system can label year/month/day/hour, and each unit cycles through the 60 pairs.

What is “Empty Void (空亡)”? Should I learn it now?

It is related to sub-structures inside the 60 Jiazi cycle, but it’s more advanced.

A recommended order is:

• stems & branches → 60 Jiazi → Five Elements generating/controlling → Ten Gods
• then: Empty Void / Shen Sha (auxiliary stars), etc.

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Next, we’ll cover the Five-Element generating/controlling cycle with a beginner-friendly mnemonic and practical intuition.