BaZi Concepts
What Are Tai Yuan and Tai Xi in BaZi?
Also called: Tai Yuan Yu Tai Xi, Tai Yuan, Tai Xi
Plain Explanation
Tai Yuan and Tai Xi are two traditional auxiliary chart labels, each expressed as a Stem–Branch pair. In ChiBuddy’s method, Tai Yuan is derived from the Month Pillar and Tai Xi from the Day Pillar. They are separate labels and do not change the birth Four Pillars.
First distinguish the Month Pillar from the Day Pillar in an already calculated chart. The examples derive auxiliary pairs from them; they do not add another birth pillar.
Example
In ChiBuddy, Tai Yuan is obtained by advancing the Month Stem by one position and the Month Branch by three, cycling through each sequence. For a Ji–Si (己–巳) Month Pillar, the next Stem after Ji is Geng (庚), and the third Branch after Si is Shen (申), giving Geng–Shen (庚–申). A Ren–Wu (壬–午) month similarly gives Gui–You (癸–酉).
| Source Month Pillar | Tai Yuan |
|---|---|
| Ji–Si (己–巳) | Geng–Shen (庚–申) |
| Ren–Wu (壬–午) | Gui–You (癸–酉) |
This illustrates Tai Yuan derived from a given Month Pillar. It is neither a complete chart nor a record of an actual conception date.
Tai Xi calculation examples
| Source Day Pillar | Tai Xi |
|---|---|
| Jia–Zi (甲–子) | Ji–Chou (己–丑) |
| Yi–Chou (乙–丑) | Geng–Zi (庚–子) |
Tai Xi uses the Day Stem’s Five Combination partner and the Day Branch’s Six Combination partner. A Jia–Zi (甲–子) day gives Ji (己) from Jia and Chou (丑) from Zi, forming Ji–Chou (己–丑). This does not establish that combination or transformation has occurred in the chart.
How to Check
- 1
Use the Month Pillar for Tai Yuan and the Day Pillar for Tai Xi
The two labels use different starting points. Identify the Month and Day Pillars already calculated by ChiBuddy, then apply the corresponding rule. Their results cannot be interchanged.
- 2
Look up Nayin separately for each resulting pair
Each result is still a Stem–Branch pair with its own Nayin. Nayin is a separate classification of the whole pair. The Nayin of Tai Yuan or Tai Xi must not be treated as the Day Master’s element.
What It Is Used For
Understanding Tai Yuan and Tai Xi helps you identify where additional chart fields come from, without confusing them with the Month Pillar, Day Pillar, or Nayin. When comparing results from different chart calculations, first check the calculation methods and which auxiliary label is being compared.
Common Misunderstandings
Is the current method the only method found in traditional texts?
Ming Li Ji Cheng records both the method that advances the Month Stem by one position and the Month Branch by three, and San Ming Tong Hui’s account using three hundred days before birth. These are different approaches. ChiBuddy’s Month Pillar method is not the single method used in every traditional text.
Do the names reveal the actual time of conception?
These are auxiliary labels in traditional metaphysical practice. Deriving a Stem–Branch pair from the birth Month or Day Pillar does not identify an actual conception date or establish a reproductive outcome.
Can these auxiliary labels replace the birth Four Pillars?
The birth Four Pillars still record the birth year, month, day, and hour. Tai Yuan and Tai Xi are additional labels that cannot replace any of those pillars. One auxiliary result alone cannot provide a complete analysis of the chart.
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Updated 2026-10-16 · Editorial Policy