What is San He?
San He (三合), or "Three Harmonies," is the foundational geometric principle underlying Zi Wei Dou Shu chart interpretation. It defines which palaces resonate with each other and form unified reading groups.
The Geometry
The 12 palaces are arranged in a circle. San He connects every fourth palace, forming equilateral triangles:
子 (Zi)
亥 丑
戌 寅
酉 卯
申 辰
未 (Wei)
午 (Wu)
巳 (Si)
Triangle 1: 子-辰-申 (Water)
Triangle 2: 丑-巳-酉 (Metal)
Triangle 3: 寅-午-戌 (Fire)
Triangle 4: 卯-未-亥 (Wood)
Why It Matters
When you read a palace, you don't read it alone — you read its entire San He triangle. The stars in the two connected palaces directly influence the palace you're examining.
Example: Reading the Self Palace
If the Self Palace (命宫) is in Zi (子), its San He partners are:
- Chen (辰) → Career Palace (官禄宫)
- Shen (申) → Wealth Palace (财帛宫)
All stars in Career and Wealth contribute to the Self Palace reading. A practitioner who only reads the Self Palace's own stars is missing two-thirds of the picture.
The "Opposite Palace" (对宫)
In addition to the San He triangle, each palace's direct opposite also influences it. Combined, this gives every palace four sources of influence:
- The palace itself (本宫)
- San He partner 1 (三合)
- San He partner 2 (三合)
- Opposite palace (对宫)
This four-palace reading group is called the Si Zheng (四正) system.
Practical Application
Step-by-step palace reading:
- Identify the target palace and its San He + opposite partners
- List all major and auxiliary stars across all four palaces
- Weight stars: stars in the target palace carry full weight; triangle partners carry ~70%; opposite palace carries ~50%
- Check transformers across all four positions — a Hua Ji in a triangle partner still affects the target
- Synthesize the combined reading
Common Mistakes
- Reading palaces in isolation (ignoring San He influence)
- Treating triangle partners as equally weighted (they're influential but secondary)
- Forgetting that the opposite palace provides contrast, not just supplementary energy — it represents what the native projects outward vs. holds within