# The Si 巳 mountain

> A house facing 150° is in the Si 巳 mountain. Si covers every bearing from 142.5° up to 157.5°, within the Xun 巽 trigram in the Southeast, element Fire. A house facing Si sits Hai 亥 (322.5° – 337.5°) — described as sitting Hai, facing Si. To be sure, measure the facing as an exact degree.

## Facts about the Si mountain

- Name: Tỵ · Si · 巳
- Degree range: 142.5° – 157.5°
- Center: 150°
- Trigram: Xun 巽 (112.5° – 157.5°)
- Lines (bottom to top): yin, yang, yang
- Direction: Southeast
- Element of the mountain: Fire
- Element of the trigram: Wood
- Three Yuan dragon: Human Yuan dragon
- Opposite mountain (sitting): Hai 亥 · 322.5° – 337.5°
- Neighbouring mountains: Xun 巽 · Bing 丙
- Birth-year mountain: Birth-year mountain of people born in a Si (Snake) year, with years counted from the Start of Spring.

## When measuring and setting polarity

The closer a facing is to the 142.5° or 157.5° boundary, the more easily a measuring error pushes it into Xun 巽 or Bing 丙. When a reading falls within 1° of either boundary, measure again at several points before setting polarity.

Once polarity is set, every room, door or item lying within the 142.5° – 157.5° sector, seen from the center of the house, belongs to Si.

The three mountains of Xun 巽: [Chen 辰](https://myhomecheck.ai/learn/24-mountains/thin) · [Xun 巽](https://myhomecheck.ai/learn/24-mountains/ton) · [Si 巳](https://myhomecheck.ai/learn/24-mountains/ti)

## Questions about Si

### Is a house facing 150° a Southeast-facing house?

Yes, but that is not precise enough. The Southeast spans 45° (112.5° – 157.5°) and holds three mountains, Chen, Xun, Si; a house facing 150° is in Si. Naming the mountain tells apart houses only a few degrees from each other.

### What does a house facing Si sit on?

It sits Hai 亥, 322.5° – 337.5°. Sitting and facing are always exactly 180° apart.

### Whose birth-year mountain is Si?

It belongs to people born in a Si (Snake) year, counted from the Start of Spring rather than Lunar New Year. When the main door or an active, heavy item falls exactly in Si, say precisely whose Si birth-year mountain it touches.

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Original page: https://myhomecheck.ai/learn/24-mountains/ti  
Other languages: [Tiếng Việt](https://myhomecheck.ai/vi/tri-thuc/24-son/ti/index.md) · [中文](https://myhomecheck.ai/zh/learn/24-mountains/ti/index.md)  
Updated: 2026-10-21