Structure Tables
Every two-hour period in hour Qimen belongs to a "structure". After the Winter Solstice yang grows, so the twelve terms from Winter Solstice to Grain in Ear use the yang escape; after the Summer Solstice yin grows, so Summer Solstice to Major Snow use the yin escape. Each term of about fifteen days is split into upper, middle and lower periods of five days, each with its own structure number.
| Solar term | Escape | Upper | Middle | Lower |
|---|---|---|---|---|
| Winter Solstice 冬至 | Yang | 1 | 7 | 4 |
| Minor Cold 小寒 | Yang | 2 | 8 | 5 |
| Major Cold 大寒 | Yang | 3 | 9 | 6 |
| Start of Spring 立春 | Yang | 8 | 5 | 2 |
| Rain Water 雨水 | Yang | 9 | 6 | 3 |
| Awakening of Insects 驚蟄 | Yang | 1 | 7 | 4 |
| Spring Equinox 春分 | Yang | 3 | 9 | 6 |
| Clear and Bright 清明 | Yang | 4 | 1 | 7 |
| Grain Rain 穀雨 | Yang | 5 | 2 | 8 |
| Start of Summer 立夏 | Yang | 4 | 1 | 7 |
| Grain Buds 小滿 | Yang | 5 | 2 | 8 |
| Grain in Ear 芒種 | Yang | 6 | 3 | 9 |
| Summer Solstice 夏至 | Yin | 9 | 3 | 6 |
| Minor Heat 小暑 | Yin | 8 | 2 | 5 |
| Major Heat 大暑 | Yin | 7 | 1 | 4 |
| Start of Autumn 立秋 | Yin | 2 | 5 | 8 |
| End of Heat 處暑 | Yin | 1 | 4 | 7 |
| White Dew 白露 | Yin | 9 | 3 | 6 |
| Autumn Equinox 秋分 | Yin | 7 | 1 | 4 |
| Cold Dew 寒露 | Yin | 6 | 9 | 3 |
| Frost Descent 霜降 | Yin | 5 | 8 | 2 |
| Start of Winter 立冬 | Yin | 6 | 9 | 3 |
| Minor Snow 小雪 | Yin | 5 | 8 | 2 |
| Major Snow 大雪 | Yin | 4 | 7 | 1 |
Finding the period: the period head
The period comes from the "period head" of the day pillar: the most recent Jia or Ji day (the day itself if it is one). If its branch is Zi, Wu, Mao or You, it is the upper period; Yin, Shen, Si or Hai, the middle; Chen, Xu, Chou or Wei, the lower. The head changes every five days, so three periods make fifteen days.
Chai Bu and Zhi Run
Solar terms and period heads do not always line up, and there are two main ways to handle this:
- Chai Bu
- Use the term the moment actually falls in and the period head of that day. Simple and consistent, it is the method most modern software uses, and the one this site uses.
- Zhi Run
- Aligns period heads with terms, calling early arrivals "surpassing" and late ones "connecting", and repeats a term at Grain in Ear or Major Snow when the gap grows too large. Schools differ in the details.
A new day starts at 23:00 with the Zi hour. Within a few minutes of a term change, different software may disagree by one structure because of differences in term timing.
This is fixed text compiled from general convention, not a reading of any individual and not a prediction. For important decisions, please consult qualified professionals.