Civil hour reference · 2021-09-09 · 09:00–11:00
September 9, 2021 · 09:00–11:00 (Si hour · Snake)
The Si hour · Snake double-hour (09:00–11:00) completes Thursday, September 9, 2021 with a fourth, hour pillar: 辛丑 · 丁酉 · 庚申 · 辛巳.
Answer first: the reference four pillars for 2021-09-09, 09:00–11:00, are year 辛丑, month 丁酉, day 庚申, hour 辛巳. The hour stem is derived from the day stem by the standard five-rat rule. This is a deterministic calendar record, not a personal reading.
Deterministic record
2021-09-09 · 09:00–11:00 at a glance
| Gregorian date | Thursday, September 9, 2021 |
|---|---|
| Double-hour | Si hour · Snake · 09:00–11:00 civil clock · branch 巳 |
| Year pillar | 辛丑 · Yin Metal Ox · Yin Metal over Earth |
| Month pillar | 丁酉 · Yin Fire Rooster · Yin Fire over Metal |
| Day pillar | 庚申 · Yang Metal Monkey · Yang Metal over Metal |
| Hour pillar | 辛巳 · Yin Metal Snake · Yin Metal over Fire |
| Hour Na Yin | 白蜡金 · hidden stems 丙 · 庚 · 戊 |
| Zi-hour convention | Early Zi: the 23:00–01:00 double-hour is anchored to this civil date at 00:00. The late-Zi school (23:00–24:00 → next day) is a documented boundary below. |
Four coordinates, four jobs
What the four reference pillars contain
Each stem-branch pair is a deterministic calendar coordinate. The hour pair inherits its branch from the double-hour and its stem from the day stem, so it stays consistent with every other hour page of this date.
Yin Metal Ox · Xin Chou
The visible stem is Xin · Yin Metal; the branch is Chou · Ox · Earth. Its Na Yin is 壁上土, and the branch contains hidden stems 己 · 癸 · 辛. Open the full Jiazi record →
Yin Fire Rooster · Ding You
The visible stem is Ding · Yin Fire; the branch is You · Rooster · Metal. Its Na Yin is 山下火, and the branch contains hidden stem 辛. Open the full Jiazi record →
Yang Metal Monkey · Geng Shen
The visible stem is Geng · Yang Metal; the branch is Shen · Monkey · Metal. Its Na Yin is 石榴木, and the branch contains hidden stems 庚 · 壬 · 戊. Open the full Jiazi record →
Yin Metal Snake · Xin Si
The visible stem is Xin · Yin Metal; the branch is Si · Snake · Fire. Its Na Yin is 白蜡金, and the branch contains hidden stems 丙 · 庚 · 戊. Open the full Jiazi record →
Calculation boundary
What this hour reference does not settle
This page uses a standard civil clock so double-hours can be compared consistently across dates. A real birth happened at a place and an instant, not inside a URL slug.
- True solar time: the reference assumes a standard-meridian civil clock. Birthplace longitude and the equation of time shift the effective hour, and can move the resolved pillar to a neighboring double-hour.
- Hour boundary: a clock time within the correction margin of an odd-hour boundary (09:00 or 11:00) is boundary-risk until resolved against place.
- Zi-hour school: the 23:00–01:00 slot follows the early-Zi convention. Late-Zi schools push 23:00–24:00 onto the next day pillar; neither this page nor the atlas settles that debate.
- Interpretation: one four-pillar record does not determine personality, career, relationships, wealth, health, or events. It is a coordinate, not a verdict.
All twelve double-hours of 2021-09-09
Resolve your actual hour pillar
Calculate the real birth chart
Add birth time and birthplace. Pillarwise resolves historical timezone, longitude correction, equation of time, and hour-boundary risk before it fixes the hour pillar — this reference page is only the civil-clock starting point.
Questions about 2021-09-09 09:00–11:00
What is the hour pillar for 09:00–11:00 on Thursday, September 9, 2021?
In this civil-clock reference, the 09:00–11:00 double-hour on 2021-09-09 carries the hour pillar 辛巳 (Yin Metal Snake), completing the four-pillar record 辛丑 · 丁酉 · 庚申 · 辛巳.
Why does the Zi hour list 23:00–01:00 as one range?
The Zi double-hour spans midnight in the classical two-segment form 23:00–01:00. This reference adopts the early-Zi convention: 00:00–01:00 belongs to the same civil date. Schools that use the late-Zi convention assign 23:00–24:00 to the next day pillar, which can change both the day and hour pillar; that difference is an open school boundary, not an error.
Is this my personal hour pillar?
Not necessarily. This page is a civil-clock reference at a standard meridian. A personal chart resolves your birthplace longitude, historical timezone, and true solar time, and any of those corrections can move the resolved hour pillar to a neighboring double-hour.
What happens near an hour boundary?
A clock time within the correction margin of an odd-hour boundary (01:00, 03:00, … 23:00) can resolve to the adjacent double-hour once longitude and equation-of-time corrections are applied. Use the calculator to see the resolved pillar and its boundary-risk flag.