Civil hour reference · 2023-04-21 · 03:00–05:00
April 21, 2023 · 03:00–05:00 (Yin hour · Tiger)
The Yin hour · Tiger double-hour (03:00–05:00) completes Friday, April 21, 2023 with a fourth, hour pillar: 癸卯 · 丙辰 · 己酉 · 丙寅.
Answer first: the reference four pillars for 2023-04-21, 03:00–05:00, are year 癸卯, month 丙辰, day 己酉, hour 丙寅. 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
2023-04-21 · 03:00–05:00 at a glance
| Gregorian date | Friday, April 21, 2023 |
|---|---|
| Double-hour | Yin hour · Tiger · 03:00–05:00 civil clock · branch 寅 |
| Year pillar | 癸卯 · Yin Water Rabbit · Yin Water over Wood |
| Month pillar | 丙辰 · Yang Fire Dragon · Yang Fire over Earth |
| Day pillar | 己酉 · Yin Earth Rooster · Yin Earth over Metal |
| Hour pillar | 丙寅 · Yang Fire Tiger · Yang Fire over Wood |
| Hour Na Yin | 炉中火 · hidden stems 甲 · 丙 · 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 Water Rabbit · Gui Mao
The visible stem is Gui · Yin Water; the branch is Mao · Rabbit · Wood. Its Na Yin is 金箔金, and the branch contains hidden stem 乙. Open the full Jiazi record →
Yang Fire Dragon · Bing Chen
The visible stem is Bing · Yang Fire; the branch is Chen · Dragon · Earth. Its Na Yin is 沙中土, and the branch contains hidden stems 戊 · 乙 · 癸. Open the full Jiazi record →
Yin Earth Rooster · Ji You
The visible stem is Ji · Yin Earth; the branch is You · Rooster · Metal. Its Na Yin is 大驿土, and the branch contains hidden stem 辛. Open the full Jiazi record →
Yang Fire Tiger · Bing Yin
The visible stem is Bing · Yang Fire; the branch is Yin · Tiger · Wood. Its Na Yin is 炉中火, and the branch contains hidden stems 甲 · 丙 · 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 (03:00 or 05:00) 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 2023-04-21
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 2023-04-21 03:00–05:00
What is the hour pillar for 03:00–05:00 on Friday, April 21, 2023?
In this civil-clock reference, the 03:00–05:00 double-hour on 2023-04-21 carries the hour pillar 丙寅 (Yang Fire Tiger), completing the four-pillar record 癸卯 · 丙辰 · 己酉 · 丙寅.
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.