Chart Correction
Should You Use True Solar Time?
True solar time does not make a chart more mystical. It converts civil clock time back to the sun's local position. It only changes the Hour Pillar when the birthplace is far from 120°E and the clock sits near a two-hour boundary.
TianJiGe Editorial TeamUpdated
Turn it on if you know the birth city. If the hour sits well inside a two-hour branch, or the place is near 120°E, both settings often produce the same chart. If you do not know the birthplace, keep clock time—do not pick a random city to 'correct' it.
Clock time and solar time are not the same clock
Most civil birth times in China follow Beijing Time, standardized to 120°E (near Hangzhou and Shanghai). However, local solar time follows the sun's physical passage across the sky: every 1 degree of longitude equals roughly 4 minutes of time difference.
Real-world comparison: Urumqi (approx. 87°36′E) is about 130 minutes (2h 10m) behind Beijing Time; Chengdu (approx. 104°04′E) is about 64 minutes behind; Xi'an (approx. 108°56′E) is about 44 minutes behind; while Shanghai (approx. 121°28′E) is only 6 minutes ahead.
Traditional Four Pillars (Ba Zi) calculates the Hour Pillar from true local solar hours, not civil administrative time zones. True solar time correction adjusts standard clock time back to local sundial time before assigning the two-hour earthly branch.
When it must be on, and when it changes nothing
Earthly branches change every two hours. True solar time correction changes your Ba Zi chart only when the adjusted time crosses a branch boundary.
【Case 1 - Hour Pillar Changes】: Born in Chengdu at 09:15 clock time (nominally inside the 09:00–11:00 Chen hour). Subtracting 64 minutes brings local solar time to 08:11, sliding into the 【Mao hour 07:00–09:00】. The Hour Pillar changes completely from Chen to Mao.
【Case 2 - Chart Stays Identical】: Born in Shanghai or Hangzhou at 10:00 clock time. A minor shift of a few minutes keeps the birth comfortably inside the 【Chen hour】, leaving all Four Pillars completely unchanged.
【Case 3 - Day Boundary Shift】: Born in Xi'an at 23:20 clock time (nominally the next day's Zi hour). Subtracting 44 minutes brings local time back to 22:36, which is 【Hai hour of the current day】. Here both the Hour Pillar and the Day Pillar shift back by one day.
Do not force it without a birthplace
True solar time strictly depends on exact city longitude. Selecting an arbitrary city without knowing the real birthplace risks applying correction in the wrong direction and breaking a pillar that was previously accurate.
If only the province is known, generate a reference chart using clock time first, then compare with the provincial capital. If the hour branch changes, mark the chart with 'Hour Pillar Pending Verification'.
When the birthplace is completely unknown, disable solar time correction and stick with civil clock time. Stacking an inaccurate longitude on top of an approximate birth time adds error rather than precision.
What to check after turning it on
If the earthly branch of the Hour Pillar does not change after correction, the Day Master strength, Five Elements balance, Ten Gods structure, and Major Luck Pillars (Da Yun) remain 100% identical.
If the Hour Pillar changes, review the specific Ten Gods and palace attributes associated with the hour branch. The Hour Pillar reflects later life, children, personal aspirations, and subconscious output, while Year and Month pillars remain untouched.
For births near 23:00 (the boundary between Hai and Zi hours), always verify whether the Day Pillar has crossed the day boundary along with the hour.
How to Get Started
- 1Confirm the civil clock time from hospital records or family notes.
- 2Enable true solar time only when an exact birth city is known.
- 3Check whether the Hour Pillar branch changed after correction.
- 4If unchanged, proceed with the original chart; if changed, update late-life and output readings.
- 5Near 23:00, check the Day Pillar alongside the hour branch.
- 6Without a birthplace, keep clock time and note the Hour Pillar as pending.
Common Mistakes
- Picking a random city because you do not know the real birthplace.
- Assuming the chart is inaccurate unless true solar time is enabled.
- Focusing only on longitude difference while ignoring proximity to two-hour branch boundaries.
- Retaining old interpretations after the Hour Pillar has changed.
- Treating true solar time as a tool to engineer a 'luckier' chart.
Try the Tool
Ba Zi — Four Pillars
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FAQ
No. It is most impactful with a known birthplace near odd-hour boundaries (1, 3, 5, 7, 9, 11 o'clock or 23:00). Charts in eastern coastal regions or mid-branch times often remain identical.
Year, month, and day pillars are unaffected. The only difference is the Hour Pillar, and only when longitude offset crosses a branch division.
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