Should Bazi Use Beijing Time?
Learn when China Standard Time is the correct civil input for Bazi, why overseas births use local historical time, and how longitude remains separate.
Overview
Use Beijing Time only when it was the applicable civil clock for the birth location and historical date, or when the source record is explicitly stated in that time standard. Modern China Standard Time is UTC+8 and its standard meridian is 120°E; it is not a universal clock for every Bazi birth. Overseas records should first use their local historical zones. Even within one UTC+8 zone, a selected true-solar-time method can still apply birthplace longitude.
At a glance
- Modern standard
- China Standard Time, UTC+8
- Standard meridian
- 120 degrees east
- Correct use
- Applicable local civil rule or explicitly recorded standard
- Not universal
- Overseas and historical births need their own rules
- Separate question
- Birthplace longitude for solar time
- Required evidence
- Place, date and source clock standard
Beijing Time is a civil standard, not a Bazi doctrine
Modern official clocks across China use one UTC+8 standard commonly called Beijing Time. It provides the recorded civil timestamp for births under that rule.
The name does not mean the clock is local solar time at Beijing, and the standard meridian is 120°E rather than Beijing’s exact longitude.
- Distinguish civil standard from solar time.
- Do not infer the meridian from the city name.
The birthplace and historical date decide whether it applies
A modern birth in mainland China will ordinarily use the local official UTC+8 record. A birth in another country uses that location’s civil-time rules instead.
Older records can predate current standards or use institutional conventions. If the source says a remote event was recorded in Beijing Time, retain both that statement and the actual birthplace.
- Resolve historical rules instead of assuming today’s map.
- Keep source clock and physical place as separate fields.
UTC+8 does not remove the longitude question
Locations across a wide zone share one civil clock but sit on different meridians. If true solar time is selected, longitude correction still compares the birthplace with the standard meridian.
For overseas births, converting to the correct instant and then applying birthplace solar time is not the same as relabeling the input as Beijing local time.
- Use birthplace longitude after civil normalization.
- Avoid double-applying an eight-hour offset.
A preferred clock cannot be chosen for a preferred chart
Using Beijing Time universally can shift the date or hour for overseas births and create an internally inconsistent chart.
A difference between calculators should be resolved by aligning place, zone, solar-time and day-boundary settings—not by choosing the result with more favorable language.
- One input record, one declared clock standard.
- No result-shopping between time conventions.
Sources and editorial basis
- IANA Time Zone DatabaseIANA Asia/Shanghai 等地區規則提供中國標準時間的歷史適用範圍；其他出生地仍須使用其當地歷史時區The maintained reference for historical local-time rules, UTC offsets, and daylight-saving transitions by location.
- U.S. Naval Observatory: The Equation of Time美國海軍天文台區分標準時間與地方太陽時：UTC+8 及東經 120 度標準子午線不等於所有地點的真太陽時An official astronomical explanation of apparent solar time, mean solar time, longitude offsets, and the equation of time.
- OpenFate Editorial Methodology產品只在來源記錄或出生地民用規則適用時使用北京時間，並把記錄時制、實際地點與經度修正保存為不同欄位OpenFate separates deterministic chart calculation, traditional interpretation, and modern editorial explanation.