Case 12 of 26
True-solar crossings
Kashgar: correction crosses into the previous day
A far-western longitude within China Standard Time produces a large negative correction.
Boundary question
Can 01:30 civil time become the preceding solar date?
Yes. The normalized true solar time is 22:41 on the previous date, so the chart is calculated from that corrected wall time.
Synthetic input
Recorded facts
- Date
- 2025-12-10
- Recorded time
- 01:30
- Location
- Kashgar, China
- Time zone
- Asia/Shanghai
- Longitude
- 75.9898°
- Gender input
- Male
Pinned expected facts
Verified output
Year
乙巳
Month
戊子
Day
壬子
Hour
辛亥
- Day Master
- 壬
- True solar time
- 2025-12-09 22:41
- Total correction
- -168.72 minutes
- Historical offset
- UTC+08:00 · DST 0 min
- Luck direction
- 逆排
- Reference Jie
- 大雪 · 2025-12-07 05:04:37
- Luck start
- 2026-11-06 23:59:16
Reading the boundary
What this case means for your own chart
Kashgar sits at roughly 76°E while China's clocks run on the 120°E meridian, a gap of about three hours of solar time. A record logged at 01:30 in the morning corrects back to 22:41 on the previous calendar date. That is not a rounding difference; the day pillar changes.
The day pillar is the pillar the Day Master is read from, and the Day Master is the anchor the rest of a traditional reading is built around. Moving it by one day changes which stem governs the chart, which in turn changes the Ten Gods relationships throughout. This is the most structurally disruptive correction in the suite.
Readers born in far-western China, and anywhere else where civil time is offset far from local solar time, should treat a late-night or early-morning birth record as genuinely uncertain about its date. The clock says one day; the sun says the day before.
This is also the case that makes the strongest argument for recording birth times with their location. A time without a place cannot be corrected, and an uncorrected time in this region can be wrong by a whole calendar day. The correction is not an optional refinement layered on top of the data; it is part of what the data means.
Check your own record
- If you were born between roughly 22:00 and 02:00 in a region far west of its timezone's standard meridian, check whether the correction crosses midnight.
- Compare your birth city's solar time offset against the standard meridian before accepting the calendar date on your record.
- If the corrected time crosses midnight, expect the day pillar, the Day Master, and every Ten Gods relationship to differ from a naive calculation.
Which convention is in play
- Calculation fact
- The pinned engine returns 22:41 on the preceding date for this 01:30 Kashgar input, a correction of about −169 minutes, and derives the chart from that corrected wall time.
- Convention
- That the day pillar follows the corrected solar date rather than the civil date is this engine's stated convention. It is a genuine point of divergence between practitioners.
- Our explanation
- Our advice to treat late-night records in far-western regions as date-uncertain is a practical caution we are adding, not a rule from the tradition.
Related reading
Conventions and limits
What this case does — and does not — prove
It verifies
Deterministic reproduction of this input under the named engine version and conventions. A pinned-field mismatch stops the production build.
It does not claim
Universal agreement across Bazi schools, interpretation of a real person, or certainty where the historical record is incomplete.
tyme4ts 1.5.2 · cantian-tymext 0.0.27 · sect 2 day boundary · BaziCalculator.ai NOAA/IANA true-solar adapter
calculation-benchmarks-v1 · reviewed 2026-09-05