Case 05 of 26

Solar-term boundaries

Before Qingming: Gregorian April is still Mao month

April 4 remains on the pre-Qingming side of the month boundary.

Boundary question

Can an April record still have the Mao Month Pillar?

Yes. The Month Pillar remains Xin-Mao (辛卯) until Qingming arrives.

Synthetic input

Recorded facts

Date
2026-04-04
Recorded time
12:00
Location
120Β°E reference meridian
Time zone
Asia/Shanghai
Longitude
120.0000Β°
Gender input
Female

Pinned expected facts

Verified output

build verified

Year

δΈ™εˆ

Month

辛卯

Day

ζˆŠη”³

Hour

戊午

Day Master
戊
True solar time
2026-04-04 11:56
Total correction
-3.44 minutes
Historical offset
UTC+08:00 Β· DST 0 min
Luck direction
ι€†ζŽ’
Reference Jie
ζƒŠθ›° Β· 2026-03-05 21:59:00
Luck start
2036-02-14 07:02:33

Reading the boundary

What this case means for your own chart

Qingming usually falls on 4 or 5 April, and it ends the Mao month. A record dated 4 April 2026 therefore still carries a Xin-Mao month even though April has begun. This is the same pattern as the Jingzhe pair, applied to a different Jie, and it confirms the rule is systematic rather than a quirk of one boundary.

The reason this matters for readers is that the first week of April is a common birth window and a common source of confusion. Someone comparing a Bazi calculator against a Chinese zodiac app in early April may see agreement on the animal and disagreement on the month, and conclude one tool is broken. Neither is; they are answering different questions.

This case also swaps the gender input relative to the Jingzhe pair, which changes the Luck Pillar direction while leaving the Month Pillar question untouched. That separation is deliberate: it lets the same page demonstrate a month-boundary fact without the direction variable confusing the picture.

The trade-off in that design is worth naming. Because gender changes at the same time as the date, this case cannot be compared directly against the Jingzhe pair to isolate a single variable. It is a month-boundary case and a direction case at once, and the two facts have to be read separately rather than inferred from a single side-by-side comparison.

Check your own record

  1. Check whether your birth date falls in the few days before Qingming, which is one of the more commonly missed Jie.
  2. Confirm your Month Pillar against the solar-term timestamp, not against the Gregorian month name.
  3. If your chart came from an app that never mentions solar terms, treat its Month Pillar as unverified near any Jie.

Which convention is in play

Calculation fact
A 4 April 2026 record returns Xin-Mao for the month, unchanged from the post-Jingzhe case, because Qingming had not yet arrived to move it past Mao.
Convention
Qingming is one of the twelve Jie used to define Bazi months. Its civil-calendar role as a public holiday in some regions is unrelated to its role here.
Our explanation
Flagging early April as a commonly missed boundary is our own observation from the cases in this suite, not a claim about how often readers actually get it wrong.

Conventions and limits

What this case does β€” and does not β€” 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 Β· sect 2 day boundary Β· BaziCalculator.ai NOAA/IANA true-solar adapter
calculation-benchmarks-v1 Β· reviewed 2026-09-05