Preparing your birth details

What each detail unlocks

This is why WEAVEN lets you save a profile with only a date: it can already calculate the pillars that do not depend on the hour and the planets that do not move much in a day, and it labels everything else as withheld.

Where to find a recorded birth time

• Birth certificates and hospital records. Many jurisdictions record the time of birth on the long-form certificate or the hospital's discharge summary, sometimes to the minute. Short-form certificates often omit it.
• Family records. Baby books, letters, a parent's diary, or the red-egg announcements common in Chinese families often note the hour.
• Memory, with caution. "Around dinner time" is useful information; enter it as a range rather than a single minute.

A time written on a certificate is the local clock time at the hospital. That is exactly what you should enter; the app converts it using the time zone of the birthplace on that date.

Why the time zone of the birth year matters

Astronomical positions are computed in universal time, and the hour pillar depends on local solar time, so the clock time must be converted using the rules that applied where and when you were born, not today's rules. Time-zone boundaries and daylight-saving practices have changed repeatedly. Mainland China, for example, observed daylight-saving time only from 1986 to 1991; a summer birth in Beijing in 1988 recorded as 15:00 corresponds to 14:00 standard time, which can move the hour pillar to the previous 时辰. WEAVEN resolves historical offsets and daylight-saving automatically from the birthplace and lets you mark a recorded time as standard time if you know daylight-saving was not applied.

The rules come from the IANA Time Zone Database, which documents historical offsets and transitions for every region and is the reference used by most operating systems. If the profile has no recognisable time zone, the chart says that clock time was used as universal time, so you know which factors to trust.

True solar time and the hour pillar

Classical BaZi divides the day into twelve double-hours (时辰) by the Sun's position, so many practitioners correct the clock time to true solar time using the birthplace's longitude and the equation of time. Across a wide zone such as China Standard Time (based on 120° E) the correction can exceed an hour in the far west. WEAVEN applies it when coordinates are known and reports when the correction shifts the hour pillar, or even the day pillar across midnight. Not every school applies this correction; the chart states the method so a practitioner can adjust.

Lunar dates

If you only know the lunar date, enter it as lunar and mark whether it fell in a leap month. The app converts it to the Gregorian date and records that a conversion was made. BaZi itself does not use the lunar month for the pillars: months change at the solar terms, and the year changes at 立春 (roughly 4 February), which is why a person born in late January can have the previous year's animal in the classical system. WEAVEN shows both rules when they differ.

When the time is unknown or approximate

1. Choose "unknown" rather than guessing. An invented time produces a confident-looking chart with a possibly wrong Ascendant, houses and hour pillar.
2. If you know a window, enter it as a range. WEAVEN uses the midpoint, marks the chart medium confidence, and warns when the Ascendant could differ at either end.
3. Read the caveats under the chart. They list exactly which factors were withheld or approximated.
4. Ask the advisor questions that do not depend on the hour: element balance, Day Master, luck-cycle themes, Sun and Moon placements, transits.

Checklist before you save a profile

• Date, and whether it is Gregorian or lunar.
• Time as recorded, or a range, or "unknown".
• Birthplace chosen from the list so that coordinates and time zone are filled in.
• Gender only if you want the direction of the luck cycles.
• A label instead of a full name if you prefer; the chart does not need a name.