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Birth time correction,
and how standard time moves a pillar

Timing · September 2026 · 7 min read

Does the hour pillar use clock time as written?

Clocks are set by country, not by longitude. Everyone inside a zone reads the same face whether they sit at its eastern or western edge, so clock noon and the moment the sun peaks almost never coincide. The hour pillar ignores the clock and follows the sun.

The correction itself is simple arithmetic. Take the gap between your standard meridian and the longitude of your birth city, and add or subtract it. One degree of longitude is four minutes. East of the meridian the sun arrives early, so you add; west of it, you subtract.

How many minutes does my birth city need?

Corrections for the main cities. The sign is what you add to or subtract from the clock reading, and the result is true solar time.

Singapore is the extreme case here. The clock runs 65 minutes ahead of the sun, which means a chart cast straight from the birth certificate time is more than an hour off before anything else happens. Kuala Lumpur sits on the same clock and has the same problem. If you were born anywhere on that stretch, this is the single correction most worth making.

A Korean-style table with the boundaries already shifted for clock time lives in picking a departure hour. This article works only in corrected true solar time — where the Rat hour begins at 23:00 and the twelve two-hour blocks run from there.

Does the correction actually change the pillar?

Worked through, it looks like this.

The size of the correction decides how many people it catches. Singapore, with 65 minutes, moves anyone born in the hour before a boundary. Taipei, with six, moves only those born within six minutes of one. Same method, very different reach.

The Hong Kong row carries extra weight. The Rat-hour boundary is tied to the date, so the day pillar can move with it. On the clock that birth had already entered the Rat hour; in true solar time it had not, and the day had not turned either. If you were born around eleven at night, check the day pillar alongside the hour pillar. The schools that treat late and early Rat hour differently all trace back to this, and that fork is covered in saju, bazi and shichu-suimei.

Why do the corrections vary so much by country?

Because one standard time covers a different width of ground in each country.

• Singapore and Malaysia — the clock is set well east of the actual longitude, which is why Singapore lands at 65 minutes. It is the largest routine correction in this region.
• China — since 1949 the whole country has run on a single Beijing clock, so the gap widens the further west you go. Shanghai is +6 minutes, Chengdu −64. Two people born on the same clock reading had suns more than an hour apart.
• Korea — the standard meridian has been changed more than once and is now 135°E. Seoul sits near 127°E, producing a fixed gap of over half an hour, with the whole country skewed the same way.
• Japan — the 135°E meridian passes through Akashi, near the middle of the islands, so Osaka needs only +2 minutes and even Tokyo only +19.

Which means two people born at the same clock reading can hold different hour pillars. A birth at 07:09 in Tokyo and one at 07:09 in Seoul are nearly an hour apart by the sun.

What about daylight saving?

Korea ran daylight saving in the summers of 1987 and 1988. A birth in that window needs one hour subtracted before anything else.

Do it in order. Subtract the daylight saving hour first to get back to standard time, then apply the longitude correction. Combining the two in one step is how signs get flipped.

• Copy the time from the birth record as writtenWritten records come before recollections.
• Subtract an hour if it falls in a daylight saving windowFor Korea that is the summers of 1987 and 1988.
• Apply the city correctionSingapore −65, Seoul −32, Hong Kong −23, Tokyo +19.

Can I still read a chart without a birth time?

Yes. Only two of the eight characters come from the hour — the other six stand on the date alone.

The year, month and day pillars give you six characters as soon as you know the date. The spread of the five elements, which day stem you are, when the ten-year cycles turn — all of it comes from there. A missing hour pillar does not halve a chart. What the hour adds is mostly later life, children, and the finer texture of the mixture.

If you want to recover the time, work in order: birth certificate, hospital record, then family memory. That usually turns something up. Just know that family memory tends to be rounded to the nearest half hour, so if the remembered time sits near a boundary, it is more useful to build both charts and see which one matches the life you have actually lived than to trust the round number.

5htrip applies the longitude correction for your birth city automatically once you pick it. Without a birth time it leaves the hour pillar empty and reads the remaining six characters. It runs on a verified Manseryeok engine, so it is free every day.