Year pillar at Ipchun, month pillar at solar terms
In the Four Pillars, the year changes at the exact moment of Ipchun (Start of Spring, around February 4) — not on January 1 or Lunar New Year — and each month changes at one of the 12 jeol solar terms, not on the lunar 1st. That is why many January and early-February births use the previous year's pillar, and births early in a month can use the previous month's pillar.
The 12 terms that start each month
Dates move by about a day between years; the exact term time is what counts.
| Month branch | Solar term | Approx. date |
|---|---|---|
| 寅 Tiger | Ipchun (Start of Spring) | around Feb 4 |
| 卯 Rabbit | Gyeongchip (Awakening of Insects) | Mar 5–6 |
| 辰 Dragon | Cheongmyeong (Clear and Bright) | Apr 4–5 |
| 巳 Snake | Ipha (Start of Summer) | May 5–6 |
| 午 Horse | Mangjong (Grain in Ear) | Jun 5–6 |
| 未 Goat | Soseo (Minor Heat) | around Jul 7 |
| 申 Monkey | Ipchu (Start of Autumn) | Aug 7–8 |
| 酉 Rooster | Baengno (White Dew) | Sep 7–8 |
| 戌 Dog | Hallo (Cold Dew) | around Oct 8 |
| 亥 Pig | Ipdong (Start of Winter) | around Nov 7 |
| 子 Rat | Daeseol (Major Snow) | around Dec 7 |
| 丑 Ox | Sohan (Minor Cold) | Jan 5–6 |
Born on a term day? Check the time
A solar term starts at a specific minute. If Ipchun begins at 5 pm, a morning birth that day still uses the previous year and the Ox month; an evening birth uses the new year and the Tiger month.
Why the winter solstice date can differ
Mid-month terms like the winter solstice are also moments in time. When one falls near midnight, calendars using different reference time zones (Korea vs. China, for example) show it on the 21st or the 22nd. Same astronomy and same time zone give the same result.
How to check
- See whether the birth date is near Ipchun or the start of a month term.
- Look up that year's term time to the minute.
- Compare with the corrected birth time to set the year and month pillars.
In Myeongsik Note
Myeongsik Note calculates solar terms astronomically to the minute, changing the year at Ipchun and months at each term. Terms appear on the day-pillar calendar, and each monthly pillar shows the date it begins.
Note
Saju (Four Pillars) is traditional calendar culture. This guide explains how charts are calculated, for reference and study only. It does not predict or guarantee anything, and conventions differ between schools and calendars.
A saju calendar that shows every term date
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