The Year Pillar: Why the Year Turns at Lichun

The year pillar is the stem-branch pair of the year you were born in, but the pillar year does not start on 1 January or on Lunar New Year. It starts at the solar term 立春 (lichun, Start of Spring), the moment the sun reaches 315 degrees of longitude.

What the year pillar is

Every year carries one of the sixty stem-branch pairs. 2026, for example, is 丙午: the stem 丙 is yang Fire and the branch 午 is the Horse. The branch is where the familiar zodiac animal comes from. In the Four Pillars the year pair is the outermost of the four layers, and the tradition reads it as the broad background of a chart, the way a season frames a single day.

Working out which pair a year carries is simple arithmetic, explained on the sixty cycle page: (year - 4) mod 10 gives the stem and (year - 4) mod 12 gives the branch. The part that needs care is not the arithmetic but the question of when a year begins.

Lichun is the boundary

The Four Pillars follow the sun, not the moon and not the civil calendar. The solar year is divided into 24 solar terms, and the first of them, 立春, marks the start of spring and the start of the pillar year. 立春 falls when the sun's apparent longitude reaches 315 degrees, which lands on 3 or 4 February.

In 2026, 立春 fell at 05:02 on 4 February, Korean Standard Time. Everything born before that moment belongs to the 乙巳 year (the Snake), and everything born after it belongs to the 丙午 year (the Horse). The haru engine checks this against the exact instant in universal time, so a birth in any city is compared with the same astronomical moment and then shown in local time.

Two common calendars give different answers. On 1 January 2026, the engine still gives the year pillar 乙巳, because 立春 has not yet arrived. Lunar New Year 2026 fell on 17 February, almost two weeks after 立春, and the engine already gives 丙午 on that day. So a person born between 4 and 17 February 2026 has a 丙午 year pillar even though, by the lunar calendar, the old year had not yet ended.

Two births a few hours apart

The clearest way to see the boundary is to compare two births in Seoul on the same date, 4 February 2026: one at 03:00, about two hours before 立春, and one at 09:00, about four hours after it. The engine reports the distance to the nearest term as -2.1 hours and 4.1 hours.

What changes and what stays

Both the year and the month change at 立春, because 立春 is also the first of the twelve month boundaries: the month moves from 己丑 to 庚寅. The day pillar, 己酉, is the same for both births, since the day count has nothing to do with solar terms. The hour pillars differ only because the clock times differ.

Because a whole year pair and a month pair flip within a few hours, the tradition treats births near 立春 with extra care. The haru engine measures how many hours a birth lies from the nearest boundary term so that such cases can be noted, and a reliable birth time matters most here.

Lichun times, 2020 to 2030

The exact time of 立春 shifts from year to year. It moves roughly six hours later each year and then steps back by about a day after a leap year: 2024 fell on 4 February at 17:27, while 2025 fell on 3 February at 23:10. The same pattern shows after 2020 and 2028. That is why no fixed date can be used as the year boundary.

Questions

I was born on 20 January. Which year pillar do I have?

In this tradition you take the pair of the previous year, because 立春 comes in early February. For example, 1 January 2026 still carries the 乙巳 year pillar.

Why not use Lunar New Year?

The Four Pillars are a solar reckoning. The months are set by the sun's position, and the year starts with the first of those months at 立春. Lunar New Year belongs to the lunar calendar and moves by several weeks from year to year; in 2026 it fell on 17 February.

Does my time zone matter?

The engine compares the birth with 立春 as a single instant in universal time. The times on this page are in Korean Standard Time; for a birth elsewhere, the same instant simply shows a different clock time.

Does my zodiac animal follow the same rule?

In the Four Pillars, yes: the animal is the year branch, so it also changes at 立春. Popular calendars sometimes change the animal at Lunar New Year instead.

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Traditional Four Pillars (myeongni) and yin-yang five-element interpretation. Not a medical diagnosis or advice.