The Start of Spring — when the year actually turns in these readings

2026.09.10 updated · 5 min read

In Japan the day before the Start of Spring is called Setsubun and marked by scattering beans. The two are often confused: Setsubun is precisely the day before, and the Start of Spring the day after. In the Four Pillars and in Nine Star Ki, that Start of Spring is where the year turns.

So anyone born between 1 January and the day before it is calculated as born in the previous year. The gap between the Gregorian year and the year these readings use comes from that difference in where the line is drawn.

Why not 1 January

The Start of Spring is one of the twenty-four solar terms, fixed by the position of the Sun — specifically, the moment its apparent longitude reaches 315 degrees. Being based on the movement of a body in the sky makes it a different kind of thing from 1 January, which was settled for the convenience of a calendar.

The twenty-four terms divide a year by where the Sun stands, running from the Start of Spring through the Awakening of Insects, Clear and Bright, the Start of Summer and round again. Because the Start of Spring is placed first, that is where the year begins in this calendar.

The Four Pillars and Nine Star Ki are built on the turning of the seasons. Putting the origin of the year at the start of the seasons is what makes the system consistent. That is why 1 January is not used.

The date shifts every year

The Start of Spring is often remembered as 4 February, and in some years it falls on the third. Because the time the Earth takes to go round the Sun is not exactly 365 days, it drifts a little each year.

Look at 2025. The Start of Spring comes late in the evening of 3 February. Anyone born on that day that year falls on one side or the other depending on the time of birth. Deciding by the date alone would place them wrongly.

How this service handles it

Rather than looking the date up in a table, this service calculates it from the position of the Sun. That lets it decide for years no table would cover, and it means the Four Pillars and Nine Star Ki never disagree.

The same thinking applies to the turn of the month, not only the year. The month pillar in the Four Pillars changes over at a solar term rather than on the first. Anyone born early in a month may find the calendar month is the previous one.

For a birth on the day of the term itself, whether it fell before the moment cannot be decided without a time of birth. Since this service does not ask for one, the result carries a note rather than picking a side.

In some years Setsubun falls on 2 February

Setsubun is the day before, so in a year when the Start of Spring falls on 3 February, Setsubun falls on the second. That happened in 2021. The date of the bean-scattering moves for exactly this reason.

Common questions

I was born in February. Do I count as the previous year?

If you were born before the Start of Spring, yes. It falls on either 3 or 4 February, so anyone born in the first days of the month should check the term for their own year of birth.

Does Western astrology use the Start of Spring too?

It does not. Western astrology takes the vernal equinox as its origin. The Start of Spring is used by the eastern methods — the Four Pillars, Nine Star Ki and the like.

Why scatter beans at Setsubun?

It comes from a custom of driving off ill influences at the turn of a season. That is a separate matter from the calculation, although it marks the same boundary: the day before the Start of Spring.