🧮 Calculators & Daily Life

Zassetsu Calendar (Doyō, Higan, Nyūbai)

Pick a year to list setsubun, hachijūhachiya, nyūbai, hangeshō, doyō, the ox days of summer doyō, higan and shanichi. Same astronomical engine as the 24 solar terms, with a baked lookup for this year and next.

MarkerDate

Zassetsu dates in 2026 and 2027

Zassetsu are seasonal markers placed between the 24 solar terms. Setsubun is the day before Risshun; hachijūhachiya and nihyakutōka count from Risshun; nyūbai, hangeshō and doyō follow solar longitude (nyūbai is not the JMA rainy-season start); higan is three days either side of the equinox; shanichi is the nearest Elder Earth stem day (a tie uses morning → earlier, afternoon → later). Below are 2026 and 2027.

2026

MarkerDate
SetsubunFeb 3 (Tue)
RisshunFeb 4 (Wed)
HachijūhachiyaMay 2 (Sat)
NyūbaiJun 11 (Thu)
HangeshōJul 2 (Thu)
Spring higanMar 17 (Tue) – Mar 23 (Mon)
Spring shanichiMar 25 (Wed)
Spring doyōApr 17 (Fri) – May 4 (Mon)
Summer doyōJul 20 (Mon) – Aug 6 (Thu)
Ox day(s) of summer doyōJul 26 (Sun)
NihyakutōkaSep 1 (Tue)
NihyakuhatsukaSep 11 (Fri)
Autumn higanSep 20 (Sun) – Sep 26 (Sat)
Autumn shanichiSep 21 (Mon)
Autumn doyōOct 20 (Tue) – Nov 6 (Fri)
Winter doyōJan 17 (Sat) – Feb 3 (Tue)

2027

MarkerDate
SetsubunFeb 3 (Wed)
RisshunFeb 4 (Thu)
HachijūhachiyaMay 2 (Sun)
NyūbaiJun 11 (Fri)
HangeshōJul 2 (Fri)
Spring higanMar 18 (Thu) – Mar 24 (Wed)
Spring shanichiMar 20 (Sat)
Spring doyōApr 17 (Sat) – May 5 (Wed)
Summer doyōJul 20 (Tue) – Aug 7 (Sat)
Ox day(s) of summer doyōJul 21 (Wed), Aug 2 (Mon)
NihyakutōkaSep 1 (Wed)
NihyakuhatsukaSep 11 (Sat)
Autumn higanSep 20 (Mon) – Sep 26 (Sun)
Autumn shanichiSep 26 (Sun)
Autumn doyōOct 21 (Thu) – Nov 7 (Sun)
Winter doyōJan 17 (Sun) – Feb 3 (Wed)

How to use

Pick a year to list zassetsu — seasonal markers between the 24 solar terms. The static table below is this year and next, baked at build time.

Example (2026)

  • Setsubun — 3 Feb (the day before Risshun on 4 Feb)
  • Hachijūhachiya — 2 May
  • Nyūbai — 11 Jun (solar longitude 80°; not the JMA rainy-season start), hangeshō — 2 Jul
  • Ox day of summer doyō — 26 Jul (one day)
  • Spring higan — 17–23 Mar (midpoint is the equinox on 20 Mar)
  • Spring shanichi — 25 Mar (the equinox is at night; the two Elder Earth days 15 and 25 Mar are equally far, so afternoon takes the later day)

Related tools

24 solar terms: nijūshi sekki. Rokuyo: rokuyo calendar. The ox-day list for this year and next is in the table below.

FAQ

Is my data sent to a server?
No. Zassetsu dates are computed in your browser; nothing is transmitted or stored externally.
How are setsubun and hachijūhachiya defined?
Setsubun is the day before Risshun. Hachijūhachiya, nihyakutōka and nihyakuhatsuka count days from Risshun as day 1.
Can a year have two ox days of summer doyō?
Yes. Summer doyō runs from solar longitude 117° until the day before Risshū. A year with two ox days in that span has a first and second ox day.
What is the difference between higan and shanichi?
Higan is the seven days centred on each equinox (three days either side). Shanichi is the Elder Earth stem day nearest the equinox. If two stem days are equally far, a morning equinox takes the earlier day and an afternoon equinox takes the later day (the usual rule since the Meiji 14 calendar). The 2026 vernal equinox is at night, so spring shanichi is 25 March.
Is nyūbai the same as the rainy-season start?
No. Nyūbai is the calendar day when the Sun reaches 80° ecliptic longitude. It is not the Japan Meteorological Agency’s rainy-season onset, which is announced separately and can differ by days or weeks.
Which years are supported?
1900–2099, using the same solar-longitude engine as the 24 solar terms.