Japan Calendar Today — Rokuyō, Lunar Date, Moon Age
Today's rokuyō (lucky-day cycle), traditional lunar date, moon age, observances and the countdown to Japan's next national holiday.
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What this page shows
A one-page view of today according to the traditional Japanese calendar: the rokuyō six-day luck cycle (Taian, Tomobiki, Butsumetsu and friends), the lunar-calendar date that Japan used until 1873, the moon age, the 24 solar terms, and Japan's national holidays — including a countdown to the next one. Pick any date to look up its rokuyō in advance, which is exactly what many people in Japan do before setting a wedding date or signing a contract.
What is rokuyō?
Rokuyō is a six-day cycle of lucky and unlucky days printed in almost every Japanese calendar. Taian is the luckiest day — popular for weddings; Butsumetsu is the unluckiest; Tomobiki is avoided for funerals because its characters can be read as "pulling friends along". Senshō favors the morning, Senbu favors the afternoon, and Shakkō is unlucky except around noon. The cycle is fixed to the lunar calendar: each lunar month starts on a set rokuyō and advances one step per day, which is why the sequence appears to "jump" at a lunar month boundary.
How it is computed
The lunar date follows the Tenpō-calendar rules Japan historically used: a month begins at the new moon, and its number is fixed by the solar term it contains. New moons and solar longitudes are computed with standard astronomical approximations, so the values match published Japanese calendars. Rokuyō is then derived arithmetically from the lunar month and day. Moon age is the number of days since the last new moon, measured at noon Japan time.
Notes
- Rokuyō is folk custom, not science — but it is still a real factor in Japanese scheduling etiquette.
- National holidays are derived from the holiday law itself (Happy Monday rules, equinoxes, substitute holidays), not from a stored list.
- For day counting see the Day Counter, and for business-day math the Business Days Calculator.