Rokuyō Calendar — Taian, Butsumetsu & Lucky Days
Check the rokuyō (Taian, Tomobiki, Butsumetsu…) for any date with a month calendar view — the traditional lucky-day cycle used for Japanese weddings and ceremonies.
🔒 Runs entirely in your browser. Your input and output are never sent to a server or stored — fully private.
Rokuyō calendar
Rokuyō is derived from the old lunisolar (kyūreki) date, computed here with an astronomical approximation. Dates near a lunar-month boundary can differ from official almanacs — for weddings or funerals, double-check a printed calendar. Cultural tradition, not a prediction.
About this tool
This rokuyō calendar shows the traditional six-day fortune cycle — Taian, Tomobiki, Senshō, Senbu, Shakkō and Butsumetsu — for any date, plus a full month grid, computed in your browser. Rokuyō comes from the old lunisolar calendar and is still printed in many Japanese calendars and consulted when picking dates for weddings, funerals, moving house or opening a business: Taian is considered the luckiest, Butsumetsu the least. The tool derives the old-calendar month and day astronomically and maps them to the cycle. Nothing you look up is sent anywhere.
Frequently asked questions
What does each rokuyō day traditionally mean?
Traditionally: Taian is lucky all day — the favourite for weddings; Tomobiki is good except at noon, but avoided for funerals (the name suggests "pulling friends along"); Senshō favours the morning, Senbu the afternoon; Shakkō is unlucky except around noon; and Butsumetsu is the least auspicious, often avoided for celebrations — though venues can be cheaper then. These are customary readings, not rules.
How is rokuyō calculated?
It follows the OLD lunisolar calendar, not the Western one. The first day of old-calendar month 1 is Senshō, month 2 starts with Tomobiki, and so on; within a month the cycle advances one step per day. That is why rokuyō appears to "jump" in the modern calendar — every old-calendar month boundary resets the sequence. This tool computes the old-calendar month and day from astronomical new-moon calculations, then applies that rule.
Can the result differ from a printed calendar?
Rarely, yes — around old-calendar month boundaries. The conversion depends on the exact instant of each new moon, and different almanacs can disagree by a day near those edges. For an ordinary date check this tool is plenty; for a once-in-a-lifetime ceremony like a wedding, it is sensible to double-check against the venue's or a published almanac. And remember rokuyō is folk custom — a Butsumetsu wedding is not doomed. Nothing you enter leaves your browser.