What is Rokuyō (六曜)?

A six-day fortune cycle originating in China and adopted in Japan in the late Kamakura era (~14th century), popularised among commoners in the Edo period. The six days are: Sensho → Tomobiki → Senbu → Butsumetsu → Taian → Shakkō, repeating in that order. Still widely consulted today when scheduling weddings, funerals, moves, and shop openings.

How is Rokuyō computed?

From the lunar (旧暦) calendar by the formula `(lunar month + lunar day) mod 6`, mapped 0=Taian, 1=Shakkō, 2=Sensho, 3=Tomobiki, 4=Senbu, 5=Butsumetsu. The first day of each lunar month thus has a fixed Rokuyō (month 1 → Sensho, month 2 → Tomobiki, …, month 6 → Shakkō, month 7 → Sensho again).

How does solar ↔ lunar conversion work?

We use solarlunar (ISC license, in-browser) for years 1900-2099. The Japanese 旧暦 is a lunisolar calendar — new moons mark the first of each month, months are 29 or 30 days, and about 7 leap months are inserted every 19 years to keep the calendar aligned with the seasons. Leap months are shown as 'leap-month N'.

Which day is best for a wedding?

Taian has been the most popular by far, followed by Tomobiki (lucky morning/evening) and Sensho (lucky morning). Butsumetsu and Shakkō are typically avoided. Wedding venues often charge a premium on Taian and offer discounts on Butsumetsu, so couples not bound by tradition can save money by booking those days. This tool only reports the cycle — it doesn't tell you what to believe.

Why are funerals avoided on Tomobiki?

The characters 友引 read literally as 'pulls a friend' (to the next world), so funerals are traditionally avoided. Many crematoria in Japan are closed on Tomobiki for this reason. The original Chinese meaning (共引 = a draw, no winner) is unrelated, but the modern Japanese association is strong — worth checking when scheduling a funeral.

Does Rokuyō have a religious basis?

No. It's a folk belief, not part of Buddhist, Shinto, or any other doctrine. The Meiji government even banned it as superstition for a time, but it persisted. Whether to follow it is personal — but it's worth knowing because relatives and venue staff often do.

solarlunar (the lunar conversion library) ships a precomputed table covering 1900-2099. Dates outside this range trigger an 'out of range' error. The range is more than sufficient for practical wedding / funeral planning.

Is any data uploaded?

No. Date entry, lunar conversion, and Rokuyō calculation all run in your browser using the bundled table — nothing is sent to a server.

Back to Japanese

Rokuyō (Japanese 6-day calendar) — Taian / Butsumetsu lookup

Look up the Rokuyō (六曜) of any date — Sensho / Tomobiki / Senbu / Butsumetsu / Taian / Shakkō — and view a full month at a glance. Rokuyō is the traditional 6-day cycle used in Japan for picking auspicious days for weddings, funerals, moves, and store openings. Lunar conversion uses solarlunar (ISC); Rokuyō is computed as (lunar month + lunar day) mod 6. Includes month navigation and a per-Rokuyō meaning (Taian = all-day lucky, Butsumetsu = all-day unlucky, Tomobiki = 'pulls a friend' so funerals are avoided, etc.). Covers 1900-2099. Everything runs in your browser; no date information is uploaded.

japanesetimecalculator

How to use

1) Pick a date with the picker (defaults to today). 2) The selected date's Rokuyō (Taian / Butsumetsu / Tomobiki / Sensho / Senbu / Shakkō) and meaning / suitability are shown. 3) The month calendar lets you scan neighbouring dates — each cell shows the solar day + lunar day + Rokuyō. 4) Use Prev/Next month to navigate. Supported range: 1900-2099.

FAQ

What is Rokuyō (六曜)?: A six-day fortune cycle originating in China and adopted in Japan in the late Kamakura era (~14th century), popularised among commoners in the Edo period. The six days are: Sensho → Tomobiki → Senbu → Butsumetsu → Taian → Shakkō, repeating in that order. Still widely consulted today when scheduling weddings, funerals, moves, and shop openings.
How is Rokuyō computed?: From the lunar (旧暦) calendar by the formula `(lunar month + lunar day) mod 6`, mapped 0=Taian, 1=Shakkō, 2=Sensho, 3=Tomobiki, 4=Senbu, 5=Butsumetsu. The first day of each lunar month thus has a fixed Rokuyō (month 1 → Sensho, month 2 → Tomobiki, …, month 6 → Shakkō, month 7 → Sensho again).
How does solar ↔ lunar conversion work?: We use solarlunar (ISC license, in-browser) for years 1900-2099. The Japanese 旧暦 is a lunisolar calendar — new moons mark the first of each month, months are 29 or 30 days, and about 7 leap months are inserted every 19 years to keep the calendar aligned with the seasons. Leap months are shown as 'leap-month N'.
Which day is best for a wedding?: Taian has been the most popular by far, followed by Tomobiki (lucky morning/evening) and Sensho (lucky morning). Butsumetsu and Shakkō are typically avoided. Wedding venues often charge a premium on Taian and offer discounts on Butsumetsu, so couples not bound by tradition can save money by booking those days. This tool only reports the cycle — it doesn't tell you what to believe.
Why are funerals avoided on Tomobiki?: The characters 友引 read literally as 'pulls a friend' (to the next world), so funerals are traditionally avoided. Many crematoria in Japan are closed on Tomobiki for this reason. The original Chinese meaning (共引 = a draw, no winner) is unrelated, but the modern Japanese association is strong — worth checking when scheduling a funeral.
Does Rokuyō have a religious basis?: No. It's a folk belief, not part of Buddhist, Shinto, or any other doctrine. The Meiji government even banned it as superstition for a time, but it persisted. Whether to follow it is personal — but it's worth knowing because relatives and venue staff often do.
Why only 1900-2099?: solarlunar (the lunar conversion library) ships a precomputed table covering 1900-2099. Dates outside this range trigger an 'out of range' error. The range is more than sufficient for practical wedding / funeral planning.
Is any data uploaded?: No. Date entry, lunar conversion, and Rokuyō calculation all run in your browser using the bundled table — nothing is sent to a server.

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