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曜

Day of Week Finder

Weekday and Japanese rokuyo for any date.

Weekday
Monday

月曜日 · ISO 1

Rokuyo
赤口Shakko

Mostly unlucky; only noon is considered lucky. Caution with fire and blades.

Lunar (kyureki)
2023-11-20
Day of year
1/366
ISO week
2024-W01
Reading
しゃっこう
Rokuyo cycle
先勝友引先負仏滅大安赤口

Rokuyo is derived from the Japanese lunisolar (kyureki) month and day via (month+day−2) mod 6. Kyureki uses the classic Takano/Nagano QREKI approximation; dates near a new-moon boundary may differ by one day from official calendars. Treat auspiciousness as folklore, not advice.

About Day of Week Finder

Weekday lookup is everyday scheduling basics. In Japan, rokuyo (Taian, Tomobiki, Sensho, Senbu, Butsumetsu, Shakko) is still consulted for ceremonies. Rokuyo is determined solely by the lunisolar month and day. Pick a Gregorian date in toco.tools to see the weekday, ISO weekday number, kyureki (lunar) date, rokuyo name with reading and a short meaning, day-of-year, and ISO week—all in your browser. Kyureki uses the classic Takano/Nagano QREKI approximation; dates near a new-moon boundary may differ by one day from official almanacs. Treat auspiciousness as folklore and confirm important plans against an official calendar.

How to use

  1. Pick a date (or use Today)
  2. Review weekday, rokuyo, and lunar date
  3. Optionally note meaning, day-of-year, and ISO week

FAQ

How is rokuyo calculated?

From the lunisolar month and day: (month+day−2) mod 6 maps to Sensho, Tomobiki, Senbu, Butsumetsu, Taian, Shakko.

Is the lunar date exact?

It uses the QREKI (Tenpō-style) approximation. Most dates match official almanacs; new-moon boundaries can be off by one day.

Is my date sent anywhere?

No. All calculation runs in your browser.