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Rokuyo Koyomi shows the rokuyo — the six-day fortune cycle printed on Japanese calendars — at a glance. It covers Japanese, English and Chinese, with a monthly calendar, a date lookup and a day finder. No ads, no accounts.

The rokuyo is found by adding the lunar month to the lunar day and taking the remainder after dividing by six. Because the count restarts on the first day of each lunar month, the sequence skips a step at every new moon. This site converts to the lunisolar calendar with lunar-javascript and computes every date at build time.

The boundary of a lunar month is set by the moment of the new moon, which depends on the meridian used. The calculation here follows the Chinese standard (120°E), while the Japanese traditional calendar uses JST (135°E). On rare dates the two can differ by a day. For decisions that matter — a wedding, a funeral, a formal ceremony — please confirm against an official almanac such as the one published by the National Astronomical Observatory of Japan.