Koyomi 1.7.0

The "Koyomi" app offers comprehensive calendar features tailored to traditional Japanese timekeeping and date calculations. It allows users to load and display standard calendars, providing a detailed view of dates, weekdays, zodiac signs (eto), nine-star astrology (kuusei), lunar calendar details, tide names, historical days, full-day indicators, the twenty-eight constellations (nijushin), middle and lower segments.

The app also displays lunar phases and moon age, supporting printing of calendars through both a built-in function and the "Rolt" printing system. It includes an age fast-reference table and enables sharing calendars as PDF files via "Open in..." or other apps using activity sharing. Furthermore, it supports widget integration for quick access in the Notification Center's "Today" view.

Users can choose from multiple display formats: monthly, yearly, or list views. Advanced search functions allow filtering by seasonal solar terms (sekki), seventy-two microseasons (kō), miscellaneous festivals (zassetsu), specific dates, zodiac signs, and public holidays. Daily sunrise and sunset times are also available, along with a landscape-oriented display mode for easier viewing.

Historically, Japanese calendars include elements like zodiac signs, nine-star astrology, six-day cycles (rokuyou), and twenty-four solar terms—all providing auspicious or inauspicious designations for specific days. For example, Daian day is considered favorable for weddings, travel, moving, and opening businesses; butotsumetsu (Buddha's death day) is regarded as an inauspicious day for all activities; senkachi days are good for urgent matters early in the day but bad in the afternoon; senbye is a day of quietude where competitive and urgent activities are discouraged but are favorable in the afternoon; tomobiki is auspicious in the morning and evening but inauspicious at noon, especially for funerals; and red mouth days are generally inauspicious for any work but may be fine around noon.

The zodiac cycle (eto) combines ten heavenly stems (kanshi) with twelve earthly branches (jūni-shi) to form a 60-year cycle used to determine auspicious dates and directions. The twenty-four solar terms divide the sun’s annual journey into 24 segments, serving as seasonal indicators especially useful when lunar calendar dates diverge from actual seasons.

"Koyomi" provides an easy way to access these traditional Japanese calendar elements on your iPhone. Even those indifferent to astrology or calendar traditions will find it helpful; for instance, confirming if a wedding date aligns with an auspicious day is valuable information. In our goal-oriented society focused on efficiency and results, starting important endeavors on lucky days can be beneficial. Usage is straightforward—simply open the app to see all zodiac signs, nine-star insights, six-day cycles, solar terms, and other traditional indicators at a glance. It also imports data from the standard iOS calendar so users can manage schedules alongside traditional dates. Additionally, calendars can be printed or shared easily. The app is compatible with watchOS for quick access on Apple Watch.