问清日历 - Wenqing Calendar

A fully offline Chinese lunisolar calendar. Solar terms to the second, every entry traceable to its rule. No account, no ads, no data collection.

Wenqing Calendar is a fully offline reference tool for the Chinese traditional calendar — the lunisolar calendar that has ordered dates in East Asia for well over a thousand years, rendered here with a modern astronomical engine.

THE CALENDAR ITSELF

• Lunisolar calendar for 1900-2100: Gregorian dates alongside lunar months and days, with leap months handled correctly
• All 24 solar terms (jieqi) computed astronomically and shown to the second, never rounded to the day
• Sexagenary (ganzhi) notation for year, month and day - the traditional Chinese way of naming a date
• Daily almanac annotations in the tradition of Chinese printed calendars: the Twelve Day Officers (jianchu), the day's presiding officer, the 28 lunar mansions, and the customary suitable/unsuitable activity notes

TWO WAYS TO READ A MONTH

• Month grid: a familiar seven-column calendar, each day corner-marked with its Day Officer
• Almanac scroll: one day per line, modeled on the annotated calendar manuscripts recovered at Dunhuang, with a Day Officer filter for scanning a whole month at once
• Pinch to switch between them; the app remembers which you prefer

EVERY ENTRY SHOWS ITS WORK Any annotation can be expanded into its derivation: the canonical formula worked through with the actual values (Day Officer = (day branch - month branch) mod 12), the ledger the entry came from, and the convention settings currently in force. Nothing is asserted without the rule behind it.

TRUE SOLAR TIME, MADE VISIBLE A twelve-hour band across the day places true solar noon against clock noon, offset by the equation of time - computed in the app, not copied from a table.

SEASONS AND SKY

• The 72 pentads: the traditional division of the solar year into five-day periods, each carrying a short phenological note - a one-line record of what was observed in nature at that point in the season. The current pentad is printed on every day sheet and marked at its first day in the scroll view.
• The Nine-Nines winter count: the customary 81-day tally from the winter solstice to the end of deep winter, drawn as an outlined plum blossom of 81 petals. Fill in one petal a day; when the last is filled, the count is out.
• The moon's phase for each day, drawn in ink beside the lunar date, and a whole-month phase scroll one tap away.

ACCURACY IS THE PRODUCT

• The day boundary follows the traditional 23:00 convention by default; the midnight convention is one tap away, and both are documented rather than silently assumed
• The Twelve Day Officers are derived from the canonical rule and stay correct on solar-term transition days, where widely used third-party almanac data is commonly wrong
• The calendrical engines are locked by 500+ automated golden tests

PRIVATE BY DESIGN

• 100% offline. Works in Airplane Mode. The binary contains no networking code at all.
• No account, no sign-up, no analytics, no advertising, no in-app purchases
• App Privacy: Data Not Collected

WIDGETS Home Screen and Lock Screen widgets show today's Gregorian and lunar date with the day's calendrical annotations, updated on device.

The interface is in Simplified Chinese.