The Tongshu: Inside China's Almanac of Lucky and Unlucky Days

Ask a Chinese friend when they are getting married and there is a reasonable chance the answer involves a date that seems arbitrary — a Tuesday in an unremarkable month, chosen months in advance. Ask why that Tuesday and the answer will be some version of: we looked it up.

What they looked it up in is the Tongshu (通书), the Chinese almanac — also called Huangli (黄历), the Yellow Calendar, after the Yellow Emperor to whom it is traditionally attributed. It has been described as one of the most widely distributed books in Chinese history, and for centuries a copy sat in nearly every literate household.

What the Book Contains

A traditional Tongshu is a dense annual volume. Beyond day-by-day auspicious ratings, a full edition typically includes:

• The lunisolar calendar with all 24 solar terms
• Agricultural guidance keyed to those terms
• Zodiac and Five Element correspondences for each day
• Fengshui direction charts — where prosperity and misfortune sit each day
• Face-reading and palm-reading diagrams
• Dream interpretation tables
• Fortune outlooks by birth year animal
• Herbal remedies, charms, and occasionally a Chinese-English phrasebook in Hong Kong editions

Modern printed editions in Hong Kong, Taiwan and Southeast Asia still carry most of this. Phone apps carry the daily ratings and drop the rest.

Reading a Day Entry

The practical core is the daily entry, and it has a consistent structure. Two columns dominate:

• Yi (宜) — suitable. Activities favoured on this day.
• Ji (忌) — to be avoided. Activities that will go badly.

The activities listed are drawn from a fixed traditional vocabulary of roughly sixty categories. Common entries include:

• 嫁娶 — marriage
• 开市 — opening a business, starting trade
• 动土 — breaking ground for construction
• 入宅 — moving into a residence
• 出行 — travel
• 签约 — signing contracts
• 安葬 — burial
• 祈福 — praying for blessings
• 沐浴 — bathing, and 理发 — haircuts
• 破土 — ground-breaking for a grave

Alongside these sit several supporting fields:

• 冲 (chong) — the zodiac sign in conflict with that day. If your birth animal appears here, the day is bad for you personally regardless of its general rating.
• 五行 — the day's Five Element attribute
• 建除十二神 — the twelve day-officers, a rotating cycle of twelve day-types (Establish, Remove, Full, Balance, Stable, Initiate, Destruction, Danger, Success, Receive, Open, Close), each with characteristic suitability
• 吉神 / 凶神 — auspicious and inauspicious spirits present
• 胎神 — the position of the foetal spirit, indicating where in the house a pregnant woman should avoid disturbance

Where the System Comes From

The Tongshu is not folk invention layered onto a calendar. It is the popular residue of an official state astronomical function.

From the Han dynasty onward, calculating and promulgating the calendar was an imperial monopoly and a core symbol of legitimacy — the emperor mediated between heaven's cycles and human activity. The Imperial Astronomical Bureau computed the calendar, and printed almanacs were distributed under state authority. Producing an unauthorised almanac was, at various points, a criminal offence.

The technical machinery combines several older systems: the sexagenary cycle of ten heavenly stems and twelve earthly branches, which labels every year, month, day and double-hour; Five Element theory governing the generative and destructive relations between wood, fire, earth, metal and water; the twenty-eight lunar mansions; and the twelve day-officers.

Every daily rating is generated by combining these systems according to fixed rules. There is no discretion at the point of publication — two competently produced almanacs for the same year will substantially agree, which is a large part of the system's authority.

This is the point most sceptical accounts miss. The Tongshu is not intuition dressed up. It is a rule-based calculation applied consistently, whatever one thinks of its premises.

How People Actually Use It

Consultation clusters around a specific class of decisions: irreversible, expensive, and involving multiple parties.

• Weddings. Near-universal. Even couples who describe themselves as entirely secular usually have the date checked, often by a parent who will not accept otherwise.
• Moving house. The date and often the hour of first entry are selected. Some families carry a rice pot and a lit lamp in first, at the chosen time, before any furniture.
• Business openings. Ribbon-cuttings and first days of trading are timed. Shop signs are sometimes hung at an appointed hour.
• Ground-breaking. Construction firms in Hong Kong, Taiwan and much of Southeast Asia routinely check.
• Funerals and burials. Highly regulated by almanac timing.
• Elective medical procedures. Including, in some places, scheduled caesarean sections — a documented phenomenon around auspicious years and dates.

Equally telling is what people do not consult it for. Nobody checks the almanac before answering email. The Tongshu governs thresholds — beginnings, transitions, commitments — not ordinary days.

Dates People Avoid

Some prohibitions are widely known even among people who never open an almanac:

• Yang Gong Ji Ri — thirteen fixed "forbidden days" spread through the year, avoided for anything important.
• Po Ri — "destruction days," bad for anything constructive but sometimes chosen deliberately for demolition or ending a bad situation.
• The seventh lunar month — Ghost Month. Weddings, moving house, major purchases and swimming are widely postponed. This one has measurable economic effects on property transactions in Hong Kong and Taiwan.
• Your own zodiac clash days — personal, and taken more seriously than general ratings by many users.
• Widow years — lunar years containing no Start of Spring solar term, considered unlucky for marriage. These produce visible dips in marriage registrations.

The Modern Almanac

The Tongshu has survived the twentieth century largely intact, and the digital transition has if anything expanded its reach. Calendar apps used by hundreds of millions of Chinese phone users display yi and ji as a default field next to the date. Wedding planners, moving companies and interior fit-out firms in Hong Kong and Taiwan quote different rates for auspicious dates because demand concentrates on them.

Attitudes among users span a wide range, and it is worth being honest about it. Some believe the system describes real influences. Many more treat it as a coordination device — a neutral, external authority for settling a family argument about a wedding date, or an inherited practice observed because a grandmother would be upset otherwise. A common formulation is ning ke xin qi you — better to believe it exists than to assume it does not.

Using One

If you want to try it:

• Start with the app. Any major Chinese calendar app shows daily yi and ji.
• Check your zodiac clash first. A generally good day that clashes with your birth animal is not a good day for you.
• Match the activity precisely. "Suitable for travel" does not mean suitable for signing a lease. The categories are specific.
• Look at hours, not just days. Full almanacs rate the twelve double-hours; important actions are timed within the day.
• For anything serious, people hire a specialist. Date selection for weddings and construction is a paid professional service that accounts for the participants' birth data, not just the calendar.

Quick Reference

• Names: 通书 Tongshu, 黄历 Huangli; 通胜 in Cantonese usage, avoiding an unlucky homophone
• Core fields: 宜 (suitable) and 忌 (avoid)
• Underlying systems: Sexagenary cycle, Five Elements, 28 lunar mansions, 12 day-officers
• Historical status: State-monopoly publication under the Imperial Astronomical Bureau
• Typical uses: Weddings, moving, business openings, ground-breaking, burial
• Widely avoided: Ghost Month, Yang Gong forbidden days, personal clash days

Note on sources: this account follows the standard documented structure of the Chinese almanac and the historical role of the Imperial Astronomical Bureau in calendar promulgation. Contemporary usage patterns, including Ghost Month effects on transactions and the pricing of auspicious wedding dates, reflect widely reported practice in Hong Kong, Taiwan and Southeast Asian Chinese communities.