The Chinese almanac: what a tong shu is, and how to read a page

The first obstacle to looking the thing up is that it has half a dozen names, and each one is a small piece of history. Two of them are pronounced the same and written differently; one was changed by a pun; one was changed by an emperor's name.

The emperor's name is the best of these. The Qing court issued its calendar every year on the first day of the tenth lunar month under the title Shixian li. When the Qianlong emperor succeeded in 1735, his personal name was Hongli, and the second character of it was the character for calendar. A subject may not write the sovereign's name, so the calendar became the Shixian shu, the book of the seasons' laws, and stayed a book rather than a calendar for the rest of the dynasty. The site you are reading, 玉历, yu li, uses the character he took out of circulation. The about page explains the rest of the name.

The pun is Cantonese. Tong shu ends in the word for book, which in Cantonese sounds like the word for lose, and a book you consult before a wedding or a business opening cannot be called the book of losing. So it is the book of winning, tong sheng, and that is the word on the cover in a Hong Kong stationer's.

In December 1975, in a Qin tomb at Shuihudi in Hubei, archaeologists found the library of a county clerk named Xi, over eleven hundred bamboo slips, buried with him in a grave that his own chronicle dates to no earlier than 217 BC. Among them were two texts the excavators called daybooks: 166 slips by his head and 257 by his feet, sorting days into those suited and unsuited to marriage, travel, building and burial. That is the verdict layer of the almanac, and it predates paper and printing.

The twelve words that still head the verdict on every leaf are in a text from 139 BC. The Huainanzi, in its chapter on the patterns of heaven, runs through the twelve branches and assigns each a word: the third branch is Establish, the fourth Remove, then Full, Level, and so on through Break, Danger and Complete to Open and Close, with a note on what each group governs. In the sentence just before it, the same text places the Vermilion Bird, the Hooked Array, the Dark Warrior, the White Tiger and the Azure Dragon around the sky. Those five are, with seven others, the day spirits of the modern almanac. Both rows of the leaf you can buy this year were on the page two thousand one hundred years ago.

Then the almanac met printing, and printing met the state. The Old Book of Tang records that on a day in the twelfth month of 835, a few weeks after the Sweet Dew Incident had left the palace full of executed ministers, the court found time to order that no prefecture might privately keep printing blocks for calendars. The calendar was the emperor's to issue; it said when the year began and what each day was for, and a private printer selling it early was selling the emperor's authority. It is the earliest order regulating printing on record in China, and it is about the almanac. By 1328 the Yuan state was printing over three million copies a year of its own.

The verdict layer was finally standardized in 1739, when the Qianlong emperor, the same one whose name changed the book's title, ordered a compendium on day selection. The Xieji Bianfang Shu ran to thirty-six volumes, threw out the contradictory spirits and folk rules that had accumulated, and became the rulebook that every private almanac house has reprinted, under its own shop name, ever since.

Here is the top of a leaf for the day this page was published, with the values our engine computes for it. A printed almanac would set the same lines in a dense grid with the characters; we give them in English, in the order a Chinese reader scans them.

Three things to notice. The year, month and day lines are the top three pillars of a bazi chart, character for character; the almanac and the fortune-teller are reading the same clock. The day officer is the Huainanzi rule applied: the day whose branch matches the month's branch is Establish, and the other eleven follow in order. And the clash line is one of the six clashes of the branches: the day's branch has one opposite, and the animal of that opposite is the one the almanac warns. The sha direction follows from the same branch by a fixed table.

The full leaf runs a dozen lines. This is what each one says and where it comes from.

The two lists are the lines people actually use, and they are marked with two characters you will learn to spot on any leaf: 宜, yi, suitable, and 忌, ji, avoid. The vocabulary under them is a fixed set of a few dozen activities, most of them the big irreversible ones: marrying, moving house, breaking ground, opening for business, setting the bed, burying the dead, and traveling. A modern reader with none of the beliefs still uses the two lists the way you might use a horoscope: not to decide, but to check, and to have something to say to a grandmother who will ask.

The date layer is astronomy. The lunar month begins on the dark moon, the solar terms sit at fifteen-degree steps of the sun's path, and in modern China both are computed by the Purple Mountain Observatory under a national standard, which is what our calendar converter implements. Every almanac on every shelf agrees with every other almanac on this layer, because they have no choice.

The verdict layer is doctrine. It descends from the daybooks and the Huainanzi, was codified in 1739, and is applied by each publishing house with its own emphases, which is why two almanacs bought in the same shop can mark the same day suitable for marriage in one and silent on it in the other. That disagreement is not a flaw in one of them. It is what the verdict layer is: an interpretation printed in the grammar of a fact.

It is also why the specimen above leaves those two lines blank. We compute the date layer, because it can be computed and because we would rather you checked our lunar date against a printed almanac and found them identical. We do not print a verdict, because a verdict without the doctrine behind it is a horoscope, and we are not in that business. If you want the verdict, buy the book; it costs about as much as a coffee, it has been printed in the millions since the fourteenth century, and it is worth owning for the tables at the back alone.

The word almanac lands, for an English reader, on one book: the Old Farmer's Almanac, founded in 1792 by Robert B. Thomas, the oldest continuously published periodical in North America, with its long-range weather forecasts from a formula kept in a black tin box in New Hampshire, its planting tables, its tides and sunrises. It is a fine object, and it is a different kind of book. It predicts. A Chinese almanac predicts nothing. It classifies. It does not tell you whether it will rain on your wedding day; it tells you whether the day is one for weddings.

The Taiwan name for the Chinese book, the farmers' calendar, makes the confusion worse by making the two sound like cousins. They share a reader, since a farmer needs the solar terms and the solar terms are in both, and they share almost nothing else. The nearest thing English ever had to the verdict layer was the medieval almanac's list of good and bad days for bloodletting, and English gave that up around the time it gave up bloodletting. Chinese kept the days and dropped the leeches.