似曾相识

Twentieth of December, 2038, a Monday, morning, Turpan. It snowed in the night. It hardly ever snows in Turpan; Aynur says the last time it lay this thick was years ago, she can't remember which. I'd come in late from Urumqi, the snow starting at the Dabancheng wind gap, white flakes flinging themselves at the windscreen. This morning the yard was white; the buried vines in their mounds lay under snow like a row of sleeping sheep; the drying house roof white, the holes in its walls black against it. Beside the door frame leaned a pole: taller than a man by a long way, the shaft dark and slippery the way only many years of many hands make wood, forked at the head, the fork worn shiny. Alim found it last month mending the roof of house three, wedged between the ridge beam and the wall under a finger's depth of dust; he wiped it three times. "My father saw it and held it with his left hand all afternoon." Yasen, back from Urumqi with his mother, saw the snow, shouted, ran into it with his shoes half on, fell, got up, ran, and stopped before the pole. He hugged it up in both arms; it was too long for him; the fork swung and dumped snow down his neck; he hunched and laughed and would not let go. At the window, in his wheelchair, his grandfather watched, the fingers of his left hand tapping softly on the armrest. It was his birthday.

Near noon, sweeping a path for the wheelchair, I found under the grape trellis a short, fair, middle-aged man in a plain padded gown, cuffs neat, hands empty, looking up at the snow lying along each bar of the bare trellis. "Last year's weather, the same old pavilions." Yan Shu, of Linchuan in Fuzhou; a writer of lyrics. "I seem to have been in this yard before." You haven't. "No. But it looks like it." He pointed to an empty swallows' nest under the eaves of house three. "I once wrote a little song about a garden a year on: same weather, same pavilions. Flowers fall, nothing to be done; swallows come back and look like ones I know. They aren't last year's. Swallows don't live that long. Last year's, this year's, next year's look alike. What they know is the nest." After the pilaf, Guli opened a box: the thirty-one letters, copied, red-penned, margins full. "There are over a hundred rules in the book. In Turpan, in our house, nearly all of them work. Elsewhere, eleven don't." East wall first: in Hami the wind comes from the north, and the strings stayed damp. Touch the top string the day before: works everywhere. Spacing by the year's rain: in Dunhuang there is hardly any rain; he spaces by wind. "These rules were made in our houses, looking at our grapes. That they work in our house is no surprise. They were made from it."

Yan Shu, on a stool by the door: "I met this as a boy. At fourteen they sent me to the capital to be examined beside a thousand grown men. I passed. Two days later another paper; I looked at the topic: I'd written on it at home ten days before, the draft still there." Lucky, said Yasen. "I stood up and told the emperor: I wrote this ten days ago; please set another." Why? You knew it! "That's why. However well I wrote, he'd be seeing what I'd worked out slowly at home. What he wanted was how I'd write facing a question I'd never seen. A question you've seen, answered right, doesn't count." Guli wrote: "What works in our house is the question we've seen. Whether it works elsewhere is the exam." At three, before the cake, the old man sent for the pole and gave it to Yasen. In the cold empty house three, Yasen said first: "Grandpa, I practised on the nails in the yard with plastic beads. The bottom rows I can reach; I've practised those." His grandfather pointed up, to the very top row of the east wall, which Yasen could neither reach nor had practised. First try the string slid off and lost a few raisins; he went red, picked them up, didn't cry; his grandfather's hand stopped Alim from helping. Second try: string in the crook, pole along the wall, up and up, a flick of the wrist at the nail, and it hung there, top of the east wall. He stood mouth open, looking up, exactly as a man on a ladder had looked up after one flick of his right hand, the first year I came. Then a pen, left hand, a long time: 来. Come. Alim: next year. Guli: to me, 10 March, for the weighing. Yasen: "No. He pointed at the swallows' nest. He means they'll come." Aynur wrote the date on the back in pencil. Ten years ago, on Jiuyan Bridge in Chengdu, a piece of green jade fell at my feet with the English for that word on its back; later, in a teahouse, it turned into sixteen seal characters ending in this same 来. I haven't thought of it in years. I can't think where it is. — M.

Memo to file. Turpan, 20 December 2038. The question you've already seen.

1. Snow in Turpan. Rare enough that Aynur can't remember the last time. Vines under mounds like sleeping sheep; the drying house roof white; two strings on the door frame bowed under snow.

2. The pole. Found last month wedged between ridge beam and wall: taller than a man, slick with many hands, forked, the fork worn shiny. The old man held it all afternoon with his left hand.

3. The swallows. Yan Shu under the bare trellis: "Flowers fall, nothing to be done; swallows come back and look like ones I know. They aren't last year's; swallows don't live that long. What they know is the nest."

4. Guli's audit. Thirty-one readers' letters against a hundred-odd rules: in our house nearly all work; elsewhere eleven don't. East wall first fails where the wind comes from the north; spacing by rain fails where there's no rain; touching the top string the day before works everywhere.

5. Her diagnosis. "These rules were made in our houses from our grapes. That they work here is no surprise." I had taken "all of them work" as proof the rules were good. It was proof only that they fit the data they were made from.

6. The boy at the exam. Yan Shu at fourteen: the second paper's topic he'd written on ten days before. He told the emperor and asked for another. "However well I wrote, it would be what I'd worked out at home. A question you've seen, answered right, doesn't count." The emperor changed it, pleased the boy hid nothing.

7. Guli's line. "What works in our house is the question we've seen. Whether it works elsewhere is the exam." The letters are the out-of-sample test the book never had.

8. The Wall Street version. A model that was magnificent in backtest and lost money the first live quarter. The team had tuned it, without meaning to, on the very years they tested it on. One researcher had said: "I've already looked at that period; it doesn't count." He was the least popular man on the floor.

9. Yasen's honesty. Handed the pole and a string: "I practised the bottom rows with plastic beads; I've done those." His grandfather pointed to the top of the east wall: unreachable, unpractised.

10. The new question. First try: the string slid off, a few raisins lost; red face, no tears; the old man's hand held Alim back. Second: string in the crook, pole along the wall, a flick at the nail. Top of the east wall. His upturned face was the face of a man on a ladder the first year I came.

11. The word. Left hand, a long time: 来. Come. Next year, says Alim; for the March weighing, says Guli; the swallows, says Yasen, because Grandpa pointed at the nest. Aynur pencilled the date on the back.

12. Next. That word was once on the back of a piece of jade, in English, on a bridge in Chengdu, ten years ago; its sixteen characters end in this same 来. I can't think where the jade is now. Before that: Fresno, 8 January. Martin: "Ribbon's still on. Bring your hands." The black stub is waiting.

"I wrote on this very topic ten days ago and still have the draft; I beg you to set another."
Yan Shu, the Song poet best remembered for the line about swallows that "come back, and I seem to know them," was examined at court as a boy of fourteen. When the second paper turned out to be on a topic he had already practised at home, he told the emperor and asked for a different one. The emperor, records Shen Kuo, "loved him for not hiding it."
Any set of rules derived from experience will fit the experience it was derived from. A hundred practices refined in one family's drying houses will look almost flawless in those same houses; a trading model tuned on a decade of data will look brilliant on that decade. Neither fact says much about how the rules will perform anywhere else.
The honest move is to separate the questions you have already seen from the ones you haven't, and to judge your rules only on the latter. Letters from strangers who tried the rules in other places, with other winds and other rains, are worth more than another season of success at home.
"A question you've seen, answered right, doesn't count."