From the back of a flour merchant's order form, in Su Wenxi's handwriting: "AGREEMENT OF TEMPORARY COOPERATION between Su Wenxi and Gu Chengyan, hereafter the Parties. Preamble: The Parties shall be punctual, courteous, and keep a straight face."

Wenxi had sharpened the pencil three times, which was twice more than a pencil required.

She sat at the kitchen table of Su Ji at ten to eight on Monday evening with the lamp pulled low, a pad of the flour merchant's order forms squared up in front of her, and a pot of Longjing going cold at her elbow. Grandma had left for the Wei sisters' at seven sharp with her mahjong bag, her sunflower seeds, and an air of such pointed innocence that Wenxi had checked the doorframe for listening devices. The back door stood on the latch. The new beam overhead smelled faintly of a forest. She had tidied the table twice. She had set out a plate of almond biscuits and then removed it, because biscuits made it look like a party, and then put it back, because a table without biscuits looked like an interrogation.

At eight o'clock exactly there was a knock.

The door was open. She could see him through the gap. He knocked anyway, three firm raps on the frame, and waited, and she understood that this was going to be that kind of evening.

"It's open," she called.

Chengyan came in sideways, the way he came through all doorways in this house, as if the lintel might have moved since last time. He wore a clean grey shirt buttoned to the second button and the expression of a man arriving at a bank. In one hand he carried a flat red carpenter's pencil. In the other, for reasons she could not begin to guess, he held a folding rule.

"What is that for?" said Wenxi.

"Habit."

"Are you planning to measure the contract?"

"I'm planning to measure nothing." He looked at the rule, and put it in his back pocket with great dignity. "Where do you want me?"

"There. Across from me. Like a negotiation."

"Is it a negotiation?"

"I think," said Wenxi, "it is the most negotiation either of us has ever done."

He sat. He laid the pencil on the table, parallel to the edge. She noticed, with a small unreasonable tenderness, that he had combed his hair with water and that one piece at the back had given up and was standing on end.

"Right," she said. She wrote the title in capital letters across the top of the form. AGREEMENT OF TEMPORARY COOPERATION. She looked at it. "Is that too formal?"

"It's accurate."

"Do we need a preamble?"

"Yes."

"What goes in a preamble?"

"The part," said Chengyan, "where we promise to behave."

She wrote, as he dictated, in her round looping script that sloped uphill the more nervous she got: The Parties shall be punctual, courteous, and keep a straight face. She read it back. He nodded once. It was, she thought, the first line of a very serious document, and her mouth was already trying to curl up at one corner.

"Clause one," she said. "Term. I said until the harvest finale. That's when the prize is decided."

"The festival."

"The Flower Boat Festival is in the middle of summer, Chengyan. The prize isn't awarded until autumn."

"I'm not doing this until autumn."

"Then we might lose in round two."

"We don't lose. We review." He tapped the table once with a blunt finger. "At the festival. If it's going well, we talk about extending. If it isn't, we stop."

"What does going well mean?"

"Not killing each other."

She wrote it down in her best legal hand: Clause 1. Term. This Agreement runs from signing until the close of the Flower Boat Festival. It may be extended by mutual written consent only. She underlined written, because he had looked at the word as if he meant to, and he gave a small grunt of approval that went through her, absurdly, like praise from a teacher.

"Clause two," he said. "Nobody knows."

"Nobody knows what?"

"That it isn't real."

"Oh." She had not thought of that. Then she thought of it, and her stomach dropped a little. "My grandmother."

"Mine, too."

"Your grandfather would..."

"Be very happy," said Chengyan, in a voice with no happiness in it at all. "For about a week. And then he'd find out. And then he'd be sad. And he'd say nothing, and sit in his chair and look at the canal." He stopped. "I'd rather not do that to him."

It was the longest speech he had made to her in a month. She put the pencil down. She understood, abruptly, that the rule was not for the judges, nor for the street. It was for the two old people who had put their whole hope, for years, in the idea of the wall between their houses coming down.

"Nobody," she agreed softly. "Not grandparents. Not cousins."

"Not Zhaoyu."

"Definitely not Zhaoyu. He'd put it in a spreadsheet."

"Not Tang Rui."

"Tang Rui will guess in about ten minutes."

"Then she can guess," said Chengyan. "As long as nobody tells her."

Clause 2. No one is to be told that this arrangement is not real. This includes grandparents, cousins, apprentices, and Tang Rui. She wrote it out in full, and as she reached the end she became conscious of a small, sly feeling that somewhere in the house a floorboard had creaked. She looked up. The passage was dark and empty. Grandma was at the Wei sisters', playing, she hoped, very badly.

"Clause three," said Wenxi, and picked up the pencil with new briskness. "Physical contact. For believability, I think we'd want to hold hands. In public. Quite a lot. Couples do. They hold hands at the market, over the bridge, at the..."

"Once a day."

"Once?"

"Once."

"Chengyan, there are seven hundred people in this street and every one of them has an opinion. They will want to see hands. They will inspect them with magnifying glasses. Five."

"Two."

"Four."

"Two."

"Four, with a rest period."

"Three," said Chengyan, "and not more than five minutes each. Public only."

"What counts as hand-holding?"

He considered it with the gravity of a man asked to define a load-bearing wall. "Palm to palm."

"What about fingers? What about when you, you know, lace them."

His ears went pink. It was the tiniest flush, only at the rim, but she saw it, and her own face responded in kind. "That's two," he said.

"Fingers count as two."

"Fingers count as two."

Clause 3. Hand-holding shall be limited to three (3) occasions per day, in public only, not exceeding five minutes each. Interlaced fingers count as two. She wrote the last sentence without looking up, and felt her face grow hotter with every letter.

"Clause four," said Chengyan. He cleared his throat. "Neither of us goes into the other's house after nine in the evening."

"What, never?"

"No."

"You were on my roof at one in the morning."

"That was structural."

"That was structural," she repeated, delighted. "That is the single best thing you have ever said." She was writing it down, hiding a grin in her shoulder. "Is there an exception for emergencies?"

"No exceptions."

"Not even floods?"

"We live on a canal. Of course there are floods. We've survived them."

"Not even fire?"

"Call the brigade."

"You are impossible," said Wenxi, and wrote, with great satisfaction, No exceptions, and underlined it three times, because there was nothing in the world she enjoyed more than finding the edge of a rule and leaning on it a little, and the thought that one day he would have to explain this line to himself made her so happy she could have hugged the pencil.

* * *

Chengyan watched her write.

He had not meant to. He had meant to look at the lamp, or the biscuits, or the grain of the table, which was beech, wide-planked, old, with a long split down one side that he had glued himself at the age of fourteen. But the lamplight caught the top of her head, and the neat parting in her hair, and the way the tip of her tongue showed at the corner of her mouth when she wrote a word she wanted to get right, and his eyes kept returning to her like a compass needle to the north.

It was extraordinary how well this was going.

He had come in braced for a trap. He had practised on the walk across the courtyard: the cold voice, the list, the short stiff sentences, the whole careful architecture of distance, built like shutters against a storm. And then he had sat down opposite her, and she had said, Is that too formal? with her pencil in the air and her whole face open, and he had heard himself say it's accurate in a voice that did not sound like a wall at all.

Three times already she had made him nearly laugh. He kept count, with the stern part of his mind that counted everything.

The stern part knew exactly what it wanted. It wanted one more clause. It had wanted it since the evening on the bridge, when she had sat there with her hair coming down and her eyes on the water, saying we wouldn't have to pretend very hard, and something under his ribs had gone off like a dropped plank. We wouldn't have to pretend very hard. He had been turning that sentence over for two days like a splinter under the skin.

"Clause five," he said.

She looked up, pencil poised. "Yes?"

His mouth had gone dry. He picked up his own pencil, to have something in his hand, and set it down again. He was aware that his hands on the table were not entirely still. It was the most absurd thing. He had held a chisel steady over an inch-thick mortise in a hailstorm. He had carried his grandfather down fourteen stairs the winter the old man had flu. His hands had never in their lives shaken at a kitchen table.

"No real feelings," said Chengyan.

The words fell between them like two plates.

She did not move. In the lamplight her face was perfectly still, and then it was smiling, brightly, as if somebody had pressed a switch.

"Of course," said Wenxi.

"It should be a clause. So that nobody gets, so that it's clear."

"Obviously. It's the most important one." She was writing already, in quick sharp strokes, her handwriting suddenly neat and upright instead of looping. No real feelings, she wrote, and then, because that was apparently not enough, Clause 5. No real feelings shall be developed, expressed, or acted upon by either Party. She underlined it. She underlined it again. "Done. Anything else? I think that's the main thing, honestly. Perfectly sensible. Very wise of you."

He stared at her.

It was exactly what he had wanted. It was precisely what he had braced for. She had accepted at once, with no hesitation, not a second's pause for thought, as though he had asked her to confirm the time of the bus. It was the neatest possible outcome. It was the one he had come to get.

And something in his chest went tight and sour as a bitten plum.

"That was quick," he said.

"Was it?"

"You didn't want to discuss it."

"What is there to discuss?" She was smiling at the paper. "We're two sensible adults. It's a business arrangement. We don't want it to get complicated. Obviously there won't be any feelings. We can hardly stand each other."

"We can't?"

"You said it yourself. Twenty minutes at a time."

"I didn't say that. You said that."

"Well, I'm saying it for both of us." She put the pencil down and rubbed her wrist. "Honestly, Chengyan, it's a relief. It's so much easier when everyone knows where they stand."

He nodded slowly. He looked at the line she had written, the heavy double underscore, the neat black words, and a thin hot irritation crept up the back of his neck that had no business there. He had asked for it. She had given it to him, quickly and with a smile. A man could not be angry at a person for agreeing with him.

He was, though. He sat there in the lamplight, absurdly, painfully, furiously irritated, and the stern part of him said with great clarity: you proposed the clause. You wrote the bars of your own cage. And the other part of him, the part that had laughed on a roof, said nothing at all.

"Clause six," said Wenxi, brightly. "The one we'd all rather skip."

"Which one is that?"

"Kissing."

The word dropped into the kitchen like a glass off a shelf.

He did not look at her. He looked at the biscuits. "There's no need for kissing."

"There might be. If the judges asked us to, at the festival. Or someone shouted kiss, kiss, and everyone started clapping. It happens at weddings. It could happen at a boat race." She was talking faster, and her cheeks were going from pale to pink to a deep determined red. "I'm only saying, if it were absolutely necessary. For the performance. We'd have to be prepared."

"Prepared."

"Not practised. Obviously not practised. I mean we'd have a procedure."

"A procedure."

"Stop repeating me."

"I'm trying to understand the clause."

"The clause," said Wenxi, with her ears now crimson and her eyes locked on the paper, "is that kissing is permitted only where strictly required for the performance, with prior notice of not less than one hour."

"An hour."

"So that nobody is ambushed."

"And where?" He did not know why he asked. It was out of his mouth before he could stop it. "Where would it be, if it were required."

There was a terrible silence.

"Cheek," said Wenxi, in a very small voice.

"Cheek."

"It's a very respectable place."

"Forehead," said Chengyan, a little hoarsely, "is more respectable."

"Forehead." She wrote it down. Her hand was not quite steady. Clause 6. Kissing is permitted only where strictly required for the performance, with not less than one hour's notice, and then on the cheek or forehead only. She read it back to herself in a murmur, and then laid both hands flat on the table, and breathed in, and out.

They sat there. The clock ticked. The ginger cat from next door had come to the window and was looking in at the two of them with its head on one side, the way a person looks at an interesting accident.

"This is the worst clause," said Wenxi, to the table.

"Yes."

"Can we agree that nobody mentions it again?"

"Agreed," said Chengyan, with feeling.

She drew a long breath, and he saw her square her shoulders as if she had come to the edge of a cliff. When she spoke again her voice had gone light and flat and entirely careful.

"There's one more. I'd like one more, if you don't mind."

"Go on."

"We don't talk about the past." She was not looking at him. She turned the pencil over, end to end, between two fingers. "The eight years. What I did, the night I went. I know you've never asked, and I'm grateful that you haven't. But I'd like it to be, for the length of this, a thing that doesn't come up. Nobody asks. Nobody explains."

"I wasn't going to ask," said Chengyan.

He said it quite gently. He meant it kindly. It was true. He had told himself for eight years that he had no right to ask, that a person who has been left does not get to demand the reasons, that the questions were hers to give or to keep.

He saw her flinch.

It was so slight that nobody else would have noticed. Her eyelids flickered. Her hand tightened round the pencil. She said, brightly, "No. Of course. That's what I thought," and wrote Clause 7. The Parties shall not raise or inquire into the events of the preceding eight years, and her pencil moved across the page as steadily as if nothing had happened.

He did not understand it. He had given her what she asked for. He had said the right thing. And yet the whole warm kitchen seemed to cool by a degree, and he sat with his hands on the table knowing that he had missed something he could not name, and that the missing of it would cost him.

* * *

They signed at nine.

It had taken Wenxi an hour to produce a clean copy, because she insisted on a fair copy, and half an hour for him to read it, because he insisted on reading every word. He had found two spelling errors. She had found one, which he had made when he initialled the margin. There had been a brief and dignified quarrel about whether a contract could be valid if written on flour order forms, which ended when he turned the page over and pointed out that the front said, in large print, Qiu and Sons Mill, Reliable Since 1952, and that if it was good enough for flour it was good enough for this.

She had gone to the dresser and fetched, from the back of the left-hand drawer, her grandfather's old fountain pen. It was a heavy black thing with a gold nib, and it had not been uncapped since before she left. The ink had dried to a crust. She had soaked it in a saucer of warm water and cleaned it with a twist of cloth, and when she made the first stroke on a spare form it came out thin and pale, then dark and sure, and she felt a small unexpected catch in her chest. Grandfather had signed every ledger in this house with that pen.

Now she dated the document and wrote her name, Su Wenxi, in the bottom corner, with a small flourish on the last letter. She set the pen down. She turned the paper round to face him.

Chengyan took up the pen. He held it as he held a chisel, in the whole fist, and for a moment she thought he would sign the way he did everything, slowly and with great weight. Then he bent his head and wrote Gu Chengyan in square upright strokes, each letter a plank laid flat.

He capped the pen and set it down.

"That's it," said Wenxi.

"That's it."

It felt strange. She had expected a ceremony. She had expected something to change in the air of the room, a bell, a tremor, but there was only the lamp and the cooling tea and the ginger cat on the sill, and a long page of ink drying. A whole summer of her life, she thought, signed over in one evening, on the back of a flour order, for a roof.

"Should we shake?" she said.

"People do."

She held out her hand across the table. He looked at it for a moment, as if it were a joint he had to check before he could trust it. Then he reached out and took it.

His palm was big and dry and warm, hard along the pads of the fingers, and it closed round hers with a slow, careful pressure, like a man lifting something that might break. She had held his hand ten thousand times. She had held it crossing roads, climbing walls, in the dark of the flood nights, in the hot bright middles of summers. She had thought she remembered what it was like.

She had not remembered anything.

For one long second neither of them moved. His thumb lay along the edge of her hand, very still. She could feel her own pulse beating against his skin, quick and ridiculous. The clock had stopped ticking, or she could no longer hear it. Across the table his eyes were on their joined hands, and in the lamplight she saw the line of his throat move as he swallowed.

"Your hands are warm," said Chengyan, abruptly.

"So are yours."

"It's the tea."

"It's absolutely the tea."

He let go. She took her hand back and tucked it into her lap and held it there with the other, as if it were a bird that had flown in at the window. He cleared his throat, and stood, and took up his pencil, and looked briefly at his folding rule and left it in his pocket.

"Tomorrow," he said, "we take it to Tang Rui."

"Tomorrow."

"Eleven o'clock."

"I'll be punctual," said Wenxi.

"And courteous."

"And I'll keep a straight face."

The corner of his mouth moved. He turned and went out through the back door, and she heard his boots cross the courtyard, and for a long time after she had stopped hearing them she sat at the table with her hands in her lap, listening to her own heart go on, quite stupidly, as if it had been told something.

The application went in at eleven the next morning, in a cream envelope, with two photographs and one form. They had agreed that the contract itself would not be submitted. It was private. It was between the Parties. The official form was a single page headed COUPLE OF THE OLD STREET: ENTRY, with boxes for names and ages and a long ruled space at the bottom, under the instruction Please tell us in a few lines how your story began.

Wenxi had written, in tidy capitals: Childhood neighbours. Lost touch. Found again.

Chengyan, reading it over her shoulder, had said, "That's true."

"I know," she said. "That's what makes it safe."

Tang Rui took the envelope across the counter of the tea house with both hands. She was wearing a green silk jacket, a pencil through her fringe, and an expression of such scrupulous neutrality that it could have been displayed in a museum. She opened it. She read the form. She read the names. She turned it over, as though the back might say something, and then she looked up, slowly, at Wenxi, and then at Chengyan, and at the careful two feet of air that stood between them.

"Well," said Tang Rui.

"It's a perfectly ordinary entry," said Wenxi.

"Isn't it."

"We'd like a receipt."

"I'll write you a receipt." She took a small pad from under the counter, tore off a slip, and began to write in her small, slanting, mischievous hand. She wrote slowly. She wrote with her tongue between her teeth. When she handed it across, Wenxi saw that it said, in full, Received, one entry, Su and Gu, from a couple, and below it, in a tiny unmistakable flourish, a heart.

"Tang Rui!"

"I don't know what you mean."

"That is not a legal receipt."

"It's the one we have." Tang Rui smiled, perfectly serene, and leaned over to tuck the envelope into a box labelled ENTRIES, which already held, Wenxi noticed with a pang, nineteen others. She lowered her voice. She said, in a tone of the purest friendly concern, "I'm so pleased for you both. You look so natural together."

And she winked.

It was a very slow wink. It travelled the whole width of her face. Beside her, Wenxi felt Chengyan go as rigid as a plank, and heard him say, in a voice of great and unconvincing calm, "Thank you for your time."

"Oh, any time," said Tang Rui. "Any time at all. I'll be seeing you. I imagine," she added, with a lingering look at the two feet of air, "very often."

They fled. They were out on the bridge before either of them spoke, with the willow stirring above them and the whole bright spring morning pouring down. Wenxi, clutching the little paper slip with its heart, realised that she was laughing, and that he was not, and that his ears, again, were red.

"She knows," said Chengyan.

"She doesn't know."

"She knows."

"She suspects," said Wenxi. "It's different. It's in Clause Two."

"What is?"

"That she's allowed to guess." She tucked the receipt with great care into the pocket of her cardigan, beside a folded strip of red paper that she had not meant to bring. "We're not to tell her. We never said she couldn't wink."