There was a man called Walter who was born out of a tank. It shouldn't have been so unusual, after all, when Pyrite was settled everyone had been born out a tank -- they only sent enough people from Earth to run the equipment and get all the babies started and bring them up. They kept right on running those tanks, too, until there were enough grown up people to have babies of their own, people to populate Pyrite City and Great Canyon and Simbardo and clear out to Fool's Gold, people enough to be talking about building cities off on the other side of the Bumpy Mountains.

By the time Walter was born they were only running the tanks if the children of the children of the first tank children didn't have enough children. There would be numbers in the news on Landing Day every year, how many babies had been born, and if it wasn't enough, how many tank babies would be born to make up. So having tank babies meant people weren't doing as much as they could, and that meant that tank babies were bad, and pretty soon the whole idea of tank babies got to be embarrassing and not to be mentioned around nice people.

Walter grew up well enough in the orphanage, and qualified as an engineer. When he was twenty-four he met and married a nice girl called Maud, who was prepared to overlook his shortcomings of background because she loved him. His shortcomings weren't very obvious as shortcomings, to tell the truth. In fact he was so good looking and smart and hardworking that when he told people he was tank born they just didn't know what to say. Maud didn't like him to tell people, though. It made her uncomfortable.

The only way his background made him really unusual was that he didn't have any family. Everyone on Pyrite had more brothers and sisters and cousins and uncles and aunts and grandmothers and grandfathers than they could really keep track of. Walter didn't have anyone, except once he'd got married he had Maud's relations, who accepted him into the connection fairly graciously, considering. Now Maud was a Delgarno, or at least her mother was, and her father was a Li, and you'd think that would be enough relations for anyone, and that's what Maud told her daughter Arabetsy when she was getting old enough to be asking questions.

Walter's lack of family made him surprisingly fond of Maud's family traditions. He especially loved all the holidays when they'd get together in each other's houses and eat. One year it was their turn to host the Landing Day dinner for the whole clan. Walter was helping Maud cook in advance, and she asked him to cut the end off the ham for her.

"How much should I cut off?" he asked.

Maud hesitated, and Walter wondered if this was something that everyone knew except tank kids. "Oh, about ten centimetres, honey," she replied.

He cut the end off in a jiffy with his monofilament saw, and as he gave the ham to his wife he asked, "Why do you do that?"

"What?" she asked, busily sticking silverburrs on sticks.

"Why do you cut the end off that way? It's good meat, it seems to me."

"Oh honey, it's just a thing you have to do with ham. I don't know why. I do it because that's what my mother showed me how to do. Maybe you ought to ask her."

At that moment, Cleo, Maud's mother, who lived in Fools Gold and had come early for the party, came into the kitchen looking for a drink. "Do you know why you cut the end off ham?" Walter asked her.

Cleo poured herself a drink and looked down her nose at Walter. "Did you never see anyone do that before?" she asked. "Well, I suppose it isn't surprising. I don't know exactly what it's for, but that's the way my mother taught me how to do it."

The next day as they were eating their dinner, Walter remembered about the ham. He was feeling quite stubborn about it by now. He was an engineer, and it didn't make sense to him. He wasn't ashamed of having no family, and he refused to feel that way. He went up to his grandmother-in-law, Alyssanne, who had never quite approved of him, and he asked about the ham. At first she tried to put him off, but at last she admitted that she didn't know the purpose of it either. "My mother used to cut the end off, so I do it."

Now Britney, Maud's great-grandmother, wasn't at the Landing Day party. She was old and sick, on the end of her life-extension treatments, and she lived in a retirement community over at Johnson Bay. The next time Maud and Walter took the kids over to see her, Walter was glad to have something to talk to her about as she sat in her rocker staring out across the aubergine waves.

"There's something I was wondering," he said.

Britney turned her head to look at him. She was so old that she had almost no hair and her eyes were hard to see in all the wrinkles. She still had a lovely smile. "What's that, Walter?" she asked.

"When you cook a whole ham, for the Landing Day party, why do you cut the end off before cooking it? Maud said she did it because Cleo did, and Cleo said she did it because Alyssanne did, and Alyssanne said she did it because you did. I know I'm a tank kid and don't have any family traditions of my own, so I'm kind of interested in Maud's, and this seems strange because it's good meat and it doesn't make sense."

Britney rocked a moment, and then she said, "You know, I'm glad you asked me that question. I was born from a tank myself, and my whole generation, as you know. The thing is, when the ship first landed we only had what we'd brought from Earth, before we got the Mufug Plant set up, and even then, it could only make certain things, not like today. So when I was growing up, in the orphanage, and when I was first married we didn't have any dishes big enough to take a whole ham, so we used to cut the end off to fit in the dish."

And Walter laughed, and Britney smiled her sweet smile, and Maud laughed, and Arabetsy, who was the only one of the children old enough to understand, laughed until she almost fell off the balcony into the sea.

Jo Walton is the author of four fantasy novels: The King's Peace; The King's Name; The Prize in the Game; and the World Fantasy Award winning Tooth and Claw.  Her latest novel is the Nebula nominated Farthing. The sequel, Ha'Penny, will be out from Tor in October 2007.  She comes from Wales but lives in Montreal where the food and books are more varied. Her exciting online journal, with word counts and occasional actual content, is here.