The hammer rang once. A spark jumped off the anvil and did not go out. It waited. They followed.

The spark led them to the bench under the big tree on the Green. Then it simply waited there.

Warm wind blew the Green away, and the ground under their feet was somewhere else, the day before.

They were standing on a grassy hill above a fast, clear river. Yellow leaves were falling from the birch trees. Low hills rose on the far side. It was cold, and a thin new moon hung in the pale sky.

There was a small camp on the hill, with shelters made of poles and animal skins, and a fire. People were scraping skins and stacking wood. On a skin bag by the fire, beside an old mended tear, somebody had scratched a tiny hammer.

A girl their age was sitting by the fire, looking at the moon.

"My uncle is going away tomorrow," she said, when she saw them. "He hunts in the far hills all winter. He always keeps the count of the seasons. Now it is my job."

"The count of what?" asked Lan.

"Of when the salmon come back," said the girl. "In the spring they swim up the river to the falls. If we are there on the right day, we eat well all year. If we are late, they are gone."

Inkling knew what the girl needed. She had one on the kitchen wall at home, with pictures of cats on it.

"I noticed it straight away," said Inkling. "What you need is called a..."

She said the word before she had looked.

Bzzz.

Inkling went pink. Lan squeezed her hand.

"The door," said Lan kindly. "Only the question."

"How will you know when to go?" asked Lan.

"When it feels warm," said the girl.

Her uncle shook his head. "Last year a warm week came in the middle of winter," he said. "People went down to the falls early. The river was empty, and frozen at the edges."

The girl found a long cord. "I'll tie a knot every day," she said. "One knot, one day."

She tied a knot for today, and one for yesterday, and one for the day before.

But a winter was long. It would be about thirty knots for each moon, and six moons or more until the salmon. That was a hundred and eighty knots. By the end, the cord would be a tangle, and nobody could tell how many knots it had.

Inkling did not name anything this time. She asked questions instead.

"I noticed something," said Inkling. "What comes round again, all by itself?"

The girl looked up. "The moon," she said. "It's thin, then round, then thin, then gone. Then thin again."

"How many moons until the salmon?"

"Six or seven," said her uncle.

"Wait, I can name it," said Inkling. "Count the thing that comes round again. Count moons, not days. Moons are bigger to count."

It got dark and cold. The girl looked at the thin moon.

"By the spring I'll have lost count," she said. "We'll miss the salmon. Everyone will be hungry."

Lan looked at the flat grass by the fire.

"Could each moon have a place in the ground?" said Lan. "A place that stays, so anyone can read it?"

The girl's uncle gave her a digging stick. She dug a row of shallow pits in the grass, one for each moon of the year. They counted them together, touching each one. Twelve.

She put a smooth river stone in the first pit. "This is this moon," she said. "When the next thin moon comes, the stone moves one pit along."

"Twelve moons are a bit short of a whole year," said her uncle. "If you only count moons, the count slips."

Twelve moons were about three hundred and fifty-four days. A year was about eleven days longer.

"Can I ask one more thing?" said Lan. "Where does the sun come up on the shortest day of winter?"

The uncle pointed. "In that dip in the far hills."

So they turned the row of pits to point at the dip. On the morning the sun came up in the dip, the stone would go back to the first pit, and the count would start again on the right day, every year.

All winter the girl moved the stone at every new moon. On the shortest day, the sun came up in the dip, and she put the stone back at the start.

In the spring she looked at the pits, and the stone, and the moon.

"Now," she said. "It's time."

The family went down to the falls. The river was full of silver salmon, jumping up the white water. And there was her uncle, coming down from the hills to meet them.

Nobody would write down the girl's name, or her uncle's.

Warm wind blew the day before away, and the grass under their feet was the Green.

On the side of the anvil, under the word DOOR, after the O and the P, there was a new letter. An E.

"O, P, E," said Inkling. "One more."

The spark dimmed to a warm dot and settled back on the anvil. The Green was just the Green again.

Back on the Green

Lan drew a row of boxes on the fridge, one for each day until her birthday, and moved a button along one every morning.

Tell the story back to someone. Why did counting moons work better than counting days? Why did they point the pits at the dip in the hills?