The valley is quiet.

For the last two kilometers, from the gate to the dam, nothing with an engine is allowed through — no cars, no motorbikes, not even bicycles. The rule has held since 1976, when the operators put electric vehicles on the road instead. The current buses are the third generation, five of them, and they run all day along a road that has not heard a combustion engine in almost fifty years.

Which means that at the height of the foliage, when the cliffs above the reservoir turn over into red and orange, you hear water and very little else. It is a strange quality for a place this popular to have.

Sit on the left going up, for the Kudan Falls. Sit on the left coming back too, and you get Senjo Rock instead — the same road returning a different view. You can also walk it, through two tunnels, in about half an hour.

The color starts on the cliffs in early October. Below it the dam is letting water go: the scheduled releases run until the end of the month, so for a few weeks the falling water and the turning leaves are there together. Not long after that, the snow closes the road for the winter.

Sapporo is an hour away by car, which is the part people find hardest to believe. All of this is still inside the city.