This road was not built to be looked at. It was built to be driven along, by members of the imperial family inspecting a stock farm that the Imperial Household Ministry kept here. The planting came afterwards, between 1916 and 1919, when Ezo mountain cherries and other trees were dug up in the hills nearby and moved down to line both verges.

The result is very simple and very long. Seven kilometres, dead straight, with the carriageway held at exactly twenty ken, which is about thirty-six metres. Twenty ken is what the road is called: Nijukken-doro. The name is a measurement rather than a description, and that is fair warning about the place.

More than two thousand cherry trees stand along it now. The official Hokkaido tourism guide puts the flowering in the first half of May, running into the middle of the month. That is late enough that most of Honshu has finished. In the first week the road fills with cars moving at walking pace.

Almost nobody walks the whole seven kilometres. You go a little way in, and then you turn round. What you see when you turn is the point where the two lines of trees appear to meet, still a long way off, with more road behind it. It is the sort of view that tells you how long a straight line actually is.