Getting there takes about six hours on foot, and there is no other way. From Kamikochi the trail follows the Azusa River upstream to Yokoo, then an hour on to the Hontani bridge, then two hours of climbing to the Karasawa cirque at 2,300 metres—a bowl scooped out by an ice age glacier and closed on three sides by the rock walls of the Hotaka range.

The colour is rowan, and it fills the slope beneath the cliffs so completely that the grey of the rock reads as the frame rather than the subject. The Kamikochi authority gives mid-September for the first turning and late September to early October for the peak.

Karasawa sits inside Chubu-Sangaku National Park, below Okuhotaka, the third-highest point in Japan.

At the height of the season the campground fills with several hundred to a thousand tents, and the photographs everyone knows are as much about that—coloured nylon spread across the floor of the cirque—as about the trees. It is worth being clear that this is not a place you can drop into. There is no day trip. You sleep at the hut or in a tent, you carry what that requires, and you make a real judgement about the weather before you start walking. If you can do those things, go at the end of September.