December colour is rare in the Kanto region, and Yoro Valley is where it happens. The Boso peninsula holds its warmth late into the year, so the peak arrives correspondingly late — the end of November into the first days of December, after most of the region has finished.

The valley is cut by the Yoro river, running north from Otaki toward Ichihara, and it is not one viewpoint but four: Awamata Falls, the Nakase walking path, Kaisho Kogen, and the maple valley at Tsutsumori, spread along the river rather than clustered. Awamata is the one most people come for, and it is not a vertical drop. The water falls thirty metres but slides a hundred metres of rock doing it, wide and shallow, a broad white sheet laid under the colour.

The path in runs at river level, so you look up at the trees instead of down on them. Maple grows alongside lacquer, sawtooth oak and konara here, and the mixture of species keeps the colour mixed too — not one red but a range of them, with rust and gold between.

In the season the lights come on from five until nine in the evening, and in December that means the lighting begins before the daylight has quite gone. The four sites are a drive apart, not a walk. Take the whole afternoon. This is the autumn that waits for you; it deserves the same courtesy back.