Few people riding beside Lake Okutama realise that they are looking at the roof of a drowned valley. The lake exists because of the Ogouchi dam, built across the Tama river in the 1950s to give Tokyo more drinking water, and when the gates closed, the rising water covered farms, a shrine and a handful of villages. Several hundred households were moved to higher ground, and old photographs show the fields and houses that vanished. It is a quiet piece of postwar history, and it explains the unusual stillness of the place.
The shoreline is irregular, with many arms and inlets where the original side valleys flooded, and the road runs high above the water through tunnels and across bridges, with views opening between cedar trunks. The water has a deep green-blue colour that changes with the weather, and on calm mornings the mountains reflect so exactly that the lake becomes a mirror. Walking paths lead along the shore, and a floating footbridge across one of the inlets, swaying gently underfoot, is a favourite stop for visitors.
The mountains around are the Okutama range, forested with cedar and cypress, and with beech and oak higher up, and they are home to deer, monkeys, boar and a few Asiatic black bears. The most dramatic part of the year is autumn, when the slopes burn red and gold, and the weeks around early November draw crowds. Spring brings fresh green and cherry blossom, and in winter, snow often dusts the upper slopes and ice forms in the shaded corners of the road.
This is remote country. Otsuki and Itsukaichi, the nearest larger towns, are about twenty kilometres away, and the lake has only small facilities: a few shops, restaurants and vending machines, with limited hours. Fuel is scarce, so fill up before you leave the plain, and bring a spare layer, since the air is chilly even in summer. The best riding is during the week, when traffic is light, and the best time of day is early, when mist hangs on the water and silence fills the valley. On a damp afternoon, the lake has an almost Scottish mood, with cloud low on the ridges and the smell of wet cedar.