Kurumayama is a smooth, grassy mountain on the Kirigamine plateau in central Nagano, at nearly two thousand metres, and it stands above one of the loveliest high-altitude roads in Japan. The plateau is a broad volcanic upland, a pale green tilted table of grass and wildflowers lifted high above the lakes and valleys, and the road that crosses it, known as the Venus Line, was built to show it off. On a clear day the view from the top is huge: the Northern Alps to the west, the Yatsugatake range to the south, and, if you are lucky, the distant cone of Mount Fuji.
The mountain is part of a high plateau whose name, Kirigamine, means the peak of mist, and the name is earned. Fog rolls across the grass with little warning and wipes out the view, then lifts and reveals the lot. The meadows here are famous for their flowers in summer, and the grazing cattle, the open skies and the cool air make a fine contrast to the heat of the lowlands. In winter the hills are covered in snow, and sections of the road close from late autumn through spring, so check before you set out.
For a rider, the Venus Line is a gem. It is a smooth, well-kept scenic road with wide, flowing bends, long straights and sweeping views over the plateau, and almost no commercial traffic. Speed limits are low and strictly watched, as they are across Japan, but the real pleasure here is the pace: gliding across open grassland at an easy speed with the mountains in the background. It is popular with riders at weekends and in autumn, and there are often groups of motorcyclists stopping at the roadside car parks. Early mornings and weekdays are quieter.
The area has a small number of mountain restaurants and shops near the viewpoints, and the local food is simple: soba noodles, a speciality of Nagano, served hot or cold, with mountain vegetables and tempura. Japanese stations are generally full service, and the attendants will guide you to the pump.
Bring a light jacket even in summer, since the air at this height can be cold when the sun goes in. The best seasons are early summer, for the flowers, and October, when the grass turns to gold and the larches on the lower slopes are bright yellow.