At the high end of the Izu Skyline, with Atami five kilometres away and the Tanna basin tucked in the valley to the west, the road runs along a grassy ridge where the wind is a constant companion. Gusts can be strong enough to push a bike sideways, particularly at the exposed corners, so keep a firm grip and reduce speed when the grass starts to bend. On the ridge the air is cool and clean, and even in July the temperature can be ten degrees below that on the coast.
The Izu Skyline links the Atami Pass with the Amagi mountains to the south, and the high section is a place of long views. To the west, across the Tanna basin, a quiet farming district with dairy cattle and green fields, the white peak of Fuji sometimes appears, and to the east the Pacific lies spread out like a sheet of metal. In the evening, the lights of Atami and the coast glow below, and the sky turns deep violet.
The Tanna basin is worth knowing about. It is a bowl of farmland pocketed in the hills, home to a well-known dairy industry whose milk and ice cream you can try in the small shops around the area. Beneath it, a long railway tunnel, dug in the early twentieth century with great loss of life, carries the Tokaido line toward Numazu and was one of the hardest tunnelling projects in Japanese history. It is a reminder of how steep and difficult the geology of this region is.
Practically, there are no services on the ridge, and fuel must be bought in Atami or Mishima before you start. Atami has forty thousand people, and Mishima over a hundred thousand, with stations all over. Pack water and a snack. The road is a toll road, and the toll is paid at a booth, so keep coins ready. Quite a few cyclists and other motorbikes use it, and on a fine weekend the car parks at the viewpoints fill up with sightseers. The best time to ride is on a weekday morning, when the road is quiet and the light is crisp, and the best season is autumn, when the pampas grass is silver and the air clear.