Two pairs of tall brick chimneys stand in a quiet suburb at the base of the Izu Peninsula, looking strangely European against the green hills. They belong to the Nirayama reverberatory furnace, built in the 1850s to melt iron for casting cannons, at a time when Japan felt threatened by Western warships arriving in its waters. The project was led by Egawa Hidetatsu, the local magistrate, a forward-thinking official who studied Western military technology from Dutch books. He died before it was completed, and his son finished the work. It is the only surviving reverberatory furnace of its era in Japan that was actually used for casting, and since 2015 it has been part of the UNESCO site of the Sites of Japan's Meiji Industrial Revolution.
The furnaces are made of firebrick, with a structure of stone and iron to hold them together, and they have been restored. A small visitor centre explains how they worked and the story of the Egawa family. There is also a tea plantation on the hillside behind, where you can taste local green tea while looking at the chimneys.
The Izu Peninsula is one of the most popular riding areas near Tokyo, and with good reason. The Izu Skyline, a toll road along the spine of the mountains, offers flowing bends and views of Mount Fuji and Sagami Bay. The west coast road, Route 136, winds along cliffs and coves, with views of Fuji across Suruga Bay on clear days. Inland, the old Amagi pass road climbs through forest past waterfalls, and the Kawazu Nanadaru loop bridge, a double spiral of road, is a highlight on the descent towards the east coast. Traffic can be heavy at weekends and holidays, especially in spring and summer.
The peninsula is famous for its hot springs. Shuzenji, a short ride south of Nirayama, is a charming onsen town with a temple, a bamboo forest and a river running through the centre. Soaking in a hot spring after a day of riding is one of the great pleasures of touring in Japan.
Izunokuni and nearby Mishima and Numazu have fuel, supermarkets and restaurants. Numazu is known for its fresh seafood, especially horse mackerel. The weather is mild compared with Tokyo, but rain is frequent in early summer, and typhoons can bring heavy storms in late summer and autumn.