Nirayama Reverberatory Furnace

Two chimneys supported by iron frames rise side by side against the sky. The Nirayama Reverberatory Furnace in Izunokuni was built at the end of the Edo period to cast cannon, and is known as a facility that conveys the appearance of a late-Edo reverberatory furnace. In 2015 it was inscribed as a component of the World Heritage "Sites of Japan's Meiji Industrial Revolution: Iron and Steel, Shipbuilding and Coal Mining."

A reverberatory furnace melts metal by reflecting heat from its ceiling and walls. The idea of building one came from Egawa Hidetatsu, the magistrate of Nirayama. In 1840, alarmed by the Opium War, he proposed building a reverberatory furnace to cast guns. After the arrival of the Black Ships in 1853, construction was decided as a shogunate-run project and began first at Shimoda, but the next year sailors from Perry's fleet, which had entered Shimoda, wandered onto the site, so the work was moved to its present place at Narutaki in Nakamura. For that reason it was then called the "Nakamura Reverberatory Furnace."

Hidetatsu died in 1855 and his son Egawa Hidetoshi took over. The furnace was completed in 1857. Hidetoshi invited engineers who had worked on reverberatory furnaces in the Saga domain for technical help. The furnace consists of two twin units with four furnaces in all, and stands about 15.6 to 15.7 m tall. The outside is laid in Izu stone (a greenish tuff), and the inside is arched firebrick made from earth of Mt. Amagi in Izu.

Casting was carried out in this furnace from 1857 to 1864. Four cast-iron 18-pounder guns were made, and two of them are said to have been test-fired. On display in the grounds are bronze mortars and a replica of a 24-pounder cannon made in 1998. After the furnace closed in 1864 it became privately run by the Egawa family, and in 1908 local volunteers bought the site and donated it to the Army Ministry. It was designated a national historic site in 1922, and in conservation work in 1957 the iron frames that support the chimneys were added.

Visits begin at the Nirayama Reverberatory Furnace Guidance Center beside the furnace (opened in 2016). The layout requires you to pass through the center to reach the furnace, and it explains, for example, how the Nirayama Furukawa stream was reshaped to bring water for a waterwheel that powered the boring of gun barrels. The World Heritage area includes about 144 m of this reshaped section of the stream. In 2020, remains of the "shachi-dai" platform for moving molds in and out and of a mold-drying hut were also found.

A free guide lasts about 20 minutes; reception is from 9:00 to 16:00, and guides in English are available. The site is closed on the third Wednesday of each month (the next day if it is a holiday) and at the New Year. Allow about an hour in total for the guide and exhibits.

It is about a 20-minute walk (about 5 minutes by taxi) from Izu-Nagaoka Station on the Izuhakone Railway Sunzu Line. Shuzenji Onsen (about 8 km) and the Numazu Port Deep Sea Aquarium and Numazu Port (about 11 km) are nearby, so it also fits into a day trip combining Izu hot springs and the Numazu waterfront.