Nirayama Reverberatory Furnace

Four brick chimneys about 15.7 m high, braced with a steel lattice, stand in a field on the edge of Izunokuni. Under them are two pairs of furnaces set at right angles so molten metal ran to one point for casting. The shogunate ordered the works after Perry's ships came in 1853, to make iron cannons for the batteries guarding Edo Bay. The local magistrate, Egawa Hidetatsu, a scholar of Dutch learning, designed it. Building started in 1854 at Shimoda, but after sailors from Perry's fleet walked onto the site that year the work moved inland to Nirayama. Egawa died in 1855 and his son Hidetoshi finished the furnace in 1857, bringing in 11 engineers from the Saga domain, which had built reverberatory furnaces of its own, to complete the north pair. Iron and bronze cannons were cast here from 1857 until 1864.

Most of the reverberatory furnaces Japan built in the 1850s from Dutch manuals are gone. The Agency for Cultural Affairs calls Nirayama the most completely preserved one left in Japan, and it is one of the 23 parts of the Sites of Japan's Meiji Industrial Revolution, inscribed in July 2015. The steel bracing is not original; it went on during preservation work in 1957 to keep the chimneys up in an earthquake.

Start at the guidance centre, where exhibits explain how the furnace worked, then walk round the structure. You can book a volunteer guide for free, and advance booking is recommended. Forty-five minutes to an hour covers it. Honestly, it is one structure in a field, and if you are not interested in how cannons were made, the photos may be enough. What lifts the visit is the tea plantation next door run by Kuraya Narusawa, a shop with a craft beer restaurant. From the viewing platform in its tea field, on a clear day, you see the chimneys with Mount Fuji behind them. A joint ticket also covers the Egawa family's old house in Nirayama.