Daikansho was the administrative heart of the Iwami Ginzan silver mine, the place where the magistrate sent by the shogun ruled the district. After the Tokugawa took over the mine in 1600, they appointed a daikan, a magistrate, to oversee production, collect the silver and govern the people, and the office, in the town of Omori, became the centre of power in the valley. The surviving gate and the long white-walled building that now houses a museum were rebuilt in the nineteenth century, and they give a sense of the weight of officialdom in this remote place.
The first magistrate is the most famous. Okubo Nagayasu, a man of unusual talent who started his career as a Noh performer's son and rose to become a mining engineer, was appointed to Iwami and later to Sado Island, another great source of silver. He reorganised the workings, improved drainage and ventilation, and stabilised the district, and he is remembered as the man who made the mine efficient. The silver was carried by pack horse over roads to the coast and then shipped to the capital, and some was exported through Hakata and Nagasaki.
For motorcyclists, the approach is simple. The valley road from Oda leads in along the river, with a single lane in places and a few passing bays. Visitors are encouraged to park in the lots at the edge of the old town and walk the long street, which is lined with wooden houses, temples and shops, and a small shop selling local sweets and stone-ground flour is a good stop. The surface is generally good, but it is narrow and shaded, and leaves can be slick in autumn.
Fuel is in Oda, eleven kilometres away, and there is little in the valley itself. Rain is frequent here, so a waterproof layer is wise in any month. If you want to see more of the district, rent a bicycle in the village, since the best way to feel the scale of the old town is slowly. Come early in the morning, before the tour groups, and the street is empty and quiet.