Two periods of building stand in the same row. Unno-juku is a post town with a water channel running down the middle of the highway, townhouses along both sides of it, and the sound of moving water coming from the centre of the street rather than the edge. The lattices date from the years when this was an inn town; the udatsu firewalls and the small ventilation windows on the roofs date from the years when it raised silkworms. They are mixed along the same frontage, which tells you the town changed by addition rather than by demolition.

A ventilation window is a small opening built up on the roof to let heat and damp out of a first floor full of silkworms. A post town had no use for one. Unno was designated an Important Preservation District in April 1987; Ueda is twenty minutes away by car, and the Shinkansen puts Tokyo about ninety minutes off. When the highway stopped carrying traffic, the street gave up lodging and took up sericulture; when sericulture ended, it became a residential street for people who commute.

Three uses in succession, and on each occasion the buildings themselves were kept rather than cleared and replaced. A townhouse with a wide frontage turns out to be an adaptable object: fewer travellers, so raise silkworms upstairs; no more silkworms, so live in it. Each use was able to receive what the previous one left behind, which is not true of buildings put up for a single purpose. The lattice still sitting below the firewall is the visible seam of one of those handovers, left in place because there was never a reason urgent enough to remove it.