Kosaka Family Residence Main House

What Is the Kosaka Family Residence Main House?

The Kosaka Family Residence Main House (小坂家住宅主屋, Kosaka-ke Jūtaku Shuoku) is a thatched farmhouse built in the late Edo period (1830 to 1868) in the Murayama district of Nagano City, Nagano Prefecture, and was registered as a Registered Tangible Cultural Property on December 5, 2019.

It stands near the middle of the Kosaka homestead on the left bank of the Chikuma River, facing south. The single-story timber house covers 226 m². The other seven registered structures of the property sit at its corners and along its edges, so the Kosaka Family Residence Main House is the anchor around which the whole compound is arranged.

Why It Was Registered

The registration cites its contribution to the historic landscape. The Agency for Cultural Affairs describes the Kosaka Family Residence Main House as a large dwelling that shows the traits of farmhouses in Hokushin, the northern part of Nagano Prefecture.

Two things underpin that judgment. The first is the plan: an earthen-floored Doma occupies the east end, and the raised floor is laid out in three rows, with two reception rooms placed one behind the other in the upper row. The second is condition. Heavy posts and beams remain exposed around the doma, and the joinery of the reception rooms is well preserved.

Work and cooking, family life and the receiving of guests each have their own zone under one roof, a sensible arrangement for a household that served as village headmen.

What to Look For: The Thatched Roof and Its Raised Vent

The roof defines the building. It is a hipped roof of thatch, topped by a second, smaller thatched roof along the ridge, a koshi-yane. This raised vent typically lets smoke from the hearth escape and draws light and air into the doma below.

Of the eight registered structures on the property, only the Kosaka Family Residence Main House is thatched. Every storehouse and gate around it is tiled, so a single thick straw roof sits at the center of a ring of plastered walls and fired clay.

Visiting the Kosaka Family Residence Main House

The Kosaka Family Residence Main House belongs to a private owner. The interior is closed and the grounds cannot be entered. Because the house stands in the middle of the plot, only limited views are possible from the surrounding lanes. If you take photographs, keep to the exterior as seen from the road and respect the household's privacy.