Imai Family Residence (Imai Okoyasumi Honjin) Watermill Hut

What the Watermill Hut Is

Imai Family Residence (Imai Okoyasumi Honjin) Watermill Hut stands along the watercourse running down the western edge of the grounds at Imai in Okaya City, Nagano Prefecture; it is Meiji-era work and became a Registered Tangible Cultural Property on 14 October 1999.

The channel enters the property from the north and runs south along that edge, and the hut was set inside the grounds to follow it. The building is two storeys of timber, walled in boards, under a Kirizuma-zukuri gabled roof, with a footprint of 7.3 square metres.

By floor area it is among the smallest of the eleven buildings on the estate. That it was still given two storeys suggests the power taken from the wheel shaft was divided between levels.

Why It Was Registered

Imai Family Residence (Imai Okoyasumi Honjin) Watermill Hut was listed as contributing to the historic landscape. Beyond its part in the estate, the citation notes how few working watermill huts still stand.

A mill hut is by nature short-lived. It sits in the wet, it carries moving parts, and once the machinery goes there is rarely a reason to rebuild on the spot. Survival is the exception, and a Meiji hut still standing in its own grounds is itself the value here.

What to Look For

Follow the water first. The channel comes from the north along the western edge, and the hut sits on that line. The stream was there before the building, and it fixed where the building could go; the order is legible on the ground.

The plain boarded walls are worth a look. Set against the thickly plastered storehouses on the same estate, this is simply boards nailed round a frame. Where spray and damp never stop, being able to replace a rotten board mattered more than shutting the weather out.

Keep the figure of 7.3 square metres in mind. Imai Family Residence (Imai Okoyasumi Honjin) Watermill Hut covers about the area of four and a half tatami mats, against the 450 square metres of the main house at the southern end of the same grounds.

Visiting

Imai Family Residence (Imai Okoyasumi Honjin) Watermill Hut lies on the western edge of the grounds, behind and to the west of the main house as seen from the old Nakasendo. Only a little of it can be made out from the road, and foliage hides it in some seasons.

The estate is a private residence; the grounds cannot be entered and the interiors are closed. The watercourse runs inside the property, so it cannot be approached either. Photograph from the road. The cultural properties staff of the Okaya City Board of Education can advise on access. (Checked in September 2026.)