Imai Family Residence (Imai Okoyasumi Honjin)

What Imai Family Residence (Imai Okoyasumi Honjin) Is

Imai Family Residence (Imai Okoyasumi Honjin, 今井家住宅（今井御小休本陣）) is a walled estate in Imai, Okaya City, Nagano Prefecture, standing in the former village of Imai at the eastern foot of the Shiojiri Pass on the Nakasendō highway, and its main house and ten further structures, eleven buildings in all, were entered on the national register as Registered Tangible Cultural Properties on 14 October 1999.

The Imai family served for generations as village headmen. The estate was set aside as a resting place for the lords of the Takashima domain on their circuits of inspection, and for the daimyō processions travelling to and from Edo under the alternate attendance system. The phrase okoyasumi honjin in the name records exactly that duty: a house of rest, not a lodging.

The buildings span a long stretch of time. The oldest, the plank storehouse, goes back to the middle of the Edo period; the main house dates from 1772, the rice storehouse from 1789, the document storehouse from 1861. The lumber storehouse, lumber shed, watermill hut and middle gate are Meiji-period work, and the household shrine was rebuilt in the early Shōwa era. Two and a half centuries of building campaigns sit inside one set of walls.

A Rest House Below the Pass

Records published by the city of Shiojiri explain the arrangement. The earliest Edo-period route of the Nakasendō left Shimosuwa by way of the Ono Pass, and was rerouted over the Shiojiri Pass after little more than a decade. That pass ran for over one ri with no houses along it, which made the daimyō processions hard going, so rest stations known as okoyasumijo, or teahouse honjin, were established at Imai village on the Suwa side and at Kakizawa village on the Shiojiri side. Imai Family Residence (Imai Okoyasumi Honjin) is the Suwa-side station.

This was never a post town, so no traveller slept here. A lord or an official stopped for tea and a rest, either before the climb or at the end of the descent. Pass through the front gate and the sightline runs straight to the formal entrance with its Shikidai step, a plan that still shows the rank of the household that kept it.

How the Estate Is Laid Out

The front gate faces the old Nakasendō, a Yakuimon with a 5.1 metre frontage. Inside it the main house stands directly ahead, with the middle gate and an earthen wall cutting the entrance forecourt off from the garden. A stone-lined well sits against the east side of the main house.

The ancillary buildings gather to the north and north-west. The plank storehouse stands towards the north-east, with the lumber shed behind it against the estate woodland. The document storehouse occupies the north-west corner, with the rice storehouse next to the north and the lumber storehouse beyond that. A watercourse runs down the western edge of the grounds from the north, and the watermill hut stands along it. At the northern end of that same edge, a small household shrine faces south from a stone-faced platform.

The storehouses are separated by what they held: documents in one, rice in another, construction timber in the lumber and plank storehouses, with the lumber shed serving as the sawing floor. At Imai Family Residence (Imai Okoyasumi Honjin) the formal face turned towards the highway and the working yard that supported the household have both survived, and they are still clearly distinct.

Eleven Registered Buildings

The eleven buildings of Imai Family Residence (Imai Okoyasumi Honjin) became Registered Tangible Cultural Properties on 14 October 1999, with the public notice issued on 28 October of the same month. Each structure was registered separately. The main house, the document storehouse and the rice storehouse were listed under the criterion for works that cannot easily be recreated; the front gate, middle gate, plank storehouse, lumber storehouse, lumber shed, watermill hut, well and household shrine were listed as contributing to the historic landscape of the country.

The split in criteria matches a split in character. Three buildings were valued for their scale and craftsmanship; the remaining eight were recognised as parts that make the estate read as a whole. That is why a household shrine with a footprint of 1.1 square metres and a watermill hut of 7.3 square metres are on the list at all.

Visiting and Access

Imai Family Residence (Imai Okoyasumi Honjin) is a private home and the interior is not open. Viewing means looking at the exteriors from the public road that was once the Nakasendō. Stay off the grounds and take photographs from the road. For any question about access or a possible opening, contact the cultural properties staff of the Lifelong Learning Division of the Okaya City Board of Education on 0266-78-8522 before travelling.

The estate lies about 3 kilometres north of Okaya Station on the JR Chūō Main Line, roughly 10 minutes by car. Okaya City's community bus, the Silky Bus, runs its Imai-Osachi route through the Imai district, with stops including Imai-nishi and Imai-kōsaten-kita. The fare is a flat 150 yen for adults. No visitor parking has been published, so drivers should avoid leaving a car on the road.

The lane in front of the estate is the old Nakasendō itself, climbing west towards the Shiojiri Pass. Standing at the gate, you feel the gradient that made this a place worth stopping. (Access and viewing details checked in September 2026.)