Kumagai Family Residence (Toyone Village, Kitashitara District, Aichi Prefecture)

A Mountain House Built on the Wrong Measurements

The Kumagai Family Residence (熊谷家住宅, Kumagaike Jutaku) is a mid-Edo-period farmhouse complex at Oidaira, Kamikurokawa, Toyone Village, Kitashitara District, Aichi Prefecture, whose three buildings, the main house, the grain storehouse and the new storehouse, were designated Important Cultural Properties on 5 February 1974.

The site sits in the Okumikawa mountains, close to where the old provinces of Mikawa, Shinano and Totomi met. The Oiri River, a tributary of the Tenryu, runs below. The road through the valley was once a branch of the Nakama highway, the packhorse route running up from Sakuma in Totomi toward Tsugu and Neba, and the Kumagai house stood at a checkpoint along it.

The family served as village headmen for the mountain district and brewed sake commercially until the late 1930s. Household tradition holds that the first Kumagai, a man named Genba, came south from Shinano and opened the Kurokawa valley for settlement. No document confirms this. What the surviving evidence does support is standing: a family that held the headman's post for generations, kept a formal residence, and raised stone memorial pagodas of a type reserved for people of consequence.

Why the Column Spacing Matters

No construction record survives. Dating rests on a prayer tablet from 1744 and on the building's own peculiarities, and the current estimate places construction in the first half of the eighteenth century. The official register gives the period as mid-Edo, between 1661 and 1750.

The strongest evidence is a measurement. Japanese houses of the period were laid out on a column spacing of six shaku, sometimes six shaku three sun, roughly 180 to 190 centimetres. The Kumagai house uses seven shaku five sun: 225 centimetres. Every bay is wider than it should be, and a column stands at each one, following an older framing convention that had largely disappeared elsewhere by this date.

The floor plan compounds the anomaly. The original arrangement is a ko-mutsumadori, a six-room layout with a broad veranda running around it and a boarded kitchen area projecting toward the garden. Six-room and four-room plans of this older type are not found in ordinary farmhouses. They belong to formal samurai residences. Neither the plan nor the structural approach has parallels elsewhere in Okumikawa, and both resemble the warrior housing of the Hamamatsu area, across the mountains in Totomi.

Which suggests the builders were looking outward, not to local practice. For a family controlling a road that ran toward Totomi, that would make sense.

The house has been altered since. Between the late eighteenth and early nineteenth centuries the upper room and the storage room were reworked, with the upper room pushed out into the veranda. In the early Showa period a sleeping room and a lavatory were added and the veranda was absorbed into them. The register describes the main house as it now stands: 24.8 metres along the ridge, 13.1 metres deep, with a hipped-and-gabled thatched roof and sheet-metal eaves on the east and west faces.

The Two Storehouses and the Composition of the Site

The main house faces east. A gate stands at the centre of the east side, a simple post gate now, though it was originally a longhouse gate of the more elaborate kind. To the left of the gate stand the two designated storehouses, and a barn sits north of the main house. During the brewing years the site carried more outbuildings than survive.

Both storehouses are dozo, earthen-walled structures with thick plaster over a timber core, built to resist fire. The grain storehouse measures 5.9 by 5.0 metres, two storeys, gabled and entered from the gable end, with clay tiles above. The new storehouse is slightly smaller at 5.0 by 4.0 metres, partly two-storeyed, gabled, also tiled.

The designation report singles out the arrangement rather than the individual buildings. The two storehouses stand in front of the main house, and the group read together makes a good landscape. That phrasing comes from the assessment itself, which is unusual: designations of farmhouses more often praise a roof truss or a plan. Here the judgement covers how the buildings sit relative to one another on a hillside.

Comparison within the designation is instructive. The register places the Kumagai house alongside the Hattori residence as a wealthy rural household, then notes what distinguishes it: mountain siting, a main house that is large and unusually tall, and rooms of twelve and a half mats repeated one after another rather than varied in size.

Conservation has been continuous. Fire alarms, firefighting equipment and lightning protection went in during 1975. The thatch was replaced and both storehouses repaired across 1982 and 1983, the thatch was renewed again in 1995 and 1996, and the new storehouse was re-roofed in 2000.

Before You Go

This one requires care. The Kumagai Residence is a private home. The family still lives in the designated buildings, and the line has reached its twentieth generation. Sake sales continued from the premises in recent years, but the buildings are not a museum and there are no opening hours.

Toyone Village's official page, updated in December 2024, states that the property is closed to entry because of construction work. Anyone planning a visit should check the village's current notice first. Even when work finishes, interior access has never been routine: local tourism information describes going inside as difficult precisely because people live there.

What remains possible is the view from the road. Prefectural Route 428, the Komadate-Tsugu line, runs past the site along the Oiri River. Coming from the Toei side, the house appears on the left after the Kurokawa tunnel, set against the slope. The composition the designation praised, two storehouses in front of a tall thatched roof, is legible from outside the property line.

Photograph from the public road and keep your distance from the buildings. There is no visitor parking, no admission desk and nobody on duty to answer questions. Reaching Toyone means driving; the village lies deep in the Aichi mountains, and public transport into the valley is sparse.