A Thatched Farmhouse from the Late Eighteenth Century
Iwasaki Family Residence Main House (岩崎家住宅主屋, Iwasaki-ke Jūtaku Shuoku) is a thatched farmhouse in Inokuchi, Aki City, Kochi Prefecture, built around 1795 and registered as a Registered Tangible Cultural Property on 28 April 2010. It is best known as the birthplace of Iwasaki Yatarō, founder of Mitsubishi, who was born here on 9 January 1835, and it stands at the centre of the Iwasaki Family Residence grounds, facing south.
Tradition credits the house to Yatarō's great-grandfather, Yajiemon. It is a single-storey timber building 12 metres across the front and 9.4 metres deep, with a building area of 104 square metres. The hipped roof is Kayabuki thatch. Tiled lean-to eaves (Geya) run along the front and back, while on both sides the thatch sweeps down almost to head height. The house was repaired in 1980.
Inside, an earth-floored Doma occupies the western end and four raised rooms fill the east, laid out in the kuichigai yon-madori pattern, where the partitions do not line up. The front reception room has a Tokonoma and a side alcove. The Aki City Tourist Association describes an eight-mat front room, two rooms of four and a half mats beside it, and a nine-mat living room, the chanoma, with the Toriniwa passage running along its left side.
Registered for Its Design
Of the seven structures at the Iwasaki Family Residence, only the Iwasaki Family Residence Main House was registered as a model of design. The other six, including the storehouses and the guardhouse, were registered for their contribution to the historic landscape. The Agency for Cultural Affairs calls the house a fine example of a small farmhouse dating back to the eighteenth century.
The point is survival rather than grandeur. A modest rural house has kept its original bones: the doma, the four-room raised floor and the front room with its alcove, the ordinary arrangement of a Tosa farming household in the Edo period. The registration recognises the building on its own terms, not only as a famous man's birthplace.
Yatarō grew up here until he left for Edo to study in 1854. That the house of his boyhood was never enlarged or westernised, and still reads plainly as a farmhouse, is part of what makes it worth the trip.
What to Look for from the Doma
Visitors may go as far as the doma. Stand inside the entrance and the raised rooms open to your right, on the east, with the chanoma at the back. The roof space above is tall and dark with old smoke, a sharp contrast with the pale thatch outside.
Beneath the chanoma floor is an imotsubo, a pit for storing sweet potatoes and other tubers. Crouch down from the passage and you can see into it. It is easy to miss and one of the clearest signs of how the household actually lived.
Outside, watch the roofline. Front and back, the tiled eaves cut off the bottom of the thatch; on the sides, the thatch comes low, so the whole mass of the roof seems to settle toward the ground. Walk round to either side to see how thatched hip and tiled lean-to meet. In front of the Iwasaki Family Residence Main House is a small garden of set stones, which by tradition the boy Yatarō arranged to resemble the Japanese archipelago.
Visiting the Main House
The exterior can be viewed free of charge during the grounds' opening hours, and visitors may step into the doma. The raised rooms are off limits. Because the roof is thatch, fire and smoking are banned throughout the grounds.
Press and other filming requires the owners' permission, arranged through Aki City. Opening hours, closing days and directions are covered on the Iwasaki Family Residence page.
Q&A
- When was the Iwasaki Family Residence Main House built?
- Around 1795, reportedly by Iwasaki Yatarō's great-grandfather Yajiemon. It was repaired in 1980.
- Can you go inside the Iwasaki Family Residence Main House?
- Only as far as the earth-floored doma, from where you can look into the rooms and the potato pit. The raised rooms cannot be entered. Admission is free.
- Why is the Iwasaki Family Residence Main House a Registered Tangible Cultural Property?
- It was registered on 28 April 2010 as a model of design, described by the Agency for Cultural Affairs as a fine example of a small farmhouse dating back to the eighteenth century.
- What is the floor plan of the Iwasaki Family Residence Main House?
- An earth-floored doma at the west end and four raised rooms to the east in a staggered layout: an eight-mat front room, two four-and-a-half-mat rooms and a nine-mat living room, with an alcove in the front room.
- Is the Iwasaki Family Residence Main House the birthplace of Iwasaki Yatarō?
- Yes. The founder of Mitsubishi was born in this house on 9 January 1835.
Basic Information
| Name | Iwasaki Family Residence Main House (岩崎家住宅主屋) |
|---|---|
| Location | 1696 Ko, Inokuchi, Aki City, Kochi Prefecture, and adjoining lots |
| Designation | Registered Tangible Cultural Property (structure), registration no. 39-0253 |
| Year Designated | Registered 2010/04/28 (Heisei 22) |
| Quantity | 1 structure |
| Dimensions | Single-storey timber building, hipped thatched roof; building area 104 m²; 12 m by 9.4 m |
| Owner | Private (Iwasaki family) |
| Public Access | Exterior free to view; interior closed, entry as far as the doma |
References
- National Cultural Properties Database, Agency for Cultural Affairs: Iwasaki Family Residence Main House
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00008200
- Cultural Heritage Online: Iwasaki Family Residence Main House
- https://bunka.nii.ac.jp/heritages/detail/168921
- Aki City: Iwasaki Yataro Birthplace (Japanese)
- https://www.city.aki.kochi.jp/life/dtl.php?hdnKey=45
Last verified: 2026.09.25
