The Last Board-Roofed Farmhouse in Chichibu
The Former Arai Family Residence (旧新井家住宅, Kyū Arai-ke Jūtaku) is an eighteenth-century farmhouse at 1164 Nagatoro, Nagatoro Town, Chichibu District, Saitama Prefecture, designated an Important Cultural Property in 1971 and open to the public in the grounds of the Nagatoro Town Local History Museum.
Its roof is the reason to come. Instead of the thatch that most people picture on an old Japanese farmhouse, the main roof is laid with split chestnut boards, held down by stones set along the slope. No mortar, no nails at the surface, no elaborate ridge. Rain runs off the grain of the wood, and the weight of the stones does the rest.
Roofing of this kind was once ordinary across the Chichibu basin, where chestnut was abundant and thatching grass was not always easy to gather in quantity. Nagatoro Town's own account is blunt about how the balance has shifted: board roofs were formerly seen as often as straw ones in this district, and the Arai house is now the only survivor.
The building measures roughly 17 metres along the ridge and 10 metres across, under a gabled roof. It rises two storeys, the upper level giving the space that silkworm rearing demanded of Chichibu households well into the twentieth century. A lean-to on the east side is thatched, and the eaves extensions along the west and north faces are covered with cedar bark, so three different traditional roofing materials meet on one structure. The designation also covers a separate privy building as an attached item, a category Japanese heritage law uses for subsidiary structures that belong to the main property.
A Prayer Tablet in the Rafters
Dating a farmhouse is usually guesswork. Rural carpenters left no drawings, families rebuilt piecemeal, and stylistic argument only narrows a date to a few decades. The Arai house escaped that problem because someone climbed into the roof space and found a prayer tablet.
The tablet had been issued by Mitsumine-san Kōun-ji, the temple that became Mitsumine Shrine after the separation of Buddhism and Shinto in the Meiji era, and it carried the year Enkyō 2, corresponding to 1745. Tablets of this sort were obtained at the time of construction and fixed in the roof for protection, so the find gave the house a firm anchor in the mid-Edo period. The national record accordingly gives the date as around 1745.
The Agency for Cultural Affairs praises the house for its large living room and for the thickness of the posts and beams around that room and the earthen-floored work area, characteristics it describes as thoroughly agricultural, and it treats the building as the representative example of the board-roofed farmhouse type once widespread in Chichibu. Designation followed on 22 June 1971, under designation number 01795.
The house was not standing here then. It stood at Nakanoue, a few kilometres away near the present town hall, and the official name still carries its old address: the parenthetical note reads "formerly located in Nogami Town, Chichibu District", the municipal name in use at the time of designation, which later became Nagatoro Town. The Arai family gave the building to the town, which dismantled and reconstructed it on the museum site. Nagatoro Town's own page dates that work to 1974; some other accounts place the completion in March 1975. Anyone citing a precise year should note the discrepancy.
Relocation always costs a building something. Set apart from its original fields, lanes and neighbours, a farmhouse becomes an exhibit. The compensating gain here is straightforward: a board roof needs constant attention, and a private family in the 1970s could not reasonably have been asked to maintain one indefinitely.
What the Interior Shows
Visitors reach the house through the Nagatoro Town Local History Museum, which opened in 1980 and stands immediately in front of it. One ticket covers both.
Inside, the plan is an earthen-floored doma together with four raised rooms floored above ground level. The formal zashiki at the back has no ceiling boards, so the roof structure is visible from the mats, and the smoke of the hearth once passed straight up through it. The posts are zelkova and chestnut, dressed with an adze rather than a plane, and the tool marks remain legible as shallow facets across the surface. Stand close and the light picks them out.
The beams over the doma are heavy timbers, left rough from the axe. The contrast between that structural bluntness and the delicacy of the alcove at the far end of the house says something about how a headman's family in mid-Edo Chichibu allocated its resources: solidity where the building had to work, refinement where guests were received.
The museum itself covers Nagatoro from prehistory to the modern period, with particular attention to the geology that made the town famous. The Iwadatami rock terraces along the Arakawa, a nationally designated Place of Scenic Beauty and Natural Monument, lie a short walk away, and Hodosan Shrine sits at the foot of the mountain to the north.
Practical details, current at the time of writing and worth reconfirming with the town. Opening is 10:00 to 17:00, shortening to 16:00 from October through March. The museum closes on Mondays, moving to the following day when a Monday falls on a public holiday, and over 29 December to 3 January. Admission is 200 yen for adults and 100 yen for elementary and junior high school students, with a discount for groups of twenty or more and for visitors presenting a disability certificate. Free parking is available. Several travel listings give opening times of 9:00, which conflicts with the town's own published hours, so check before setting out. The walk from Nagatoro Station on the Chichibu Railway takes about eight minutes.
The interior is open to visitors and can be entered, which is not true of every designated farmhouse in Japan. No photography restriction is published for the building, but the museum galleries in front of it may be handled differently, so a word at the reception desk settles the matter.
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Q&A
- Can I go inside the Former Arai Family Residence in Nagatoro?
- Yes. The interior is open to visitors, and you enter through the Nagatoro Town Local History Museum standing in front of it. A single admission covers the museum and the house.
- What are the opening hours and admission for the Former Arai Family Residence?
- Nagatoro Town publishes 10:00 to 17:00, shortening to 16:00 from October through March, with closure on Mondays (the following day when a Monday is a public holiday) and from 29 December to 3 January. Admission is 200 yen for adults and 100 yen for elementary and junior high school students. Some travel sites list a 9:00 opening, so confirm with the town first.
- Why is the Former Arai Family Residence roofed with boards instead of thatch?
- Split-board roofing weighted with stones was a normal Chichibu technique, suited to a district with plentiful chestnut timber. Board and straw roofs were both common here in earlier centuries, and this house is the only board-roofed example left in the district, which is a large part of why it was designated.
- How was the Former Arai Family Residence dated to 1745?
- A prayer tablet dated Enkyō 2 (1745), issued by Mitsumine-san Kōun-ji, the temple now known as Mitsumine Shrine, was found in the roof space. Tablets like this were installed at the time of building, so the find provides a construction date rather than a stylistic estimate.
- Why does the official name of the Former Arai Family Residence mention Nogami Town?
- The house originally stood at Nakanoue in what was then Nogami Town, and was designated there in 1971 before being moved to its present site in Nagatoro. Japanese designation practice keeps the original location in the formal name, so the record reads "formerly located in Nogami Town, Chichibu District". Nogami Town later became Nagatoro Town.
- How do I reach the Former Arai Family Residence by train?
- Take the Chichibu Railway to Nagatoro Station; the walk is about eight minutes. Free parking is available for drivers, and the Iwadatami rock terraces and Hodosan Shrine are both within easy reach on foot.
Basic Information
| Name | Former Arai Family Residence, formerly located in Nogami Town, Chichibu District, Saitama Prefecture (旧新井家住宅) |
|---|---|
| Location | 1164 Nagatoro, Nagatoro Town, Chichibu District, Saitama Prefecture |
| Designation | Important Cultural Property (Structure); designation number 01795; category, pre-modern folk dwelling |
| Year Designated | 22 June 1971 |
| Quantity | 1 building; one privy included as an attached item |
| Dimensions | Approx. 17.0 m along the ridge by 10.0 m in depth; gabled, two storeys, board-roofed; thatched lean-to on the east face; cedar-bark eaves extensions on the west and north faces; built around 1745 |
| Owner | Nagatoro Town |
| Public Access | Open, interior accessible. 10:00 to 17:00 (to 16:00 from October to March). Closed Mondays (following day if a public holiday) and 29 December to 3 January. Adults 200 yen, elementary and junior high school students 100 yen. Free parking. |
References
- Agency for Cultural Affairs, National Cultural Properties Database: Former Arai Family Residence
- https://kunishitei.bunka.go.jp/heritage/detail/102/460
- Nagatoro Town: Former Arai Family Residence
- https://www.town.nagatoro.saitama.jp/nagatoro-2/araike/
- Nagatoro Town: Local History Museum and Former Arai Family Residence
- https://www.town.nagatoro.saitama.jp/nagatoro-2/siryokan/
Last verified: 2026.08.09