The Most Developed Gassho-Style House
The Iwase Family Residence (Kamitaira Village, Higashitonami District, Toyama Prefecture) (岩瀬家住宅（富山県東砺波郡上平村）) is a gassho-style farmhouse at Nishiakao-machi in the Gokayama area of Nanto City, Toyama Prefecture, which in 1958 was designated an Important Cultural Property.
The Agency for Cultural Affairs records a building 23.9 by 13.0 metres, one storey with four levels under a gabled thatched roof, with metal-roofed aisles on all four sides.
The Agency notes that it was originally the house of the Fujii family, who refined saltpetre for the domain.
The House
According to the Agency, the gabled thatched roof encloses four levels, with metal-roofed aisles around all four sides.
At 23.9 metres long, it is exceptionally large for a gassho-style house.
What to Look For
The Agency dates it to the end of the Edo period and considers it the most developed form of gassho-style house in the Sho River basin.
The official Gokayama tourism site describes it as the largest gassho-style house in Japan, built over eight years in the mid-eighteenth century as a sign of the Kaga domain's authority. The two sources differ on the date.
Visiting the Iwase Family Residence (Kamitaira Village, Higashitonami District, Toyama Prefecture)
Check visiting arrangements with the Gokayama tourism office or the Iwase family.
Q&A
- When was the Iwase residence designated?
- On 14 May 1958.
- How big is it?
- 23.9 by 13.0 metres.
- Whose house was it originally?
- The Fujii family, saltpetre refiners, according to the Agency.
- Why is it important?
- It shows the most developed gassho style of the Sho River basin.
- When was it built?
- Late Edo per the Agency; the mid-eighteenth century per the Gokayama tourism site.
Basic Information
| Name | Iwase Family Residence (Kamitaira Village, Higashitonami District, Toyama Prefecture) (岩瀬家住宅（富山県東砺波郡上平村）) |
|---|---|
| Location | 857-1 Nishiakao-machi, Nanto City, Toyama Prefecture |
| Designation | Important Cultural Property (building) |
| Year Designated | Designated 1958/5/14 (Showa 33) |
| Quantity | 1 building |
| Dimensions | 23.9 by 13.0 metres, four levels, gabled, thatched, with metal-roofed aisles |
| Owner | Not recorded in the Agency for Cultural Affairs database |
| Public Access | Check visiting conditions locally |
References
- Agency for Cultural Affairs Database: Iwase Family Residence (Japanese)
- https://kunishitei.bunka.go.jp/bsys/maindetails/102/746
- Cultural Heritage Online: Iwase Family Residence (Japanese)
- https://online.bunka.go.jp/heritages/detail/184896
- Gokayama Official Tourism Site: Iwase House (Japanese)
- https://gokayama-info.jp/archives/769
Last verified: 2026.09.29