About the Iwao Family Residence Annex
The Iwao Family Residence (Former Nihongan Pharmaceutical Works) Annex (岩尾家住宅（旧日本丸製薬所）離れ, Iwao-ke Jūtaku Hanare) is a 2-storey wooden building of the early Meiji era in Mameda-machi, Hita City, Oita Prefecture, and it became a Registered Tangible Cultural Property on January 31, 2003. It stands behind the main house, joined to it by a 2-storey connecting corridor. Roofed in Sangawara-buki pantiles and with a footprint of 60 square meters, it holds a toilet, a bathroom and a Zashiki reception room.
The annex is the oldest of the three registered buildings of the Iwao Family Residence. It sits in a quiet corner of the plot, out of sight behind the main house and storehouse that line the street.
Why It Was Registered
The Iwao Family Residence Annex was registered as a building that would be difficult to reproduce. Where the main house and storehouse were valued for their contribution to the townscape, the annex was valued above all for the finish of its interior.
The Agency for Cultural Affairs dwells longest on the toilet. Its exterior is finished in Shikkui lime plaster polished to a glossy black, and inside are walls of marble and of plaster worked to imitate marble, with large mirrors set into the walls. The agency calls the whole room an exercise in luxury, and describes the reception room as small but properly built. Few households ever lavished this much craft on a washroom, and matching it today would take both rare plastering skill and a patron's deep pockets.
The Retirement Room Beyond the Corridor
Toward the end of the second-floor route, the Nihongan-kan shows a room it calls the intaku, or retirement room. Iwao Shotaro, the fifteenth head of the family, used it after handing over the business, and the museum places it in a quiet spot reached through a connecting corridor. Because this matches where the Agency for Cultural Affairs puts the 2-storey corridor and the reception room of the annex, the retirement room appears to be the zashiki of the Iwao Family Residence Annex.
From the corridor you can look down into an inner courtyard where, according to the museum, a small waterfall once ran. Walk it as the retreat of a man who had made a fortune from Nihongan pills and wanted distance from the bustle of the street.
Seeing and Visiting the Iwao Family Residence Annex
Because it stands behind the main house, the Iwao Family Residence Annex can hardly be seen from the street. To see it, enter the Nihongan-kan and follow the second-floor corridor to the retirement room. The museum opens February 15 to May 31 in spring and September 1 to November 30 in autumn, 10:00 a.m. to 4:00 p.m., with adult admission of 400 yen. These details were checked on the official Nihongan-kan website on October 6, 2026.
The museum's own guide does not make clear whether the toilet and bathroom described by the Agency for Cultural Affairs are on the visitor route. If you hope to see them, or to take photographs, please ask at the reception desk.
- 📍 Plan Your Visit to Oita
- Find tours, activities & transport passes near Iwao Family Residence (Former Nihongan Pharmaceutical Works) Annex
- [ Beppu Hell Tour & Yufuin Onsen Hot Springs ]
Q&A
- When was the Iwao Family Residence Annex built?
- It dates from the early Meiji era and is the oldest of the three registered buildings.
- What is inside the Iwao Family Residence Annex?
- A toilet, a bathroom and a reception room. The toilet is finished outside in polished black plaster and inside with marble and large mirrors.
- Why is the Iwao Family Residence Annex a Registered Tangible Cultural Property?
- The lavish finish of its toilet and its properly built reception room were judged difficult to reproduce. It was registered on January 31, 2003.
- What is the retirement room in the Iwao Family Residence Annex?
- The Nihongan-kan shows it as the room Iwao Shotaro, the fifteenth head of the family, used in retirement. It lies beyond the connecting corridor and appears to be the annex's reception room.
- Can the Iwao Family Residence Annex be seen from the street?
- Hardly, since it stands behind the main house. Visit it from inside during the Nihongan-kan's open seasons.
Basic Information
| Name | Iwao Family Residence (Former Nihongan Pharmaceutical Works) Annex |
|---|---|
| Location | 4-15 Mameda-machi, Hita City, Oita Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered January 31, 2003 |
| Quantity | 1 building |
| Dimensions | 2-storey wooden building, tiled roof, building area 60 square meters |
| Owner | Not listed in the Agency for Cultural Affairs database (opened to the public by Iwao Yakuho as the Nihongan-kan) |
| Public Access | Open in spring and autumn as the Nihongan-kan (10:00 a.m. to 4:00 p.m.; adults 400 yen) |
References
- Database of National Cultural Properties: Iwao Family Residence (Former Nihongan Pharmaceutical Works) Annex (Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/101/00003181
- Nihongan-kan official website
- https://www.nihongan.info/
- Nihongan-kan: Guide to the Building
- https://www.nihongan.info/s-projects-side-by-side
Last verified: 2026.10.06
