A Tokyo Station Architect's Late Work, in a Temple Garden
The former Ōta Residence main house (旧太田家住宅主屋, also written Kyū Ōta-ke Jūtaku Omoya), known at its present home as Hōzen-in Sanmaya-an (宝善院三摩耶庵), is a hybrid Japanese and Western timber house of 1936 standing on the grounds of Hōzen-in temple at Koshigoe in Kamakura, Kanagawa Prefecture, and it was entered on the national register of Tangible Cultural Properties on 17 August 2020.
The architect was Kasai Manji.
That name is less familiar outside Japan than it should be. Kasai, who lived from 1863 to 1942, was born in Morioka, graduated from the Imperial University's architecture department in 1890, joined the Bank of Japan as an engineer, and there began working under Tatsuno Kingo. In 1903 the two men opened the Tatsuno Kasai office, one of the first private architectural practices in the country. Their firm designed the Marunouchi building of Tokyo Station, completed in 1914 and now an Important Cultural Property.
Kasai was seventy-three when this house went up in Kamakura. Tokyo Station was twenty-two years behind him, Tatsuno seventeen years dead. Domestic commissions of this scale from the end of his career are not commonly encountered.
How the House Is Put Together
The building covers 307 square metres, single-storey with a partial second floor, under a hipped tile roof. A corridor runs through the middle of the plan, with the Japanese rooms placed to its south so that they open onto the garden through a wide veranda.
The southwest corner is where the design turns. There the exterior becomes Western in character, with an entrance porch and Western rooms. So the house presents two faces depending on the approach: a tiled Japanese roof and garden-facing veranda from one side, a porched Western elevation from the other, and both belong to the same building without a visible seam.
Kasai's generation had spent careers translating European structural and decorative vocabulary into Japanese practice. In banks and stations that meant brick, stone and iron. In a private house on the Shōnan coast it meant something quieter: knowing which rooms should be Western and which Japanese, and making the joint between them read as a decision rather than a compromise. The Agency for Cultural Affairs assessment uses the phrase that the two idioms are skilfully fused.
An extension was added in 1941, five years after completion and a year before Kasai's death. Published sources do not record who designed it.
Visitors who have written about the building note the reddish ochre wall colour, the unusual treatment of the upper storey, and a hipped roof whose slope is not a simple plane. The lattice work of the entrance is worth a look for the care given to a detail that most houses treat as standard joinery.
Why It Was Registered
Registered Tangible Cultural Property is the lighter of Japan's two systems for protecting historic buildings. Created in 1996 for structures more than fifty years old, it requires owners to notify the authorities before significant alteration and gives tax relief in return. Important Cultural Properties and National Treasures are designated instead, which brings strict controls on repair together with substantial public funding.
This house was registered under the criterion covering structures that serve as a model of design, with the number 14-0283.
Kamakura holds an unusually dense collection of pre-war villas and residences, and the city has been steadily adding them to the register. Reading the Ōta house alongside them clarifies what it contributes: not scale, and not aristocratic pedigree, but the hand of a first-generation professional architect applied to an ordinary domestic programme.
The Temple That Owns It
The house now belongs to Hōzen-in, a Shingon temple in the Koshigoe district of southwestern Kamakura. The temple carries two mountain and temple names, Kajisan Ryōzenji and Taichōsan Rurikōji, and its principal image is a standing wooden Yakushi Nyorai, the Buddha of healing.
Hōzen-in dates its founding to a visit by the monk Taichō, though accounts of the year differ: the temple gives 723, while other sources place it in the Tenpyō-jingo era of the 760s. Taichō was known as the Great Virtue of Koshi, the northern provinces of Echizen, Etchū and Echigo, and is credited with opening Mount Hakusan to religious practice. The temple's account holds that he enshrined an eleven-headed Kannon image here, and that this was its beginning.
Through the Edo period Hōzen-in served as the administrative temple of Ryūkō Myōjin shrine, which honours the five-headed dragon of Enoshima legend. The name Sanmaya-an now carried by the house comes from the Sanskrit term samaya, a concept central to esoteric Buddhist practice and appropriate to a Shingon precinct.
Visiting
Set expectations carefully. The building stands just before the temple gate and looks, from the approach, like a private house. A visitor who wrote up a trip in 2021 described walking straight past it on a first attempt without realising what it was. There is no admission system, no published opening, and no interior access.
What is possible is to walk the temple approach, see the exterior from the public path, and combine the visit with the temple itself. Photography of a building in daily use calls for restraint, and asking at the temple office before pointing a camera is the sensible course.
Hōzen-in is about twelve minutes on foot from Koshigoe Station on the Enoshima Electric Railway, the single-car tram line that runs between Kamakura and Fujisawa, and about the same from Mejiroyamashita Station on the Shōnan Monorail. Enoden buses stop at Koshigoe Chūgakkō Iriguchi, five minutes away. Enoshima and Ryūkōji temple are within easy walking distance, and Manpukuji, associated with Minamoto no Yoshitsune, is close to Koshigoe Station.
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Q&A
- Where is the former Ōta Residence main house (Hōzen-in Sanmaya-an), and how do I get there?
- It stands on the grounds of Hōzen-in temple at 306-1 Koshigoe 5-chōme, Kamakura, Kanagawa Prefecture. Walk about twelve minutes from Koshigoe Station on the Enoshima Electric Railway, or a similar time from Mejiroyamashita Station on the Shōnan Monorail. The Koshigoe Chūgakkō Iriguchi bus stop is five minutes away.
- Can visitors go inside the former Ōta Residence main house?
- No. The building is in use and there is no public opening of the interior and no admission scheme. It can be seen from the temple approach, standing just before the gate. Ask at the temple office before photographing.
- Who designed the former Ōta Residence main house?
- Kasai Manji, who lived from 1863 to 1942. With his teacher Tatsuno Kingo he founded the Tatsuno Kasai office in 1903, one of Japan's earliest private architectural practices, and the two designed the Marunouchi building of Tokyo Station. He was seventy-three when this house was built in 1936.
- Why is the former Ōta Residence main house called Hōzen-in Sanmaya-an?
- The house passed into the ownership of Hōzen-in, a Shingon temple in Koshigoe, and stands on its grounds. Sanmaya comes from the Sanskrit samaya, a term from esoteric Buddhist practice. The register records both the original family name and the current temple name.
- What makes the former Ōta Residence main house architecturally interesting?
- Japanese and Western elements are combined within one plan. A central corridor puts the Japanese rooms on the south side facing the garden across a wide veranda, while the southwest corner takes a Western exterior with an entrance porch and Western rooms. The house covers 307 square metres under a hipped tile roof.
Basic Information
| Name | Former Ōta Residence main house (Hōzen-in Sanmaya-an) / 旧太田家住宅主屋（宝善院三摩耶庵） |
|---|---|
| Location | 306-1 and others, Koshigoe 5-chōme, Kamakura, Kanagawa Prefecture |
| Designation | Registered Tangible Cultural Property (Structure), register no. 14-0283; criterion: a model of design |
| Year Designated | Registered and notified 17 August 2020 |
| Quantity | 1 building |
| Dimensions | Timber frame, single storey with partial second floor, tiled hipped roof, floor area 307 m². Built 1936; extended 1941 |
| Owner | Hōzen-in (religious corporation) |
| Public Access | Interior closed. Exterior visible from the temple approach; no admission scheme |
References
- National Database of Designated Cultural Properties, Agency for Cultural Affairs: former Ōta Residence main house (Hōzen-in Sanmaya-an)
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00013370
- Cultural Heritage Online: former Ōta Residence main house (Hōzen-in Sanmaya-an)
- https://bunka.nii.ac.jp/heritages/detail/380547
- Morioka City: Kasai Manji
- https://www.city.morioka.iwate.jp/kankou/kankou/1037106/1009526/1024995/1024997/1025089.html
- Tokyo National Research Institute for Cultural Properties, obituary archive: Kasai Manji
- https://www.tobunken.go.jp/materials/bukko/8550.html
- Kamakura City Tourist Association: Hōzen-in
- https://www.trip-kamakura.com/place/222.html
- Kamakura City: list of designated cultural properties
- https://www.city.kamakura.kanagawa.jp/treasury/shiteibunkazai-kensu-list.html
Last verified: 2026.08.13