What the Tozanso Main Building Is
The Tozanso Main Building (東山荘本館, Tōzansō Honkan) is a two-story wooden villa house in Kasugacho, Atami City, Shizuoka Prefecture, built in 1933 and entered on the national register as a Registered Tangible Cultural Property (structure) on August 1, 2016. It occupies the northeastern part of a hillside plot above Sagami Bay and forms the core of the seven buildings that make up the Tozanso estate.
The house was commissioned by Ishii Kengo, then president of Dai-Ichi Bank, and designed and built by Shimizu-gumi, the firm known today as Shimizu Corporation. In the spring of 1939 the property passed to Yamashita Kamesaburo, first president of the Yamashita Kisen shipping line, whose successor company is Mitsui O.S.K. Lines. A six-mat room was added behind the entrance hall the following year. In the autumn of 1944 Okada Mokichi, founder of the Church of World Messianity, acquired the estate and gave it the name Tozanso, taking the word from Higashiyama, the old name of the district now called Kasugacho.
Ishii and Yamashita had a long connection. According to the history published by the Tozanso Preservation Society, when Yamashita was starting out in shipping and could not raise capital, Ishii, then at the Yokohama branch of Dai-Ichi Bank, borrowed 30,000 yen on his own account and lent it to him. Yamashita kept the bank as his main lender until Ishii stepped down as president. Years later he bought the older man's seaside house.
Why It Was Registered
The Tozanso Main Building carries registration number 22-0224. The criterion applied to it is contribution to the historic landscape of the nation. On the same day in 2016 the main gate, detached wing, annex, tea house, storehouse and storage shed were all registered as well, so that all seven buildings on the plot became Registered Tangible Cultural Properties together.
Atami filled with the villas of bankers and industrialists in the early Showa period, as the Tanna railway tunnel promised to bring Tokyo within easy reach. Most of those houses are gone. Tozanso has kept both its buildings and its grounds of roughly 3,320 square meters, and the main house sits at the center of that survival with its original plan intact. What the register recognizes is a modern Japanese-style villa that carries its whole history, from the 1930s to the present day, in one place.
What to Look At
The Tozanso Main Building covers 240 square meters. Its roof is tiled, with copper sheeting over part of the surface.
A long corridor runs north to south through the plan and acts as the spine of the house. Only the central section on the east side of that corridor rises to two floors. Both of those floors hold two Zashiki rooms with a veranda wrapped around them. On the ground floor the entrance wing lies to the north and the bathroom to the south, so that the whole daily round of the house is contained in a single volume.
Posts and lintels throughout are noticeably slender. The carpentry borrows the methods of Sukiya-zukuri, the teahouse-derived manner that favors lightness over mass, and the effect is a room that feels more like a pavilion than a mansion. On the east face a broad sheet of glass opens the interior to Sagami Bay. That single wall says a great deal about how an early Showa villa was expected to treat a sea view.
Visitors are shown the ground-floor living room, the ground-floor bath and the second-floor bedroom. Lighting fixtures from the original fit-out, rediscovered in the estate storehouse, have been restored in recent years, so the rooms can now be seen under something close to their intended light.
Visiting
The Tozanso Preservation Society opens the estate by advance booking. Tours normally run on the third Sunday of each month, moving to the fourth Sunday in March, May, August and November. There are two starting times, 11:00 a.m. and 1:30 p.m., and each takes ten people.
Admission is 1,000 yen, paid on arrival. A guide accompanies every tour and the visit lasts about an hour. Booking is by email to the preservation society, giving name, contact details, preferred date and time, and number of people; places are allocated in the order messages arrive. In 2026 the house is closed in July and December.
No policy on photography is stated in the published information, so ask the guide on the day.
The nearest station is JR Atami Station, about a ten-minute walk southeast up a steep residential slope. There is no visitor parking on site, and paid car parks in town are the practical option.
An autumn moon-viewing evening is held once a year. The 2026 edition runs on September 25 from 5:00 p.m. to 7:00 p.m. in the Tozanso Main Building, with a fee of 1,000 yen and 60 places, again by reservation.
Q&A
- Can I visit the Tozanso Main Building, and what does it cost?
- Yes, by advance reservation. Tours run on the third Sunday of most months (the fourth Sunday in March, May, August and November) at 11:00 a.m. and 1:30 p.m., ten people per tour. Admission is 1,000 yen and the guided visit lasts about an hour. The house closes in July and December in 2026.
- Who built the Tozanso Main Building, and when?
- Ishii Kengo, president of Dai-Ichi Bank, had it built as his seaside villa in 1933, with Shimizu-gumi as designer and contractor. A six-mat room was added in 1940 under the next owner, the shipping magnate Yamashita Kamesaburo.
- How do I reach the Tozanso Main Building from Atami Station, and is there parking?
- It is roughly a ten-minute walk southeast from JR Atami Station, uphill most of the way. No parking is provided for visitors, so use one of the paid car parks in central Atami.
- What is architecturally distinctive about the Tozanso Main Building?
- Only the middle of the east side rises to two floors, and both levels hold two tatami rooms ringed by a veranda. The timber is unusually slim, in the sukiya manner, and the east elevation is largely glass, framing Sagami Bay.
- Does a visit to the Tozanso Main Building include the other buildings on the site?
- It does. The guided tour covers the grounds, so the main gate, detached wing, annex, tea house, storehouse and storage shed can be seen on the same visit. All seven were registered on August 1, 2016.
Basic Information
| Name | Tozanso Main Building |
|---|---|
| Location | 1712-5 Kasugacho, Atami City, Shizuoka Prefecture, and adjoining lots |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered on August 1, 2016 (Heisei 28) |
| Quantity | 1 building |
| Dimensions | 2-story wooden structure, tiled roof partly clad in copper sheet, building area 240 square meters |
| Owner | Church of World Messianity |
| Public Access | Open by advance reservation (3rd Sunday of most months, admission 1,000 yen) |
References
- National Designated Cultural Property Database, Tozanso Main Building (Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/101/00011139
- Tozanso, About the Buildings (Tozanso Preservation Society)
- https://touzansou.jp/about
- Tozanso, History (Tozanso Preservation Society)
- https://touzansou.jp/history
- Tozanso, Visit Booking (Tozanso Preservation Society)
- https://touzansou.jp/application
- Cultural Properties (Church of World Messianity)
- https://sekaikyuuseikyou.or.jp/culture
Last verified: 2026.09.09