Iwamotoro Roman Bath: A Registered Tangible Cultural Property on Enoshima Island
Nestled within the historic Iwamotoro Honkan ryokan on Enoshima Island in Fujisawa City, Kanagawa Prefecture, the Iwamotoro Roman Bath (岩本楼ローマ風呂) is a remarkable Western-style bathhouse dating from around 1930. Designated as a Registered Tangible Cultural Property of Japan in 2001, this extraordinary bathing chamber transports visitors to the grandeur of ancient Rome — an unexpected treasure hidden inside one of Japan's most storied inns. The ryokan itself traces its origins back over 850 years to the Kamakura period, when it served as a lodging temple called Iwamoto-in for shoguns and feudal lords visiting Enoshima Shrine.
Historical Background
The history of Iwamotoro begins in the Kamakura period (1185–1333), when the establishment known as Iwamoto-bō served as a sub-temple (bettō-ji) managing the Enoshima Iwaya caves and Okutsunomiya of Enoshima Shrine. Under the patronage of Minamoto no Yoritomo, the temple grew in stature, eventually becoming the sō-bettō — chief administrator — of all religious affairs on the island. For centuries, shoguns, imperial envoys, and daimyō lords stayed at Iwamoto-in during their pilgrimages to worship Benzaiten, the goddess of fortune.
Following the Meiji-era separation of Buddhism and Shinto (shinbutsu bunri) and the subsequent haibutsu kishaku movement of 1873, the temple's religious functions were dissolved. In 1874, Iwamoto-in reinvented itself as Iwamotoro, a ryokan (traditional Japanese inn), drawing on its long tradition of hospitality. During the early Showa period, the inn's proprietors commissioned the construction of the Roman Bath in approximately 1930, creating a boldly innovative bathing facility that blended European aesthetics with Japanese craftsmanship.
Why It Was Designated a Cultural Property
The Iwamotoro Roman Bath was registered as a Tangible Cultural Property of Japan on November 20, 2001, under the category of modern architecture (post-1926). The designation recognizes it as a structure that would be extremely difficult to reproduce today. The bathhouse is a single-story wooden building with a glass roof, covering a floor area of approximately 43 square meters. Its design draws inspiration from the horseshoe-shaped thermae (public baths) of ancient Rome, with a domed glass ceiling reminiscent of a European cathedral.
Several elements contributed to its cultural significance: the walls feature ornamental wall fountains and Venetian-window-style decorations crafted from tiles and terracotta by Komori Shinobu, a leading figure in Japan's ceramics industry during the early 20th century. The partition between the changing room and the bath chamber is fitted with a magnificent peacock-motif stained glass panel attributed to Beppu Shichirō. These Italian-made stained glass pieces are considered irreplaceable — no longer in production and valued at approximately 150,000 yen per 30-centimeter panel. Together, these artistic elements represent a unique fusion of classical Western grandeur and Japanese modernist ambition that was truly pioneering for its era.
Highlights and Attractions
Stepping into the Roman Bath is like entering a scene from a period film. The horseshoe-shaped soaking tub occupies the center of the chamber, surrounded by ornately tiled walls adorned with terracotta reliefs. Above, the glass dome ceiling floods the space with natural light, creating an atmosphere that feels worlds away from the seaside island outside. The vivid peacock stained glass door between the changing room and the bath is a particular highlight — when backlit, the colors glow with extraordinary intensity.
In addition to the Roman Bath, Iwamotoro Honkan also features the Benten Cave Bath (弁天洞窟風呂), a mystical bathing space built within a natural cave that once housed a Benzaiten shrine. The cave bath offers a dramatically different atmosphere — dim lighting, rough stone walls, and the sound of dripping water create an almost otherworldly experience. The two baths alternate between male and female use on a timed schedule, allowing overnight guests to enjoy both.
The ryokan's first floor houses a small museum displaying approximately 85 historical artifacts, including Edo-period fusuma paintings of Benzaiten, antique signboards, and documents from the inn's centuries-long history. Guest rooms on the upper floors offer panoramic views of Sagami Bay and Mount Fuji, while the evening kaiseki meals feature fresh seafood from the Shonan coast.
Surrounding Area and Nearby Attractions
Iwamotoro is located along the approach to Enoshima Shrine, placing it at the heart of one of the Shonan region's most popular tourist destinations. Enoshima Island itself is compact but rich with things to see and do. Enoshima Shrine (江島神社), comprising three sanctuaries — Hetsu-no-miya, Nakatsu-no-miya, and Okutsu-no-miya — enshrines three sister goddesses and is celebrated as one of Japan's Three Great Benzaiten shrines. The shrine grounds feature vermillion torii gates, a dragon-palace-style gate called Zuishinmon, and a sacred hall housing an important eight-armed Benzaiten statue.
Nearby, the Enoshima Sea Candle observation lighthouse offers 360-degree views from the island's summit, while the Samuel Cocking Garden showcases tropical plants in a pleasant park setting. The Enoshima Iwaya Caves, a pair of sea-carved caverns at the island's southwestern tip, have been sacred sites since ancient times. The rocky shore of Chigogafuchi, designated one of Kanagawa's 50 Best Scenic Spots, is famous for its dramatic sunsets with Mount Fuji silhouetted in the background.
The Benten Nakamise-dōri shopping street leading up to the shrine entrance is lined with seafood restaurants, souvenir shops, and food stalls selling local specialties like shirasu (whitebait) rice bowls and tako senbei (octopus crackers). The nearby Enoshima Island Spa offers a modern counterpoint to the historic baths, with natural hot springs drawn from 1,500 meters underground and ocean-view pools.
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Q&A
- Can non-guests visit the Iwamotoro Roman Bath?
- The Roman Bath is generally available only to overnight guests of Iwamotoro Honkan. To experience both the Roman Bath and the Benten Cave Bath, booking an overnight stay is recommended. The baths operate on a timed male-female rotation schedule that varies by day, so please confirm the schedule with the front desk upon arrival.
- When was the Roman Bath built, and when was it designated a cultural property?
- The Roman Bath was constructed around 1930 (Showa 5). It was registered as a national Tangible Cultural Property on November 20, 2001, in recognition of its irreplaceable architectural and artistic value.
- How do I get to Iwamotoro Honkan?
- From Katase-Enoshima Station on the Odakyu Line, it is approximately a 12-minute walk. From Enoshima Station on the Enoden Line or Shonan-Enoshima Station on the Shonan Monorail, it is about a 20-minute walk. The ryokan is located along the Enoshima Shrine approach road; vehicles cannot enter, so parking is available at nearby public lots.
- What makes the Roman Bath architecturally unique?
- The bath features a horseshoe-shaped soaking tub modeled after ancient Roman thermae, a glass dome ceiling, walls decorated with tiles and terracotta by the renowned ceramicist Komori Shinobu, and a stunning peacock-motif stained glass partition by Beppu Shichirō. The Italian stained glass is irreplaceable, as it is no longer manufactured.
- Is the bath water a natural hot spring (onsen)?
- No, the Roman Bath and the Benten Cave Bath use heated tap water (wakashi-yu), not natural hot spring water. For onsen bathing on Enoshima, the nearby Enoshima Island Spa offers natural hot springs from 1,500 meters below the island.
Basic Information
| Name | Iwamotoro Roman Bath (岩本楼ローマ風呂) |
|---|---|
| Cultural Property Designation | Registered Tangible Cultural Property (Building) |
| Registration Date | November 20, 2001 |
| Construction Period | Circa 1930 (Early Showa era) |
| Structure | Single-story wooden building with glass roof; floor area approx. 43 m² |
| Location | 2-2-7 Enoshima, Fujisawa City, Kanagawa Prefecture |
| Owner | Iwamotoro Honkan Co., Ltd. |
| Facility | Iwamotoro Honkan (ryokan / traditional Japanese inn) |
| Access | Approx. 12 min walk from Katase-Enoshima Station (Odakyu Line); approx. 20 min walk from Enoshima Station (Enoden) or Shonan-Enoshima Station (Shonan Monorail) |
| Official Website | https://www.iwamotoro.co.jp/ |
References
- 岩本楼ローマ風呂 - 文化遺産オンライン
- https://bunka.nii.ac.jp/heritages/detail/178746
- 岩本楼ローマ風呂 - 国指定文化財等データベース（文化庁）
- https://online.bunka.go.jp/heritages/detail/178746
- 【公式】岩本楼の歴史 - 岩本楼
- https://www.iwamotoro.co.jp/history/
- 【公式】弁天洞窟風呂｜岩本楼ローマ風呂 - 岩本楼
- https://www.iwamotoro.co.jp/bath/
- 天然温泉に洞窟風呂！江の島で絶景お風呂に浸かろう - タイムズクラブ
- https://www.timesclub.jp/sp/tanomachi_ex/kanagawa/fujisawa/004.html
- 岩本楼 - 江の島・鎌倉ナビ
- https://enokama.jp/spot/10505/
Last verified: 2026.04.11