A Shell Roof Above Sasebo Harbour
The Yumiharidake Observatory (弓張岳展望所) is a lookout shelter of 1965 in Yatakecho, Sasebo City, Nagasaki Prefecture, and was registered as a Registered Tangible Cultural Property (structure) on August 6, 2025 (Agency for Cultural Affairs).
The Agency records a reinforced concrete shelter roofed in copper, 69 square metres, on a stone base, renovated in 2010; registration number 42-0146.
A Lookout for a National Park's Tenth Year
The Yumiharidake Observatory was built on a hill above Sasebo Bay to mark the tenth anniversary of Saikai National Park (Agency for Cultural Affairs). Sasebo City says it put up the shelter in 1965 as part of Yumihari Park, with a sweeping view from near the summit over Sasebo Harbour and the Kujūku Islands.
The mayor has explained that the city hoped to shake off its image as a naval port and grow peacefully by protecting and using its natural scenery. Around 100,000 people a year now visit the lookout (Sasebo City).
Why It Was Registered
The Agency notes that a thin, upswept roof resting on just 2 points in front and 1 behind was achieved with a reinforced concrete hyperbolic paraboloid shell. It calls the work a small piece by the structural engineer Tsuboi Yoshikatsu whose sharp form stands out against the landscape, and registered it as a model of design.
What to Look For
The rear support bears a relief of a bow and waves by the sculptor Hongō Shin (Agency for Cultural Affairs). Sasebo City likens the shelter to a bird kicking off from its stone base, and gives the sculpture the title Shooting the Sun.
Find the 3 points that carry the roof, then step beneath the upturned shell and take in the view of the harbour and islands (Agency for Cultural Affairs; Sasebo City).
Visiting
The observatory is an open-air structure within Yumihari Park (Sasebo City). No official information on opening hours or transport was found.
Q&A
- When was the Yumiharidake Observatory built?
- Sasebo City built it in 1965.
- Who designed the Yumiharidake Observatory roof?
- The structural engineer Tsuboi Yoshikatsu.
- What can you see from the Yumiharidake Observatory?
- Sasebo Harbour and the Kujuku Islands.
- Who made the relief on the Yumiharidake Observatory?
- The sculptor Hongo Shin.
- When was the Yumiharidake Observatory registered?
- On August 6, 2025 (Agency for Cultural Affairs).
Basic Information
| Name | Yumiharidake Observatory (弓張岳展望所) |
|---|---|
| Location | Yatakecho, Sasebo City, Nagasaki Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2025/08/06 (Reiwa 7) |
| Quantity | 1 building |
| Dimensions | Reinforced concrete, copper roof, 69 m², with stone base |
| Owner | Sasebo City |
| Public Access | Open-air structure (no official hours published) |
References
- Yumiharidake Observatory (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/101/00015524
- Mayor's comment on the registration of the Yumiharidake Observatory (Sasebo City, Japanese)
- https://www.city.sasebo.lg.jp/mayor/message/soumu/kouhou/070321umiharitenbousyo.html
- Yumiharidake Observatory (Cultural Heritage Online, Japanese)
- https://online.bunka.go.jp/heritages/detail/623549
Last verified: 2026.10.15