Hirayama Bridge: A Taisho-Era Steel Truss Bridge with Wartime Scars
Spanning the clear waters of the Nakatsu River in Aikawa Town, Kanagawa Prefecture, Hirayama Bridge (平山橋) stands as a remarkable testament to early 20th-century Japanese civil engineering. This three-span curved-chord Pratt truss steel bridge, stretching 112.71 meters in length with a width of 4.5 meters, has served the local community for over a century. Registered as a National Tangible Cultural Property in 2004, Hirayama Bridge is not only a significant piece of industrial heritage but also a poignant war memorial bearing bullet scars from a World War II strafing attack.
Historical Background
The history of Hirayama Bridge begins in 1913 (Taisho 2), when the left bank (north side) span was first constructed as a steel truss bridge. The remaining two spans were initially wooden bridges. It was not until 1926 (Taisho 15) that all three spans were rebuilt in steel, giving the bridge its current appearance. A nameplate on the right bank spans identifies Ando Iron Works of Tsukishima, Tokyo, as the manufacturer — a company with a bridge-building record spanning from 1918 to 1975. The manufacturer of the original 1913 left bank span remains unknown.
On July 10, 1945, just weeks before the end of World War II, Hirayama Bridge was strafed by American fighter aircraft. The attack left numerous bullet holes in the bridge's structural members and railings, with some rounds penetrating steel plates approximately 8 millimeters thick. Tragically, people on and around the bridge were killed or injured during the attack. For local residents, Hirayama Bridge serves as an important war memorial, a tangible reminder of the devastating impact of the conflict on everyday civilian life.
Why Hirayama Bridge Was Designated a Cultural Property
Hirayama Bridge was registered as a National Tangible Cultural Property (Registered Tangible Cultural Property — Structures) on November 8, 2004. Riveted steel bridges from the Taisho era (1912–1926) have become increasingly rare in Japan, making Hirayama Bridge a valuable surviving example of early modern bridge engineering. The curved-chord Pratt truss design, with stone-clad piers featuring neatly laid ashlar masonry, represents a significant type of bridge construction from this period. Each of the three spans has a clear length of approximately 37 meters.
In addition to its national registration, Hirayama Bridge has been recognized as one of the "100 Bridges of Kanagawa" and has been selected by the Japan Society of Civil Engineers as a "Heritage of Modern Civil Engineering in Japan," further underscoring its importance in the nation's engineering history.
Highlights and Points of Interest
Taisho-Era Riveted Steel Construction
One of the most striking features of Hirayama Bridge is its riveted steel construction, a technique widely used in the early 20th century before welding became standard. The exposed rivets and robust truss framework offer visitors an up-close look at historic engineering methods. Walking across the bridge, you can appreciate the craftsmanship of an era when each rivet was individually heated and hammered into place.
Wartime Bullet Holes
Scattered across the bridge's railings and structural members are bullet holes from the July 1945 strafing attack. Some of these holes pierce through steel plates, giving a powerful sense of the violence inflicted. An information board near the bridge provides historical context about the attack and its impact on the community.
Evening Illumination
At night, Hirayama Bridge is illuminated, creating a dreamlike scene over the Nakatsu River. The combination of the lit-up steel framework reflected in the flowing water, accompanied by the gentle sound of the river, makes for an atmospheric experience quite different from a daytime visit.
Pedestrian-Only Walkway
Today, Hirayama Bridge serves exclusively as a pedestrian and bicycle path, allowing visitors to stroll across at a leisurely pace and examine its historical features without concern for vehicular traffic. The bridge connects the Tashiro Sports Park area to the Hirayama district on the opposite bank.
Surrounding Area and Access
Hirayama Bridge is located along Kanagawa Prefectural Route 54, near Tashiro Sports Park in Aikawa Town. The area along the Nakatsu River is popular for riverside recreation, with several scenic spots for walking and picnicking. Aikawa Town itself, situated in the northern part of Kanagawa Prefecture where the Tanzawa Mountains begin to rise, offers a range of outdoor activities.
Nearby attractions include the Aikawa Town Local History Museum, the Sanzō Battlefield Site (a famous Sengoku-period battle site), and the Miyagase Dam area. The charming Higata Bridge, another notable bridge in the area, is also worth visiting.
Access is via Kanagawa Chuo Kotsu bus from Hon-Atsugi Station on the Odakyu Odawara Line. Take a bus bound for Hanso-bo or Tashiro and alight at Hanso-bo-mae or Tashiro bus stop (approximately 40 minutes). The bridge is a short walk from either stop. Note that there is no dedicated parking at the bridge itself.
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Q＆A
- Can I drive across Hirayama Bridge?
- No. Hirayama Bridge is currently designated as a pedestrian and bicycle-only path. Vehicles use the nearby Hirayama Ohashi Bridge instead.
- Where can I see the wartime bullet holes?
- The bullet holes from the 1945 strafing attack are visible on the bridge's railings and structural steel members. Look carefully at the steel plates as you walk across — some holes penetrate through the metal entirely. An information board near the bridge provides details.
- Is there an admission fee to visit Hirayama Bridge?
- No. Hirayama Bridge is a public pedestrian walkway and can be visited free of charge at any time.
- Is the bridge illuminated at night?
- Yes. Hirayama Bridge is lit up in the evening, creating a beautiful and atmospheric scene over the Nakatsu River.
- How do I get to Hirayama Bridge by public transport?
- From Hon-Atsugi Station on the Odakyu Line, take a Kanagawa Chuo Kotsu bus toward Hanso-bo or Tashiro. Get off at Hanso-bo-mae or Tashiro bus stop (about 40 minutes), then walk approximately 3 minutes to the bridge.
Basic Information
| Name | Hirayama Bridge (平山橋) |
|---|---|
| Location | Tashiro, Aikawa Town, Aiko District, Kanagawa Prefecture (along Prefectural Route 54) |
| Structure | Three-span curved-chord Pratt truss steel bridge |
| Length | 112.71 meters |
| Width | 4.5 meters |
| Span Length | Approximately 37 meters per span |
| Construction | 1913 (left bank span); 1926 (all three spans completed in steel) |
| Manufacturer | Ando Iron Works, Tsukishima, Tokyo (right bank spans); left bank span manufacturer unknown |
| Cultural Property Registration | Registered Tangible Cultural Property (Structures), registered November 8, 2004 |
| Owner | Aikawa Town |
| Current Use | Pedestrian and bicycle path |
| Access | Bus from Hon-Atsugi Station (Odakyu Line) to Hanso-bo-mae or Tashiro stop, then 3-minute walk |
References
- 平山橋 - 愛川町観光協会
- https://www.town.aikawa.kanagawa.jp/aikawa_kankoukyoukai/Sightseeing/1497668598408.html
- 平山橋 - 文化遺産オンライン
- https://bunka.nii.ac.jp/heritages/detail/189070
- 平山橋 (神奈川県) - Wikipedia
- https://ja.wikipedia.org/wiki/%E5%B9%B3%E5%B1%B1%E6%A9%8B_(%E7%A5%9E%E5%A5%88%E5%B7%9D%E7%9C%8C)
- 戦争の傷跡も残る、文化財。平山橋を渡ってみませんか？ - ポケットに愛川
- https://pocketniaikawa.com/a_016/
Last verified: 2026.04.10