A passage for water, hidden under the embankment
The Former Chuo Line Kasaishihora Culvert (旧中央線笠石洞暗渠, Kyu-Chuosen Kasaishihora Ankyo) is a brick culvert in Kitsuki-cho, Kasugai City, Aichi Prefecture, built in 1900 (Meiji 33) and listed as a Registered Tangible Cultural Property in 2016.
Three structures on this abandoned stretch of the old Chuo Line carry cultural property status, and this is the only one that is not a tunnel. Its mouth opens beneath the embankment about 300 metres towards Tajimi from the Tamano Fourth Tunnel, just short of the Kasugai portal of Tunnel No. 5.
The logic behind it is worth spelling out. When a railway is carried along a hillside, the small valleys in its path are filled with earth. Filling them leaves the streams that drained those valleys with nowhere to go, and water trapped in an embankment will eventually take the formation with it. Every embankment therefore needs a way to pass water through. The Former Chuo Line Kasaishihora Culvert is that provision, built in brick and still standing.
One note on the name. The Agency for Cultural Affairs gives the reading as Kasaishihora, while the owner writes it Kasaishibora. The two are not reconciled in the published sources, and this article follows the Agency as the primary record.
Nine metres down, eleven metres across
The section is rectangular rather than arched, and only 1.2 metres wide, which is about enough for one person to move through in a crouch.
Two elements make up the structure. A vertical shaft roughly nine metres deep gathers water on the valley side and drops it, and a horizontal bore of about eleven metres carries it out towards the Shonai River. The figure of eleven metres that appears in the Agency's structural description refers to that horizontal run. Drop the water, then move it sideways: the arrangement is plain, and it works without any moving part.
Kasugai City states the reason for registration in a single line, describing a brick culvert built to pass valley water when the track was carried on an embankment, incorporating a vertical shaft. The criterion applied was the third of the three, covering structures that would not be easy to reproduce.
The record carries one more detail. The Agency dates the structure to 1900 with repairs in 1957 (Showa 32). A repair in that year means the culvert was still being inspected and maintained as working equipment, nine years before the line closed in 1966. Nothing about the Former Chuo Line Kasaishihora Culvert was built to be admired, and yet somebody kept coming back to it as long as trains ran overhead.
Four flights of stairs below the trackbed
You will not see this structure while walking the old railway, because it sits well below the level trains once used. Reaching it means descending four flights of steps from beside the Kasugai portal of Tunnel No. 5 towards the floor of the valley.
Those stairs are the committee's own work. For years the lower two flights were timber, and with tens of thousands of people walking the site during a single autumn opening they wore out and were patched again and again. Between February and March 2026 the lower two were replaced in steel, so all four flights are now steel built. According to the committee's report, from the bottom of the last flight it is about 50 metres forward to the culvert entrance.
Running alongside the foot of that descent is the Tamano Kodo, the old Tamano road. Merchants of Tajimi funded it as a toll road and it opened in 1895 (Meiji 28), a flat route along the river for people, packhorses and carts. Railway construction cut it in several places from 1896, and once the line opened in 1900 the road fell out of use. Its working life lasted little more than a year.
So the valley floor holds two things within a few dozen metres of each other: a road the railway destroyed, and the Former Chuo Line Kasaishihora Culvert, which the railway built to manage the water of the same valley. Neither is visible from the trackbed above.
When you can go, and what the descent asks of you
The land holding the Former Chuo Line Kasaishihora Culvert is gated and locked outside the two annual openings and occasional events held on the grounds. The openings are run by the owner, the Aigi Tunnel Group Preservation and Regeneration Committee, together with the Kasugai City Tourism and Convention Association. The 2026 autumn opening is announced for 28 November to 6 December, nine days in all.
At recent openings admission was 100 yen per person paid on the day, free for children of primary school age and under, with no advance booking. Gates opened at 9:30 and closed at 15:00, last entry 14:00, and rain cancelled the day. The walking route covers Tunnels No. 3 to No. 6 and about 1.7 kilometres of trackbed, 3.4 kilometres there and back, roughly two hours. Allow extra time if you intend to go down to the culvert. Fees and hours are set again for each opening, so check the committee's site first.
Loose ballast from the working railway still covers the formation, so wear shoes with a firm sole, and dress so that you can use a handrail on the way down. The organisers ask visitors to carry a torch, which matters more here than anywhere else on the route. Pets are not admitted. No photography restriction has been published and visitors' pictures circulate on the committee's social media, but follow the signs and the stewards on the day.
Come by train. Jokoji Station on the JR Chuo Line is a little over half an hour from Nagoya on a local service, with some rapid services calling during opening periods, and the reception point is roughly 300 metres upstream of the platform along a small path, about five minutes on foot. The station is unstaffed, so carry a return ticket or an IC card. There is no parking at the site or near the station.
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Q&A
- What is the Former Chuo Line Kasaishihora Culvert for?
- It carries stream water through a railway embankment. When the valley was filled to take the track, the water needed a way out, so engineers built a vertical shaft about nine metres deep to catch it and a horizontal bore of about eleven metres to discharge it towards the Shonai River. The section is rectangular, 1.2 metres wide, and built of brick.
- How do I reach the Former Chuo Line Kasaishihora Culvert?
- It lies in Kitsuki-cho, Kasugai City, under the embankment about 300 metres towards Tajimi from Tunnel No. 4. From beside the Kasugai portal of Tunnel No. 5 you descend four flights of steel stairs, then walk about 50 metres to the entrance. The trackbed itself is only accessible during the spring and autumn openings.
- When was the Kasaishihora Culvert built and when was it registered?
- It was built in 1900, the year the railway between Nagoya and Tajimi opened, and repaired in 1957. It was registered as a cultural property by gazette notice on 29 November 2016, at the same time as the Tamano Third Tunnel and the Tamano Fourth Tunnel.
- Is the Kasaishihora Culvert the reading Kasaishihora or Kasaishibora?
- Sources differ. The Agency for Cultural Affairs database gives Kasaishihora, while the owning committee writes Kasaishibora on its own site. This article follows the Agency as the primary source, but both forms are in circulation.
- What else is near the Kasaishihora Culvert?
- The Tamano Kodo runs along the valley floor beside it, the remains of a toll road opened in 1895 that was cut apart by railway construction from 1896 and abandoned once the line opened in 1900. Back up on the formation, the Tamano Fourth Tunnel stands about 300 metres towards Kasugai.
Basic Information
| Name | Former Chuo Line Kasaishihora Culvert (旧中央線笠石洞暗渠) |
|---|---|
| Location | 39-2, Kakureyama, Kitsukicho, Kasugai City, Aichi Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2016 (Heisei 28) |
| Quantity | 1 unit |
| Dimensions | Length 11 metres, width 1.2 metres (vertical shaft about 9 metres) |
| Owner | Aigi Tunnel Group Preservation and Regeneration Committee (NPO) |
| Public Access | Open only during the spring and autumn special openings; locked and closed at other times |
References
- Agency for Cultural Affairs, National Cultural Properties Database: Former Chuo Line Kasaishihora Culvert
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00011317
- Kasugai City: Notice of registration as Registered Tangible Cultural Properties (structures)
- https://www.city.kasugai.lg.jp/bunka/bunkazai/shinai/1004355.html
- Aichi Prefecture: Announcement of registered tangible cultural properties (structures)
- https://www.pref.aichi.jp/soshiki/bunkazai/tourokubunnkazaikennzoubutu.html
- Aigi Tunnel Group Preservation and Regeneration Committee: replacement of the stairs down to the culvert
- https://aigi-tunnel.org/News/2026/202603marche.html
- Aigi Tunnel Group Preservation and Regeneration Committee: about the Aigi Tunnels and the Tamano Kodo
- https://aigi-tunnel.org/about_tunnel.html
- Aigi Tunnel Group Preservation and Regeneration Committee: report on the 36th spring opening, with visiting details
- https://aigi-tunnel.org/News/2026/2026Haru-houkoku.html
Last verified: 2026.08.31