The first dark mouth on an abandoned railway
The Former Chuo Line Tamano Third Tunnel (旧中央線玉野第三隧道, Kyu-Chuosen Tamano Daisan Zuido) is a brick railway tunnel in Tamano-cho, Kasugai City, Aichi Prefecture, built in 1900 (Meiji 33) and listed as a Registered Tangible Cultural Property in 2016.
It runs 76 metres and measures 4.6 metres across, sized for a single track and no more. The bore is horseshoe shaped, a semicircular crown sitting on side walls that rise almost vertically. Get off the train at Jokoji Station on the JR Chuo Line, follow the narrow path below the platform upstream along the Shonai River for about 300 metres, and you reach the entrance gate. The Former Chuo Line Tamano Third Tunnel is the first opening beyond it, known locally as Tunnel No. 3.
Japan's Chuo Line between Nagoya and Tajimi was begun in November 1896 and opened on 25 July 1900. The stretch between Kozoji and Tajimi is barely ten kilometres long, yet it required fourteen tunnels to thread the hillsides above the river. Thirteen of them survive. Together they are known as the Aigi Tunnels.
Single track could not carry the traffic of postwar Japan. A new double tracked and electrified route was driven through longer bores on a different alignment, and in 1966 the old line was closed. Rails and sleepers were lifted, bamboo and scrub closed over the trackbed, and the tunnels were effectively forgotten until local residents went looking for them in 2005.
Listed for being hard to build again
Japan's registration system for cultural properties works through three criteria, and the Former Chuo Line Tamano Third Tunnel was listed under the third: structures that would not be easy to reproduce. Kasugai City's registration notice gives the reasoning plainly. The tunnel has a single track horseshoe section built to the standard pattern of the government railway, with a brick shell.
That wording matters. The tunnel was not protected because it is unusual. It was protected because it is ordinary and intact, an unaltered specimen of what a Meiji government railway tunnel was supposed to look like.
Registration followed a recommendation from the national Council for Cultural Affairs and took effect with the official gazette notice of 29 November 2016. Two neighbouring structures were listed at the same time, the Tamano Fourth Tunnel and the Kasaishihora Culvert, three items in all. They were the first cultural properties of any kind registered in Kasugai City, and the committee that cares for them notes that they were the first railway tunnels registered anywhere in the Tokai region. The owner is a non profit organisation, the Aigi Tunnel Group Preservation and Regeneration Committee.
What applies to the Former Chuo Line Tamano Third Tunnel is registration rather than designation, and Japanese law treats the two as separate instruments. Registration guards the exterior while leaving owners latitude inside, on the principle that a structure survives best when it is used. For a tunnel that people are invited to walk through twice a year, the fit is a good one.
Pilasters at the portal, recesses in the wall
The portal is what holds you first. The Agency for Cultural Affairs describes the face of the Former Chuo Line Tamano Third Tunnel as decorative, with applied pilasters and a base of dressed stone. Pilasters carry nothing. They are shallow columns laid against the wall face to catch light and shadow, and to give the mouth of a tunnel the manners of a building. Below them the cut stone runs like a plinth, and above the stone the red brick begins.
The western and eastern portals do not match. Kasugai City photographed both when the listing was announced, and the difference is easy to see once you know to look for it. The preservation committee makes a broader claim about the group as a whole, saying that no two portals among these tunnels share the same design, which suggests the engineers were given room to please themselves.
Inside, shallow niches interrupt the side walls at intervals. These are refuge recesses, the only place a track worker could stand clear of a train in a single track bore. Seventy six metres is short enough that daylight at the far end is visible from the near portal, and in that thin light you can make out the ballast still lying underfoot.
Run a hand across the lining and the mortar joints catch your fingertips. More than half a century passed with no maintenance at all, and the committee points out that almost no brick has fallen in that time.
A memorial stone at the tunnel mouth
A rough natural stone and a polished black panel stand together just short of the western portal. This is the memorial to the men who died building the Chuo Line, and it arrived at the Former Chuo Line Tamano Third Tunnel only in August 2025.
Local supporters raised it in June 1900, weeks before the line opened. Driving fourteen tunnels along an unstable hillside killed more than twenty men through rockfalls, landslides, injury and illness. In November 1897 the ground above the eastern portal of Tunnel No. 5 gave way and buried six labourers who were lining the bore with brick. The inscription heading the stone reads shi yu yoei, roughly "in death, honour without end".
The memorial first stood in the grounds of Taiheiji, a temple in Tamano-cho. It was moved in 2000, the centenary of the line, to the entrance of the Tokai Nature Trail, and moved again twenty five years later to the working face itself. Reading it before you step into the dark changes what the brickwork feels like.
When you can go, and what to bring
The trackbed containing the Former Chuo Line Tamano Third Tunnel is gated and locked for most of the year. Access is limited to the spring and autumn openings run by the preservation committee together with the Kasugai City Tourism and Convention Association, plus occasional events held on site. The 2026 autumn opening is announced for 28 November to 6 December, nine days.
At recent openings admission was 100 yen per person paid on the day, free for children of primary school age and younger, with no advance booking. Gates opened at 9:30, closed at 15:00, and last entry was 14:00. Rain cancels the day. The walking route covers Tunnels No. 3 to No. 6 and about 1.7 kilometres of trackbed, so 3.4 kilometres there and back, and roughly two hours at an unhurried pace. Prices and hours are set afresh for each opening, so check the committee's site before travelling.
Original ballast still covers much of the route, and it is loose. Wear shoes with a firm sole. The organisers ask visitors to bring a torch, which is as useful inside the bore as it is on the path. Pets are not admitted. No photography restriction has been published, and visitors' own pictures circulate freely on the committee's social media, but follow the signs and the stewards on the day.
Trains are the only sensible way in. Jokoji is served by local trains, a little over half an hour from Nagoya Station, and some rapid services also stop there during the opening periods. The station is unstaffed, so buy a return ticket or carry an IC card. Neither the site nor the station has any parking at all.
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Q&A
- Can I visit the Former Chuo Line Tamano Third Tunnel, and how much does it cost?
- Only during the spring and autumn special openings. The site is locked at all other times. At recent openings admission was 100 yen per person, free for children of primary school age and under, with no booking required. Gates ran 9:30 to 15:00 with last entry at 14:00. The 2026 autumn opening is announced for 28 November to 6 December.
- How do I get to the Former Chuo Line Tamano Third Tunnel from Nagoya?
- Take a local train on the JR Chuo Line to Jokoji Station, a little over half an hour. From the station, follow the small path below the platform upstream for roughly 300 metres, about five minutes on foot, to reach the reception point. Tunnel No. 3 lies immediately beyond it. There is no parking anywhere nearby.
- When was the Tamano Third Tunnel built, and when did trains stop running?
- It was built in 1900, the year the railway between Nagoya and Tajimi opened on 25 July. The single track line could not handle postwar traffic, so a new double tracked route was built on a different alignment and the old section between Kozoji and Tajimi closed in 1966.
- How long is the Tamano Third Tunnel and what is it built from?
- Brick throughout, 76 metres long and 4.6 metres wide. The bore has the horseshoe section standard for single track government railway tunnels. Refuge recesses are set into the side walls, and the portal carries applied pilasters above a base of dressed stone.
- What is the stone monument in front of the Tamano Third Tunnel?
- A memorial to the more than twenty workers who died building the railway between Kozoji and Tajimi. Local residents erected it in June 1900. It stood at Taiheiji temple, then at the Tokai Nature Trail entrance from 2000, and was moved to the tunnel mouth in August 2025.
Basic Information
| Name | Former Chuo Line Tamano Third Tunnel (旧中央線玉野第三隧道) |
|---|---|
| Location | 1664-1 Higashitani, Tamano-cho, Kasugai City, Aichi Prefecture, and other locations |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2016 (Heisei 28) |
| Quantity | 1 unit |
| Dimensions | Length 76 metres, width 4.6 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 Tamano Third Tunnel
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00011315
- 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: modern industrial heritage and registered cultural properties
- https://aigi-tunnel.org/bunkazai-kinsan.html
- Aigi Tunnel Group Preservation and Regeneration Committee: relocation of the Chuo Line construction memorial to Tunnel No. 3
- https://aigi-tunnel.org/News/2025/20250805_Junshokusha-Ireihi.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